摘要
奶牛冷冻胚胎移植成活率较鲜胚移植明显低。为明确低温冷冻造成胚胎损伤的机理、为冷冻保存方法的进一步改进提供理论依据,利用透射电子显微镜观察了奶牛胚胎常规冷冻和玻璃化冷冻前后的超微结构变化。结果表明,奶牛鲜胚细胞分为两种类型:一种位于内细胞团(ICM)外层,胞质电子致密度低而着色浅,并含有大量的线粒体和内质网;另一种位于ICM中心区域,着色较深,溶酶体的数量多,其余细胞器较少。常规冷冻后,透明带和卵周隙明显变宽,细胞间接触变得松散。囊胚中含有退化的胞核和凋亡小体,内质网变大、变粗,脂滴明显增多。玻璃化冷冻后,ICM细胞的结构发生破坏,部分细胞发生崩解,细胞碎片大量分布于细胞间隙和卵周隙中,并可见大量的脂滴,凋亡细胞和凋亡小体增多。冷冻过程对早期胚胎细胞器的损伤可能是移植后成活率下降的主要原因。
The objective of present study was to investigate the influence of conventional slow freezing and vitrification on the morphology of early bovine embryos. By the transmission electron microscope ,two types of cells with different electron-density of their cytoplasm in the bovine morulae were observed. One appeared light in color with low electron-density cytoplasm,and possessed numerous cellular organelles such as Mi and Er and had microvilli projecting into the perivitelline space （PvS）. The other was stained more densely and generally possessed fewer organelles, but more lysosome-like structures in the cytoplasm than that of the former cells. The embryos experienced conventional slow freezing were characterized by the wider zona pellucida and perivitelline space of morulae cells, the decrease in the number of junctional contacts among the cells, and the increase in the number of degenerated nuclei and apop- totic-like bodies as well as considerable amounts of debris and lipid droplets in the intracellular space and PvS. The embryos frozen by vitrification showed a more severe morphological damages. The structures of peripheral layer cell,ICM cells,and junctions or intracellular connections were all unrecognizable. Otherwise,a lot of cellular debris in the intercellular space and PvS, as well as incresing apoptotic cells or apoptotic bodies,could be found after vitrification freezing. It was concluded that the inferior morphology in the frozen early embryo cells may be responsible for the low survival rate commonly occured after implanting.
出处
《中国草食动物》
CAS
2009年第4期13-16,共4页
China Herbivores
基金
广东海洋大学博士启动基金(0712107)
关键词
奶牛
胚胎冷冻
超微结构
dairy cow
embryo cryopreservation
ultrastructure
