血清及BSA对牛体外受精胚胎发育过程超微结构影响的研究

EFFECTS OF FCS AND BSA ON ULTRASTRUCTURE OF IN VITRO PRODUCED BOVINE EMBRYOS

本研究将牛IVF胚胎分别在SOF+FCS、SOF+BSA和SOF+PVA三种培养系统内进行培养,然后分别取三个系统中发育到原核期、2细胞、4细胞、8细胞、桑椹胚和囊胚阶段的胚胎进行透射电镜的观察,了解培养系统中血清和BSA的添加与否对胚胎发育过程中细胞内脂滴、细胞连接、细胞凋亡和微绒毛发育的影响.观察结果表明:各培养系统胚胎的细胞质中均存在大量的脂滴,表明外培养系统是造成脂滴积累的主要原因;血清的添加不会进一步促进脂滴的大量积累,反而可以避免多个脂滴聚合成更大的脂滴.三种培养系统条件下胚胎细胞连接无显著差异.培养系统中添加FCS或BSA时,桑椹胚期以后的胚胎细胞中存在凋亡小体,表明血清成分是引起细胞凋亡的重要原因.培养系统中血清成分的缺乏会影响胚胎表面微绒毛的发育.

Bovine IVF embryos were cultured in SOF+ FCS,SOF+ BSA and SOF+ PVA respectively. The embryos at 2-cell,4-cell,8-cell stage embryos, morulae and blastocysts from each culture system were collected and prepared for observation in transmission electron microscope, so that to understand the effects of the supplement of serum or BSA or not in culture system on the ultrastructure of embryos. It was observed that many lipid droplets existed in the cytoplasm of embryos cultured in every system at whole developmental stage, and the results indicated that the accumulation of cytoplasmic lipid droplets was mainly caused by the in vitro culture condition. The supplement of serum in culture system did not further promoted the accumulation of lipid droplets,on the contrary could avoided the integration of many droplets to bigger ones. There was no significant difference on cell junction of embryos cultured in different system. Apoptotic bodies were observed in morulae and blastocysts in the embryos cultured in SOF+ FCS and SOF+ BSA, this result showed that the apoptosis in embryo cells was mainly caused by the composition in serum. The development of microvillis on the surface of embryo could be affected with the lacking of serum or BSA in the culture system.