In this work, we have considered a new multimodality imaging for macroscopy based on Second Harmonic Generation (SHG) method to monitor invasivelessly the matrix collagen. As the triple helicoidally structure of colla...In this work, we have considered a new multimodality imaging for macroscopy based on Second Harmonic Generation (SHG) method to monitor invasivelessly the matrix collagen. As the triple helicoidally structure of collagen molecules appearing as not centrosymetric, very organized and spatially oriented, collagen fibrils give rise to a very strong SHG signal and can be imaged without any exogenous dye. To integrate a multidimensional scale with a large field of view (non-sliced samples), we have adapted and validated an instrumental coupling between a two photon excitation laser and a macroscope to collect cartography of SHG signal. We introduced an index (F-SHG) based on decay time response measured by TCSPC for respectively Fluorescence (F) and Second Harmonic Generation (SHG) values. For various sample where protein collagen is the major component of extracellular matrix (vessel, skin, carotide vessel, rat femoral head cartilage, mouse tumor, human wharton’s jelly and rat tendon) or not (nacre), we compared the index distribution obtained with MacroSHG. In this work, we showed for the first time that multiscale large field imaging (Macroscopy) combined to Multimodality approaches (SHG-TCSPC) could be an innovative and non-invasive technique to detect and identify some biological interest molecules (collagen) in biomedical topics.展开更多
The aim of this work was to develop an in vitro model to study mechanical compression effects on cartilage. A pressure-controlled compression device was used in this study. Cartilage explants obtained from human knee ...The aim of this work was to develop an in vitro model to study mechanical compression effects on cartilage. A pressure-controlled compression device was used in this study. Cartilage explants obtained from human knee were compressed at 1MPa/1Hz for 7 hours (30 min ON, 30 min OFF) under normoxia (5% CO2, 21% O2) or hypoxia (5% CO2, 5% O2). Cell viability was analyzed while nitric oxide (NO) and glycosaminoglycans (GAG) release was assayed in culture media. Mechanical stimulation increased NO production and GAG release by human cartilage explants under normoxia and hypoxia culture. In normoxia and hypoxia conditions, mechanical stimulation alters human OA cartilage metabolism. There is also, an increase in matrix degradation after compression, as shown by levels of GAG found in culture media. This study put in evidence the importance of mechanical compression in the progression of the osteoarthritis and present and in vitro model for mechanobiological and pharmacological studies.展开更多
Peripheral nerve regeneration requires stepwise and well-organized establishment of microenvironment.Since local delivery of VEGF-A in peripheral nerve repair is expected to promote angiogenesis in the microenvironmen...Peripheral nerve regeneration requires stepwise and well-organized establishment of microenvironment.Since local delivery of VEGF-A in peripheral nerve repair is expected to promote angiogenesis in the microenvironment and Schwann cells(SCs)play critical role in nerve repair,combination of VEGF and Schwann cells may lead to efficient peripheral nerve regeneration.VEGF-A overexpressing Schwann cells were established and loaded into the inner wall of hydroxyethyl cellulose/soy protein isolate/polyaniline sponge(HSPS)conduits.When HSPS is mechanically distorted,it still has high durability of strain strength,thus,can accommodate unexpected strain of nerve tissues in motion.A 10 mm nerve defect rat model was used to test the repair performance of the HSPS-SC(VEGF)conduits,meanwhile the HSPS,HSPS-SC,HSPS-VEGF conduits and autografts were worked as controls.The immunofluorescent co-staining of GFP/VEGF-A,Ki67 and MBP showed that the VEGF-A overexpressing Schwann cells could promote the proliferation,migration and differentiation of Schwann cells as the VEGF-A was secreted from the VEGF-A overexpressing Schwann cells.The nerve repair performance of the multifunctional and flexible conduits was examined though rat behavioristics,electrophysiology,nerve innervation to gastrocnemius muscle(GM),toluidine blue(TB)staining,transmission electron microscopy(TEM)and NF200/S100 double staining in the regenerated nerve.The results displayed that the effects on the repair of peripheral nerves in HSPS-SC(VEGF)group was the best among the conduits groups and closed to autografts.HSPS-SC(VEGF)group exhibited notably increased CD31+endothelial cells and activation of VEGFR2/ERK signaling pathway in the regenerated nerve tissues,which probably contributed to the improved nerve regeneration.Altogether,the comprehensive strategy including VEGF overexpressing Schwann cells-mediated and HSPS conduit-guided peripheral nerve repair provides a new avenue for nerve tissue engineering.展开更多
文摘In this work, we have considered a new multimodality imaging for macroscopy based on Second Harmonic Generation (SHG) method to monitor invasivelessly the matrix collagen. As the triple helicoidally structure of collagen molecules appearing as not centrosymetric, very organized and spatially oriented, collagen fibrils give rise to a very strong SHG signal and can be imaged without any exogenous dye. To integrate a multidimensional scale with a large field of view (non-sliced samples), we have adapted and validated an instrumental coupling between a two photon excitation laser and a macroscope to collect cartography of SHG signal. We introduced an index (F-SHG) based on decay time response measured by TCSPC for respectively Fluorescence (F) and Second Harmonic Generation (SHG) values. For various sample where protein collagen is the major component of extracellular matrix (vessel, skin, carotide vessel, rat femoral head cartilage, mouse tumor, human wharton’s jelly and rat tendon) or not (nacre), we compared the index distribution obtained with MacroSHG. In this work, we showed for the first time that multiscale large field imaging (Macroscopy) combined to Multimodality approaches (SHG-TCSPC) could be an innovative and non-invasive technique to detect and identify some biological interest molecules (collagen) in biomedical topics.
文摘The aim of this work was to develop an in vitro model to study mechanical compression effects on cartilage. A pressure-controlled compression device was used in this study. Cartilage explants obtained from human knee were compressed at 1MPa/1Hz for 7 hours (30 min ON, 30 min OFF) under normoxia (5% CO2, 21% O2) or hypoxia (5% CO2, 5% O2). Cell viability was analyzed while nitric oxide (NO) and glycosaminoglycans (GAG) release was assayed in culture media. Mechanical stimulation increased NO production and GAG release by human cartilage explants under normoxia and hypoxia culture. In normoxia and hypoxia conditions, mechanical stimulation alters human OA cartilage metabolism. There is also, an increase in matrix degradation after compression, as shown by levels of GAG found in culture media. This study put in evidence the importance of mechanical compression in the progression of the osteoarthritis and present and in vitro model for mechanobiological and pharmacological studies.
基金This work was supported by the National Natural Science Foundation of China(Grant No.:NSFC 81871493,81871503)the Medical Science Advancement Program(Clinical Medicine)of Wuhan University(Grant No.:TFLC2018002,2018003)。
文摘Peripheral nerve regeneration requires stepwise and well-organized establishment of microenvironment.Since local delivery of VEGF-A in peripheral nerve repair is expected to promote angiogenesis in the microenvironment and Schwann cells(SCs)play critical role in nerve repair,combination of VEGF and Schwann cells may lead to efficient peripheral nerve regeneration.VEGF-A overexpressing Schwann cells were established and loaded into the inner wall of hydroxyethyl cellulose/soy protein isolate/polyaniline sponge(HSPS)conduits.When HSPS is mechanically distorted,it still has high durability of strain strength,thus,can accommodate unexpected strain of nerve tissues in motion.A 10 mm nerve defect rat model was used to test the repair performance of the HSPS-SC(VEGF)conduits,meanwhile the HSPS,HSPS-SC,HSPS-VEGF conduits and autografts were worked as controls.The immunofluorescent co-staining of GFP/VEGF-A,Ki67 and MBP showed that the VEGF-A overexpressing Schwann cells could promote the proliferation,migration and differentiation of Schwann cells as the VEGF-A was secreted from the VEGF-A overexpressing Schwann cells.The nerve repair performance of the multifunctional and flexible conduits was examined though rat behavioristics,electrophysiology,nerve innervation to gastrocnemius muscle(GM),toluidine blue(TB)staining,transmission electron microscopy(TEM)and NF200/S100 double staining in the regenerated nerve.The results displayed that the effects on the repair of peripheral nerves in HSPS-SC(VEGF)group was the best among the conduits groups and closed to autografts.HSPS-SC(VEGF)group exhibited notably increased CD31+endothelial cells and activation of VEGFR2/ERK signaling pathway in the regenerated nerve tissues,which probably contributed to the improved nerve regeneration.Altogether,the comprehensive strategy including VEGF overexpressing Schwann cells-mediated and HSPS conduit-guided peripheral nerve repair provides a new avenue for nerve tissue engineering.
