Objective:To assess the effects of melatonin and/or cysteamineonin vitro maturation, culturing and post-warming of buffalo embryos.Methods: Buffalo oocytes were classified into control, cysteamine (50 μM), melatonin ...Objective:To assess the effects of melatonin and/or cysteamineonin vitro maturation, culturing and post-warming of buffalo embryos.Methods: Buffalo oocytes were classified into control, cysteamine (50 μM), melatonin (10 ng/mL) and cysteamine (50 μM) + melatonin (10 ng/mL) treatment groups. In experiment 1, previous treatments were added duringin vitromaturation and culturing of buffalo oocytes.Results:Cleavage and blastocyst rates were significantly (P<0.05) increased in melatonin treated group (70.5±0.9 and 12.8±1.0, respectively). However this effect was potentiated when combined with cysteamine (74.0±1.7 and 14.8±1.7, respectively). In experiment 2, the treatements were added in maturtaion, culturing as well as post-warming culture media. Embryos at 7 d were vitrified.Viability assessement directly after warming showed significant increase (P<0.05) in cysteamine, melatonin and their combination groups (76.8±2.8, 80.0±2.1 and 83.3±1.7, respectively) than control (65.8±2.4);but the viability after 24 h post-warming was the best in cysteamine + melatonin combination group (61.4±2.1).Conculsions: Enriching maturation, culturing and post-warming media of buffalo oocytes and embryos with melatonin and/or cysteamine have significantly beneficial effects on oocyte developmental competence as well as embryos vitrification procedure outcomes which in turn resulting in enhancement of commercial buffalo embryo production.展开更多
Objective:To compare the outcomes of vitrification using cryoloop with slow-freezing meth-od for human blastocyst cryopreservation.Methods:In IVF-ET cycles,supernumerary embryos were cultured to Day 5 or Day 6,blas-to...Objective:To compare the outcomes of vitrification using cryoloop with slow-freezing meth-od for human blastocyst cryopreservation.Methods:In IVF-ET cycles,supernumerary embryos were cultured to Day 5 or Day 6,blas-tocysts were cryopreserved by vitrification using cryoloops or slow-freezing method,then blasto-cyst survival rate and pregnant rate were compared.Results:115 vitrified blastocysts from 39 cycles were warmed,104(90.4%)blastocysts sur-vived.After the transfer of 74 blastocysts in 38 cycles,28(73.7%)women got clinically preg-nant,2(7.1%)of them suffered from miscarriage,2 healthy babies were born in 2 deliveries,and the other 24 pregnancies are ongoing.As to slow-freezing method,87 blastocysts from 21 cy-cles were thawed,37(42.5%)of them survived,28 blastoeysts were transferred in 15 cycles,6(40%)women got clinically pregnant,1 of them miscarried,3 healthy babies were born in 2 de-liveries,and the other 3 pregnancies are ongoing.Conclusion:The survival rate and pregnant rate of vitrification using cryoloop are superior totraditional slow-freezing method,and the transfer cancel rate is lower than that of slow-freezingmethod.The miscarriage rate is similar in two methods.展开更多
Bovine oocytes cultured in vitro for 6 hours or 22 hours were cryopreserved in different vitrification solutions (EFS40, EFS50, EDFS30 or EDFS40) by the two-step method with OPS (open pulled straw).The best results we...Bovine oocytes cultured in vitro for 6 hours or 22 hours were cryopreserved in different vitrification solutions (EFS40, EFS50, EDFS30 or EDFS40) by the two-step method with OPS (open pulled straw).The best results were achieved by using EDFS30 to cryopreserve the oocytes either for in vitro fertilization or for chemical activation. The blastocyst rates were 12% and 17% in 6 hour and 22 hour cultures respectively following in vitro fertilization. If frozen-thawed oocytes were continued in culture up to 24 hours, and were activated by chemicals, the blastocyst rates were 22% and 24% in 6-hour and 22-hour groups respectively.There were no statistical differences between frozen and fresh oocytes (P ＞ 0.05).展开更多
Background: In order to assess the chromosomal status in embryos obtained from vitrified and fresh donated oocytes, preimplantational genetic diagnostic (PGD) was performed after biopsy of one blastomere at day 3. MET...Background: In order to assess the chromosomal status in embryos obtained from vitrified and fresh donated oocytes, preimplantational genetic diagnostic (PGD) was performed after biopsy of one blastomere at day 3. METHODS: A total of 249 oocytes were obtained from 23 oocyte donors, 80 oocytes were used in the vitrified group and 151 oocytes were used in the fresh group. Nine chromosomes (13, 15, 16, 17, 18, 21, 22, X and Y) were investigated by fluorescence in situ hybridization (FISH) analysis in 56 and 121 embryos from vitrified and fresh group respectively. Fertilization, cleavage rate, embryo quality and chromosomal abnormality rate were compared between groups evaluated. Results: Vitrified oocytes showed a survival rate of 97.5%. There was no significant difference in the fertilization rate (82.7% and 91.4%), Day 2 cleavage rate (90.3% and 87.7%) or blastocyst formation rate (31.1% and 44.6%) for the vitrified and fresh groups respectively. Chromosomal abnormality rate (66.1% versus 71.9%), percentage of abnormal blastocysts (61.1% versus 64.8%) and percentage of abnormalities for each analyzed chromosome were similar for the vitrified group compared with the control group. Conclusions: The rates of chromosomal abnormalities in embryos from vitrified oocytes are similar to those published previously;and comparable to those observed in embryos from fresh oocytes. These results confirm that the developmental competence and chromosomal status of embryos obtained from vitrified oocytes is not affected by the vitrification procedure, and they preserve the potential to be fertilized and to develop in to blastocyst stage similar to embryos from fresh oocytes.展开更多
Background:Currently,there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes.To date,vitrification(VIT)is...Background:Currently,there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes.To date,vitrification(VIT)is the most efficient method for pig embryo cryopreservation.Despite a high number of embryos survives in vitro after vitrification/warming procedures,the in vivo embryo survival rates after embryo transfer are variable among laboratories.So far,most studies have focused on cryoprotective agents and devices,while the VIT effects on porcine embryonic gene expression remained unclear.The few studies performed were based on vitrified/warmed embryos that were cultured in vitro(IVC)to allow them to re–expand.Thus,the specific alterations of VIT,IVC,and the cumulative effect of both remained unknown.To unveil the VIT-specific embryonic alterations,gene expression in VIT versus(vs.)IVC embryos was analyzed.Additionally,changes derived from both VIT and IVC vs.control embryos(CO)were analyzed to confirm the VIT embryonic alterations.Three groups of in vivo embryos at the blastocyst stage were analyzed by RNA–sequencing:(1)VIT embryos(vitrified/warmed and cultured in vitro),(2)IVC embryos and(3)CO embryos.Results:RNA–sequencing revealed three clearly different mRNA profiles for VIT,IVC and CO embryos.Comparative analysis of mRNA profiles between VIT and IVC identified 321,differentially expressed genes(DEG)(FDR<0.006).In VIT vs.CO and IVC vs.CO,1901 and 1519 DEG were found,respectively,with an overlap of 1045 genes.VIT-specific functional alterations were associated to response to osmotic stress,response to hormones,and developmental growth.While alterations in response to hypoxia and mitophagy were related to the sum of VIT and IVC effects.Conclusions:Our findings revealed new insights into the VIT procedure-specific alterations of embryonic gene expression by first comparing differences in VIT vs.IVC embryos and second by an integrative transcriptome analysis including in vivo control embryos.The identified VIT alterations might reflect the transcriptional signature of the embryo cryodamage but also the embryo healing process overcoming the VIT impacts.Selected validated genes were pointed as potential biomarkers that may help to improve vitrification.展开更多
The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vit...The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.展开更多
Objective:To assess effect of buffalo bull breed on the development and cryotolerence of the in vitro produced embryos.Methods: Three types of frozen semen were adopted;Egyptian, Italian and cross-bred (Egyptian-Itali...Objective:To assess effect of buffalo bull breed on the development and cryotolerence of the in vitro produced embryos.Methods: Three types of frozen semen were adopted;Egyptian, Italian and cross-bred (Egyptian-Italian) breeds were used for in-vitro fertilization and vitrification of their embryos. Oocytes were collected from buffalo ovaries and maturedin vitrofor 24 h, then they were fertilized using the three semen breeds. The produced embryos of morula and blastocysts were vitrified using ethylene glycol and dimethyl sulfoxide then evaluated for their viability after warming.Results: The cleavage and blastocysts rates significantly declined in oocytes fertilized by Egyptian (P<0.01) than in Italian (P<0.05) and crossbred (P<0.05) frozen semen. After embryo vitrification, there were no significant differences among the three breeds in the percentages of morphologically viable embryos evaluated directly after warming and at 24 h post-culture. Conclusions:Thein vitro fertilization response to frozen-thawed semen varies between breeds;however, the resistance of produced embryos to the damage effect of vitrification does not vary.展开更多
Objective: To assess the developing potentiality of mouse morula produced in vitro or in the after vitrification and to evaluate the effect of one-step and two-step vitrification methods. Method: Mouse morula produced...Objective: To assess the developing potentiality of mouse morula produced in vitro or in the after vitrification and to evaluate the effect of one-step and two-step vitrification methods. Method: Mouse morula produced in for and in the were vitrified in the solution containing ethylene glycol, Ficoll and sucrose (EFS solution) with one-step and two-step methods. The developing potential and status of the pellucid zona in vitified mouse morula were assessed. Results: The percentages of morula developed into blastocyst stage were 81. 8% and 82.4%, 97. 3% and 98.4%, respectively, after one-step and two-step exposure of in vitro morula or in vivo morula to EFS solution alone, which did not show significant difference compared to their controls (P > 0. 05). The percentage of in vitro morula developed into blastocyst vitrified by onestep method was significantly lower than that by two-step method and coned (P < 0.05, 70.6% vs 81 .3%; 70.6% vs 83 .6%, respectively). However, there was no significant difference between blastocyst rates of in vivo morula vitrified by one-step and two-step methods (P>0.05, 93. 1% us 95.7%). No rupture of pellucid zona was observed in all thawed morula after one-step and two-step vitrification, irrespective of in vitro morula or in vivo morula. Conclusion: Morula produced in vitro and in vivo after vitrification may maintain high survival rate and developing potential. Two-step vitrification method with EFS solution is suitable for in vitro morula, which can improve the developing potential of in vitro morula. Onestep and two-step vitrification method have no detrimennd effect on the developing potential of in vivo morula.展开更多
Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentr...Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.展开更多
Vitrification of immature oocytes at the germinal vesicle (GV) stage is important to preserve female gametes. The standard formula for vitrification solutions has long been a debate. Herein, we investigated the effect...Vitrification of immature oocytes at the germinal vesicle (GV) stage is important to preserve female gametes. The standard formula for vitrification solutions has long been a debate. Herein, we investigated the effect of the presence or absence of trehalose in vitrification solution on viability, in vitro maturation (IVM) rates, and development of vitrified/warmed immature dromedary camel oocytes. Cumulus oocyte complexes (COCs) obtained at slaughter from the ovaries of mature she-camels were randomly allocated into three groups;namely, control group, oocytes were directly subjected to IVM without vitrification, vitrification solution 1 (VS1) group, oocytes were vitrified in a solution composed of 25% ethylene glycol (EG) plus 25% dimethyl sulfoxide (DMSO) + 0.5 M trehalose;and vitrification solution 2 (VS2) group, oocytes were vitrified in a solution composed of 25% EG plus 25% DMSO. Vitrification of COCs was conducted by open pulled straws (OPS) method. Following vitrification and warming, morphologically viable oocytes were matured in vitro for 36 h. COCs were then fertilized and cultured in vitro for 7 days. The percentage of viable oocytes was significantly higher (P 0.05) in VS2 than VS1 group (80.0% vs. 63.3%, respectively). Nuclear maturation, cleavage (48 h post-insemination;pi), and blastocyst rates (7 days pi) were significantly higher (P < 0.05) in VS2 than in VS1 groups. No significant differences were observed in oocyte maturation and development rates between VS2 and control groups. In conclusion, vitrification of immature dromedary camel oocytes in trehalose-free solution (VS2) was more advantageous than that in trehalose supplemented media since it did not reduce viability and development.展开更多
Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) ...Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.展开更多
Is there a really need to validate oocyte vitrification technique in an ART laboratory before establishing it in daily practice? Validation of micromanipulationbased technique, in this case oocyte vitrification, is es...Is there a really need to validate oocyte vitrification technique in an ART laboratory before establishing it in daily practice? Validation of micromanipulationbased technique, in this case oocyte vitrification, is essential prior to enlarging its use to routine practice. Oocyte vitrification is a new worldwide used technique and legal recently inFrance. This micromanipulation needs to be performed by a skilled and experienced embryologist and requires an internal assessment in each ART unit before any wide use. We designed a prospective study, from September 2011 to July 2012, using sibling oocytes from women who recovered more than 12 Metaphase II oocytes. A part of freshly recovered oocytes underwent immediate ICSI while the remaining oocytes were vitrified. 87 couples undergoing ICSI were selected based on number of mature oocytes available on the recovery day after denudation. A part of fresh MII oocytes were microinjected and the others were vitrified using an open system (Cryotop?). The major criterion of interest was the number of embryo transferred/ number of Metaphase II ratio for after ICSI on fresh oocytes (42/211) versus vitrified/warmed oocytes (51/204) (p > 0.05). Secondary studied criteria were survival rate (80.5% ± 26.3%), fertilization rate (68.9 ± 33.5) and finally, cumulative pregnancy rate obtained in this study is 40.2%. One of the benefits of such practice is the limitation of embryo freezing. However, the study design delays oocytes warming cycles, due to pregnancies triggered by the transfer of fresh derived oocyte embryos and to the priority to transfer all the frozen embryos before starting oocytes warming. Moreover, no data is available about children’ health. Oocyte vitrification represents not only a change in our daily practice to improve cumulative pregnancy rate but also a promising tool to develop egg banking and donation. Clinical Trials Registration number: 209 R02.展开更多
Oocyte cryopreservation is widely used for clinical and social reasons.Previous studies have demonstrated that conventional slow-freezing cryopreservation procedures,but not storage time,can alter the gene expression ...Oocyte cryopreservation is widely used for clinical and social reasons.Previous studies have demonstrated that conventional slow-freezing cryopreservation procedures,but not storage time,can alter the gene expression profiles of frozen oocytes.Whether vitrification procedures and the related frozen storage durations have any effects on the transcriptomes of human metaphase Ⅱ oocytes remain unknown.Four women(30–32 years old)who had undergone IVF treatment were recruited for this study.RNA-Seq profiles of 3 fresh oocytes and 13 surviving vitrified-thawed oocytes(3,3,4,and 3 oocytes were cryostored for 1,2,3,and 12 months)were analyzed at a single-cell resolution.A total of 1987 genes were differentially expressed in the 13 vitrifiedthawed oocytes.However,no differentially expressed genes were found between any two groups among the 1-,2-,3-,and 12-month storage groups.Further analysis revealed that the aberrant genes in the vitrified oocytes were closely related to oogenesis and development.Our findings indicated that the effects of vitrification on the transcriptomes of mature human oocytes are induced by the procedure itself,suggesting that long-term cryostorage of human oocytes is safe.展开更多
CRYOPRESERVATION by vitrification is a new ultralow-temperature-storage technique developed in the 1980s. Operationally, procedures for vitrification of biological specimens consist of the following basic steps: treat...CRYOPRESERVATION by vitrification is a new ultralow-temperature-storage technique developed in the 1980s. Operationally, procedures for vitrification of biological specimens consist of the following basic steps: treatment of the samples in a highly concentrated vitrification solution and then plunging the specimens into liquid nitrogen. The word 'vitrification' is sometimes used to describe the high moisture of the in vitro cultures or regenerants. However, in this note, this word means a biophysical process in which the cells and the solution are transformed into a homogeneous and amorphous state. The water in cells does not change into ice, but in展开更多
Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice.However,it has been shown to have a negative impact on sperm function and structure.Vitrification as a suc...Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice.However,it has been shown to have a negative impact on sperm function and structure.Vitrification as a successful alternative method has been proved to have better protective effects on human embryos,but vitrification of spermatozoa is still subject to low recovery rates.In this study,a modified vitrification method for native spermatozoa was developed.A total of 28 semen samples were included;each sample was divided into three equal parts and assigned to fresh,slow freezing,and vitrification groups.Sperm vitality,motility,morphology,DNA integrity,and acrosome reaction were assessed for each of the groups.The results showed that vitrification achieves better results for several sperm protection parameters than slow freezing;vitrification achieves a higher recovery rate(P<0.05),motility(P<0.05),morphology(P<0.05),and curve line velocity(P<0.05)than slow freezing.Furthermore,DNA fragmentation was decreased(P<0.05)and better acrosome protection(P<0.05)was exhibited in the spermatozoa after vitrification.Principal component analysis of all sperm parameters revealed that the vitrification cluster was closer to the fresh cluster,indicating that spermatozoa are better preserved through vitrification.In conclusion,while both slow freezing and vitrification have negative effects on sperm function and structure,the vitrification protocol described here had a relatively better recovery rate(65.8%)and showed improved preservation of several sperm quality parameters compared with slow freezing.展开更多
Objective: To evaluate the effect of morphologic factors on survival rate (SR), pregnancy rate (PR), and implantation rate (IR) of human embryo vitrification following frozen embryo transfer (FET) on day 3 post-ovulat...Objective: To evaluate the effect of morphologic factors on survival rate (SR), pregnancy rate (PR), and implantation rate (IR) of human embryo vitrification following frozen embryo transfer (FET) on day 3 post-ovulation.Methods: Women undergoing FET (n = 921) with embryos cryopreserved by vitrification between 2012 and 2013 were enrolled in this retrospective cohort study.Results: Embryos with >9 blastomeres yielded the highest SR of 100%. Lower SR was observed in embryos with 5 to 6 (57.5%) and 4 blastomeres (41.4%). In terms of blastomere symmetry, the SR of embryos with equally sized blastomeres was significantly higher than that of embryos with unequally sized cells (82.5%vs. 64.6%,P < 0.05). As fragmentation increased, SR decreased from 92.1% to 20.6% (P < 0.05). Significant differences were observed among groups when analyzing PR and IR according to the 3 embryonic parameters before vitrification. Embryos with 13 to 16 blastomeres yielded the highest PR (39.5%) and IR (24.1 %). The PR and IR of embryos with blastomeres of equal size were significantly higher than those with unequally sized blastomeres (36.5%vs. 21.7%, 23.7%vs. 12.4%,P < 0.05). After warming, embryos with 13 to 16 blastomeres yielded the highest PR and IR (40.9% and 24.2%, respectively). The PR and IR were observed to grow with an increase in the percentage of intact blastomeres (23.2%-38.2%, 14.2%-23.2%).Conclusions: These results show that vitrification methods do not effectively improve survival outcomes for embryos of poor quality and it is needed to develop a comprehensive vitrification protocol that considers all the practical aspects, including the current limitation regarding cleavage-stage embryos of poor quality.展开更多
Objective:The meiotic spindle controls chromosome movement and mediates various functions essential for fertilization and early postfertilization events.This study aimed to examine whether vitrification causes meiotic...Objective:The meiotic spindle controls chromosome movement and mediates various functions essential for fertilization and early postfertilization events.This study aimed to examine whether vitrification causes meiotic damage in vitro-matured metaphase II(MII)human oocytes,and whether the meiotic spindle morphology influences the subsequent developmental outcomes.Methods:The spindle characteristics of MII human oocytes in vitro matured were studied before and after vitrification using PolScope imaging and immunofluorescence staining.The developmental competence of oocytes was also examined.Results:A total of 419 human MII oocytes were obtained from 593 intracytoplasmic sperm injection cycles at our hospital.Of these oocytes,54 were used for immunofluorescence staining,whereas the other oocytes were examined by PolScope imaging and classified into three groups according to the meiotic spindle morphology:(A)normal morphology,(B)weak refraction and short meiotic spindle,and(C)no detectable meiotic spindle.The three groups demonstrated statistically significant differences in terms of survival after vitrification.However,differences were not found in terms of oocyte chromosome structure and meiotic spindle morphology on immunofluorescence staining performed before and after vitrification.Oocyte survival,fertilization,and early embryonic development rates were significantly higher in Group A than in Groups B and C with or without vitrification.While vitrification had no effect on these metrics in Group A,Groups B and C demonstrated significantly lower fertilization and cleavage rates after vitrification/warming.Conclusions:Screening for normal meiotic spindle morphology and chromosome configuration before vitrification may increase the yield of healthy viable oocytes for various assisted reproductive technologies.展开更多
Objective:This study compared spindles,cytoskeleton,and developmental potential between vitrified and slow-frozen oocytes using PolScope and electron microscopy.Methods:Oocytes were randomly divided into control,slow ...Objective:This study compared spindles,cytoskeleton,and developmental potential between vitrified and slow-frozen oocytes using PolScope and electron microscopy.Methods:Oocytes were randomly divided into control,slow freeze-thaw,and vitrification freeze-thaw groups(0,1,and 3 h).PolScope was used to observe spindles,angle of spindles to the first polar bodies,surface areas of oocytes,and lining and outer ret of zona pellucida.Surfaces and ultrastructure of oocytes were observed by scanning electron microscopy and transmission electron microscopy.These measures were used to characterize the impacts of two freezing methods on the developmental capacity of human oocytes.Results:The visible frequency of spindle formation was 92.4%,56.4%,11.2%,24.8%,and 61.1%in control group,slow freeze-thaw group,and the three vitrification freeze-thaw groups(0,1,and 3 h),respectively.Compared to oocytes in the slow freeze group,the angle of the spindle to the first polar body in oocytes in the 3-h vitrification freeze-thaw group was less(37.3°vs.68°,P=0.023).No significant differences were observed between the surface area of oocytes,or lining and outer ret of oocyte zona pellucida between freeze-thaw in these same two groups.Microvilli appeared normal.However,protrusions on oocyte surfaces were increased,and microvilli were laid down on the membrane surface in the 3-h vitrification freeze-thaw group in comparison to the slow-freeze group.Similar comparisons showed better recovery of perivitelline space and mitochondria between the 3-h vitrified and slow-frozen groups.Bipronuclear(2PN)fertilization rate observed in the slow-freeze group(65.7%)was lower than the rate seen in controls(79.2%,P=0.041).No significant differences were observed in 2PN fertilization,cleavage,and blastocyst formation rates between the 3-h vitrification freeze-thaw and control groups.Conclusions:Results suggest that vitrification freeze-thaw for oocyte cryopreservation was a better choice than slow freeze-thaw.展开更多
文摘Objective:To assess the effects of melatonin and/or cysteamineonin vitro maturation, culturing and post-warming of buffalo embryos.Methods: Buffalo oocytes were classified into control, cysteamine (50 μM), melatonin (10 ng/mL) and cysteamine (50 μM) + melatonin (10 ng/mL) treatment groups. In experiment 1, previous treatments were added duringin vitromaturation and culturing of buffalo oocytes.Results:Cleavage and blastocyst rates were significantly (P<0.05) increased in melatonin treated group (70.5±0.9 and 12.8±1.0, respectively). However this effect was potentiated when combined with cysteamine (74.0±1.7 and 14.8±1.7, respectively). In experiment 2, the treatements were added in maturtaion, culturing as well as post-warming culture media. Embryos at 7 d were vitrified.Viability assessement directly after warming showed significant increase (P<0.05) in cysteamine, melatonin and their combination groups (76.8±2.8, 80.0±2.1 and 83.3±1.7, respectively) than control (65.8±2.4);but the viability after 24 h post-warming was the best in cysteamine + melatonin combination group (61.4±2.1).Conculsions: Enriching maturation, culturing and post-warming media of buffalo oocytes and embryos with melatonin and/or cysteamine have significantly beneficial effects on oocyte developmental competence as well as embryos vitrification procedure outcomes which in turn resulting in enhancement of commercial buffalo embryo production.
文摘Objective:To compare the outcomes of vitrification using cryoloop with slow-freezing meth-od for human blastocyst cryopreservation.Methods:In IVF-ET cycles,supernumerary embryos were cultured to Day 5 or Day 6,blas-tocysts were cryopreserved by vitrification using cryoloops or slow-freezing method,then blasto-cyst survival rate and pregnant rate were compared.Results:115 vitrified blastocysts from 39 cycles were warmed,104(90.4%)blastocysts sur-vived.After the transfer of 74 blastocysts in 38 cycles,28(73.7%)women got clinically preg-nant,2(7.1%)of them suffered from miscarriage,2 healthy babies were born in 2 deliveries,and the other 24 pregnancies are ongoing.As to slow-freezing method,87 blastocysts from 21 cy-cles were thawed,37(42.5%)of them survived,28 blastoeysts were transferred in 15 cycles,6(40%)women got clinically pregnant,1 of them miscarried,3 healthy babies were born in 2 de-liveries,and the other 3 pregnancies are ongoing.Conclusion:The survival rate and pregnant rate of vitrification using cryoloop are superior totraditional slow-freezing method,and the transfer cancel rate is lower than that of slow-freezingmethod.The miscarriage rate is similar in two methods.
文摘Bovine oocytes cultured in vitro for 6 hours or 22 hours were cryopreserved in different vitrification solutions (EFS40, EFS50, EDFS30 or EDFS40) by the two-step method with OPS (open pulled straw).The best results were achieved by using EDFS30 to cryopreserve the oocytes either for in vitro fertilization or for chemical activation. The blastocyst rates were 12% and 17% in 6 hour and 22 hour cultures respectively following in vitro fertilization. If frozen-thawed oocytes were continued in culture up to 24 hours, and were activated by chemicals, the blastocyst rates were 22% and 24% in 6-hour and 22-hour groups respectively.There were no statistical differences between frozen and fresh oocytes (P ＞ 0.05).
文摘Background: In order to assess the chromosomal status in embryos obtained from vitrified and fresh donated oocytes, preimplantational genetic diagnostic (PGD) was performed after biopsy of one blastomere at day 3. METHODS: A total of 249 oocytes were obtained from 23 oocyte donors, 80 oocytes were used in the vitrified group and 151 oocytes were used in the fresh group. Nine chromosomes (13, 15, 16, 17, 18, 21, 22, X and Y) were investigated by fluorescence in situ hybridization (FISH) analysis in 56 and 121 embryos from vitrified and fresh group respectively. Fertilization, cleavage rate, embryo quality and chromosomal abnormality rate were compared between groups evaluated. Results: Vitrified oocytes showed a survival rate of 97.5%. There was no significant difference in the fertilization rate (82.7% and 91.4%), Day 2 cleavage rate (90.3% and 87.7%) or blastocyst formation rate (31.1% and 44.6%) for the vitrified and fresh groups respectively. Chromosomal abnormality rate (66.1% versus 71.9%), percentage of abnormal blastocysts (61.1% versus 64.8%) and percentage of abnormalities for each analyzed chromosome were similar for the vitrified group compared with the control group. Conclusions: The rates of chromosomal abnormalities in embryos from vitrified oocytes are similar to those published previously;and comparable to those observed in embryos from fresh oocytes. These results confirm that the developmental competence and chromosomal status of embryos obtained from vitrified oocytes is not affected by the vitrification procedure, and they preserve the potential to be fertilized and to develop in to blastocyst stage similar to embryos from fresh oocytes.
基金funded by EU in the framework of H2020–SFS–2015–2under grant agreement IMAGE–677353–2supported by COST–Action SLAAM–COST–STSM–BM1308–36887。
文摘Background:Currently,there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes.To date,vitrification(VIT)is the most efficient method for pig embryo cryopreservation.Despite a high number of embryos survives in vitro after vitrification/warming procedures,the in vivo embryo survival rates after embryo transfer are variable among laboratories.So far,most studies have focused on cryoprotective agents and devices,while the VIT effects on porcine embryonic gene expression remained unclear.The few studies performed were based on vitrified/warmed embryos that were cultured in vitro(IVC)to allow them to re–expand.Thus,the specific alterations of VIT,IVC,and the cumulative effect of both remained unknown.To unveil the VIT-specific embryonic alterations,gene expression in VIT versus(vs.)IVC embryos was analyzed.Additionally,changes derived from both VIT and IVC vs.control embryos(CO)were analyzed to confirm the VIT embryonic alterations.Three groups of in vivo embryos at the blastocyst stage were analyzed by RNA–sequencing:(1)VIT embryos(vitrified/warmed and cultured in vitro),(2)IVC embryos and(3)CO embryos.Results:RNA–sequencing revealed three clearly different mRNA profiles for VIT,IVC and CO embryos.Comparative analysis of mRNA profiles between VIT and IVC identified 321,differentially expressed genes(DEG)(FDR<0.006).In VIT vs.CO and IVC vs.CO,1901 and 1519 DEG were found,respectively,with an overlap of 1045 genes.VIT-specific functional alterations were associated to response to osmotic stress,response to hormones,and developmental growth.While alterations in response to hypoxia and mitophagy were related to the sum of VIT and IVC effects.Conclusions:Our findings revealed new insights into the VIT procedure-specific alterations of embryonic gene expression by first comparing differences in VIT vs.IVC embryos and second by an integrative transcriptome analysis including in vivo control embryos.The identified VIT alterations might reflect the transcriptional signature of the embryo cryodamage but also the embryo healing process overcoming the VIT impacts.Selected validated genes were pointed as potential biomarkers that may help to improve vitrification.
基金Item supported by international coopera-tion programme of science and technology of Shanghai (No.015407005)
文摘The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.
文摘Objective:To assess effect of buffalo bull breed on the development and cryotolerence of the in vitro produced embryos.Methods: Three types of frozen semen were adopted;Egyptian, Italian and cross-bred (Egyptian-Italian) breeds were used for in-vitro fertilization and vitrification of their embryos. Oocytes were collected from buffalo ovaries and maturedin vitrofor 24 h, then they were fertilized using the three semen breeds. The produced embryos of morula and blastocysts were vitrified using ethylene glycol and dimethyl sulfoxide then evaluated for their viability after warming.Results: The cleavage and blastocysts rates significantly declined in oocytes fertilized by Egyptian (P<0.01) than in Italian (P<0.05) and crossbred (P<0.05) frozen semen. After embryo vitrification, there were no significant differences among the three breeds in the percentages of morphologically viable embryos evaluated directly after warming and at 24 h post-culture. Conclusions:Thein vitro fertilization response to frozen-thawed semen varies between breeds;however, the resistance of produced embryos to the damage effect of vitrification does not vary.
文摘Objective: To assess the developing potentiality of mouse morula produced in vitro or in the after vitrification and to evaluate the effect of one-step and two-step vitrification methods. Method: Mouse morula produced in for and in the were vitrified in the solution containing ethylene glycol, Ficoll and sucrose (EFS solution) with one-step and two-step methods. The developing potential and status of the pellucid zona in vitified mouse morula were assessed. Results: The percentages of morula developed into blastocyst stage were 81. 8% and 82.4%, 97. 3% and 98.4%, respectively, after one-step and two-step exposure of in vitro morula or in vivo morula to EFS solution alone, which did not show significant difference compared to their controls (P > 0. 05). The percentage of in vitro morula developed into blastocyst vitrified by onestep method was significantly lower than that by two-step method and coned (P < 0.05, 70.6% vs 81 .3%; 70.6% vs 83 .6%, respectively). However, there was no significant difference between blastocyst rates of in vivo morula vitrified by one-step and two-step methods (P>0.05, 93. 1% us 95.7%). No rupture of pellucid zona was observed in all thawed morula after one-step and two-step vitrification, irrespective of in vitro morula or in vivo morula. Conclusion: Morula produced in vitro and in vivo after vitrification may maintain high survival rate and developing potential. Two-step vitrification method with EFS solution is suitable for in vitro morula, which can improve the developing potential of in vitro morula. Onestep and two-step vitrification method have no detrimennd effect on the developing potential of in vivo morula.
文摘Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.
文摘Vitrification of immature oocytes at the germinal vesicle (GV) stage is important to preserve female gametes. The standard formula for vitrification solutions has long been a debate. Herein, we investigated the effect of the presence or absence of trehalose in vitrification solution on viability, in vitro maturation (IVM) rates, and development of vitrified/warmed immature dromedary camel oocytes. Cumulus oocyte complexes (COCs) obtained at slaughter from the ovaries of mature she-camels were randomly allocated into three groups;namely, control group, oocytes were directly subjected to IVM without vitrification, vitrification solution 1 (VS1) group, oocytes were vitrified in a solution composed of 25% ethylene glycol (EG) plus 25% dimethyl sulfoxide (DMSO) + 0.5 M trehalose;and vitrification solution 2 (VS2) group, oocytes were vitrified in a solution composed of 25% EG plus 25% DMSO. Vitrification of COCs was conducted by open pulled straws (OPS) method. Following vitrification and warming, morphologically viable oocytes were matured in vitro for 36 h. COCs were then fertilized and cultured in vitro for 7 days. The percentage of viable oocytes was significantly higher (P 0.05) in VS2 than VS1 group (80.0% vs. 63.3%, respectively). Nuclear maturation, cleavage (48 h post-insemination;pi), and blastocyst rates (7 days pi) were significantly higher (P < 0.05) in VS2 than in VS1 groups. No significant differences were observed in oocyte maturation and development rates between VS2 and control groups. In conclusion, vitrification of immature dromedary camel oocytes in trehalose-free solution (VS2) was more advantageous than that in trehalose supplemented media since it did not reduce viability and development.
文摘Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.
文摘Is there a really need to validate oocyte vitrification technique in an ART laboratory before establishing it in daily practice? Validation of micromanipulationbased technique, in this case oocyte vitrification, is essential prior to enlarging its use to routine practice. Oocyte vitrification is a new worldwide used technique and legal recently inFrance. This micromanipulation needs to be performed by a skilled and experienced embryologist and requires an internal assessment in each ART unit before any wide use. We designed a prospective study, from September 2011 to July 2012, using sibling oocytes from women who recovered more than 12 Metaphase II oocytes. A part of freshly recovered oocytes underwent immediate ICSI while the remaining oocytes were vitrified. 87 couples undergoing ICSI were selected based on number of mature oocytes available on the recovery day after denudation. A part of fresh MII oocytes were microinjected and the others were vitrified using an open system (Cryotop?). The major criterion of interest was the number of embryo transferred/ number of Metaphase II ratio for after ICSI on fresh oocytes (42/211) versus vitrified/warmed oocytes (51/204) (p > 0.05). Secondary studied criteria were survival rate (80.5% ± 26.3%), fertilization rate (68.9 ± 33.5) and finally, cumulative pregnancy rate obtained in this study is 40.2%. One of the benefits of such practice is the limitation of embryo freezing. However, the study design delays oocytes warming cycles, due to pregnancies triggered by the transfer of fresh derived oocyte embryos and to the priority to transfer all the frozen embryos before starting oocytes warming. Moreover, no data is available about children’ health. Oocyte vitrification represents not only a change in our daily practice to improve cumulative pregnancy rate but also a promising tool to develop egg banking and donation. Clinical Trials Registration number: 209 R02.
基金supported by grants from the National Key Research and Development Program(Nos.2017YFC1002000,2018YFC1004001,and 2016YFC1000600)the National Natural Science Foundation of China(Nos.81571386 and 31429004)the Capital Health Development Research Project(No.2018-2-4095).
文摘Oocyte cryopreservation is widely used for clinical and social reasons.Previous studies have demonstrated that conventional slow-freezing cryopreservation procedures,but not storage time,can alter the gene expression profiles of frozen oocytes.Whether vitrification procedures and the related frozen storage durations have any effects on the transcriptomes of human metaphase Ⅱ oocytes remain unknown.Four women(30–32 years old)who had undergone IVF treatment were recruited for this study.RNA-Seq profiles of 3 fresh oocytes and 13 surviving vitrified-thawed oocytes(3,3,4,and 3 oocytes were cryostored for 1,2,3,and 12 months)were analyzed at a single-cell resolution.A total of 1987 genes were differentially expressed in the 13 vitrifiedthawed oocytes.However,no differentially expressed genes were found between any two groups among the 1-,2-,3-,and 12-month storage groups.Further analysis revealed that the aberrant genes in the vitrified oocytes were closely related to oogenesis and development.Our findings indicated that the effects of vitrification on the transcriptomes of mature human oocytes are induced by the procedure itself,suggesting that long-term cryostorage of human oocytes is safe.
文摘CRYOPRESERVATION by vitrification is a new ultralow-temperature-storage technique developed in the 1980s. Operationally, procedures for vitrification of biological specimens consist of the following basic steps: treatment of the samples in a highly concentrated vitrification solution and then plunging the specimens into liquid nitrogen. The word 'vitrification' is sometimes used to describe the high moisture of the in vitro cultures or regenerants. However, in this note, this word means a biophysical process in which the cells and the solution are transformed into a homogeneous and amorphous state. The water in cells does not change into ice, but in
基金This work was supported by National Natural Science Foundation of China(No.31472054)the National Key Research and Development Program of China(2016YFC1000600).
文摘Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice.However,it has been shown to have a negative impact on sperm function and structure.Vitrification as a successful alternative method has been proved to have better protective effects on human embryos,but vitrification of spermatozoa is still subject to low recovery rates.In this study,a modified vitrification method for native spermatozoa was developed.A total of 28 semen samples were included;each sample was divided into three equal parts and assigned to fresh,slow freezing,and vitrification groups.Sperm vitality,motility,morphology,DNA integrity,and acrosome reaction were assessed for each of the groups.The results showed that vitrification achieves better results for several sperm protection parameters than slow freezing;vitrification achieves a higher recovery rate(P<0.05),motility(P<0.05),morphology(P<0.05),and curve line velocity(P<0.05)than slow freezing.Furthermore,DNA fragmentation was decreased(P<0.05)and better acrosome protection(P<0.05)was exhibited in the spermatozoa after vitrification.Principal component analysis of all sperm parameters revealed that the vitrification cluster was closer to the fresh cluster,indicating that spermatozoa are better preserved through vitrification.In conclusion,while both slow freezing and vitrification have negative effects on sperm function and structure,the vitrification protocol described here had a relatively better recovery rate(65.8%)and showed improved preservation of several sperm quality parameters compared with slow freezing.
基金This work was supported by the China National Key R&D Program(2018YFC1004001)the Research Units of Comprehensive Diagnosis and Treatment of Oocyte Maturation Arrest(2019-I2M-5-001)the Special Research Project of Chinese Capital Health Development(2018-2-4095).
文摘Objective: To evaluate the effect of morphologic factors on survival rate (SR), pregnancy rate (PR), and implantation rate (IR) of human embryo vitrification following frozen embryo transfer (FET) on day 3 post-ovulation.Methods: Women undergoing FET (n = 921) with embryos cryopreserved by vitrification between 2012 and 2013 were enrolled in this retrospective cohort study.Results: Embryos with >9 blastomeres yielded the highest SR of 100%. Lower SR was observed in embryos with 5 to 6 (57.5%) and 4 blastomeres (41.4%). In terms of blastomere symmetry, the SR of embryos with equally sized blastomeres was significantly higher than that of embryos with unequally sized cells (82.5%vs. 64.6%,P < 0.05). As fragmentation increased, SR decreased from 92.1% to 20.6% (P < 0.05). Significant differences were observed among groups when analyzing PR and IR according to the 3 embryonic parameters before vitrification. Embryos with 13 to 16 blastomeres yielded the highest PR (39.5%) and IR (24.1 %). The PR and IR of embryos with blastomeres of equal size were significantly higher than those with unequally sized blastomeres (36.5%vs. 21.7%, 23.7%vs. 12.4%,P < 0.05). After warming, embryos with 13 to 16 blastomeres yielded the highest PR and IR (40.9% and 24.2%, respectively). The PR and IR were observed to grow with an increase in the percentage of intact blastomeres (23.2%-38.2%, 14.2%-23.2%).Conclusions: These results show that vitrification methods do not effectively improve survival outcomes for embryos of poor quality and it is needed to develop a comprehensive vitrification protocol that considers all the practical aspects, including the current limitation regarding cleavage-stage embryos of poor quality.
基金Natural Science Foundation of China(No.81601342,81901558)from Dr.Yi-Juan Sun and Rui-huan GuShanghai Municipal Planning Commission of Science and Research Fund(General Program,No.201740075)Huangpu District,Shanghai Municipal Planning Commission of Science and Research Fund(No.HKW201659).
文摘Objective:The meiotic spindle controls chromosome movement and mediates various functions essential for fertilization and early postfertilization events.This study aimed to examine whether vitrification causes meiotic damage in vitro-matured metaphase II(MII)human oocytes,and whether the meiotic spindle morphology influences the subsequent developmental outcomes.Methods:The spindle characteristics of MII human oocytes in vitro matured were studied before and after vitrification using PolScope imaging and immunofluorescence staining.The developmental competence of oocytes was also examined.Results:A total of 419 human MII oocytes were obtained from 593 intracytoplasmic sperm injection cycles at our hospital.Of these oocytes,54 were used for immunofluorescence staining,whereas the other oocytes were examined by PolScope imaging and classified into three groups according to the meiotic spindle morphology:(A)normal morphology,(B)weak refraction and short meiotic spindle,and(C)no detectable meiotic spindle.The three groups demonstrated statistically significant differences in terms of survival after vitrification.However,differences were not found in terms of oocyte chromosome structure and meiotic spindle morphology on immunofluorescence staining performed before and after vitrification.Oocyte survival,fertilization,and early embryonic development rates were significantly higher in Group A than in Groups B and C with or without vitrification.While vitrification had no effect on these metrics in Group A,Groups B and C demonstrated significantly lower fertilization and cleavage rates after vitrification/warming.Conclusions:Screening for normal meiotic spindle morphology and chromosome configuration before vitrification may increase the yield of healthy viable oocytes for various assisted reproductive technologies.
基金supported by grants from the National Natural Science Foundation of China(No.81701419 and No.81571418).
文摘Objective:This study compared spindles,cytoskeleton,and developmental potential between vitrified and slow-frozen oocytes using PolScope and electron microscopy.Methods:Oocytes were randomly divided into control,slow freeze-thaw,and vitrification freeze-thaw groups(0,1,and 3 h).PolScope was used to observe spindles,angle of spindles to the first polar bodies,surface areas of oocytes,and lining and outer ret of zona pellucida.Surfaces and ultrastructure of oocytes were observed by scanning electron microscopy and transmission electron microscopy.These measures were used to characterize the impacts of two freezing methods on the developmental capacity of human oocytes.Results:The visible frequency of spindle formation was 92.4%,56.4%,11.2%,24.8%,and 61.1%in control group,slow freeze-thaw group,and the three vitrification freeze-thaw groups(0,1,and 3 h),respectively.Compared to oocytes in the slow freeze group,the angle of the spindle to the first polar body in oocytes in the 3-h vitrification freeze-thaw group was less(37.3°vs.68°,P=0.023).No significant differences were observed between the surface area of oocytes,or lining and outer ret of oocyte zona pellucida between freeze-thaw in these same two groups.Microvilli appeared normal.However,protrusions on oocyte surfaces were increased,and microvilli were laid down on the membrane surface in the 3-h vitrification freeze-thaw group in comparison to the slow-freeze group.Similar comparisons showed better recovery of perivitelline space and mitochondria between the 3-h vitrified and slow-frozen groups.Bipronuclear(2PN)fertilization rate observed in the slow-freeze group(65.7%)was lower than the rate seen in controls(79.2%,P=0.041).No significant differences were observed in 2PN fertilization,cleavage,and blastocyst formation rates between the 3-h vitrification freeze-thaw and control groups.Conclusions:Results suggest that vitrification freeze-thaw for oocyte cryopreservation was a better choice than slow freeze-thaw.
