Relationships between in vitro maturation of follicular oocytes and incidences of chrormosomal abnormalities in resultant embryos

本研究由两部分组成：一部分是小鼠体外受精的结果，另一部分是牛体外受精的结果。(1)卵泡卵体外成熟后体外受精小鼠胚胎的细胞遗传学和胚胎学分析卵泡卵母细胞于排卵前hCG后9、10、11和12小时采集小鼠卵泡卵母细胞，孵育至hCG后16小时（卵泡卵母细胞组：F9、F10、F11和F12）。授精后17h取第一次卵裂卵的染色体，94h取胚泡和桑葚胚的染色体。F9 ~ F12组第一次卵裂时多倍体胚胎异常发生率高于对照组。(2)未成熟卵母细胞体外受精牛胚胎的染色体分析对卵母细胞体外成熟不足（12h）的体外受精牛胚胎进行染色体分析。在体外受精后48小时，对照组的大多数胚胎发育为8或16个细胞阶段，而12小时组的许多胚胎发育为2或4个细胞阶段。12 h组染色体异常胚的发生率显著高于26 h组。这些染色体异常为单倍体、多倍体和混合倍体。

The present study consists of two parts : one is the results derived from mouse in vitro fertilization (IVF) and another is the results derived from bovine IVF.(1)Cytogenetical and embryological analyzes in mouse embryos derived from in vitro fertilization following in vitro maturation of follicular oocytesFollicular mouse oocytes were harvested at 9, 10, 11 and 12h after hCG before ovulation, and they were incubated until 16h after hCG (follicular oocyte groups : F9, F10, F11 and F12). Chromosome samples of eggs at the first cleavage division were made at 17h after insemination, and those of morulae and blastocysts were made at 94h. Incidences of abnormal polyploidy embryos at the first cleavage division in the F9 to F12 groups were higher than that of the control group.(2)Chromosomal analysis in bovine embryos derived from in vitro fertilization of immature oocytesChromosomal analysis was accomplished in bovine embryos derived from IVF after insufficient in vitro maturation (12h) of oocytes. At forty-eight hrs after IVF, most of the embryos in the control group developed into the 8-or 16-cell stages, while many embryos in the 12-h group were at the 2-or 4-cell stage. The incidence of chromosomal abnormal embryos in the 12-h group was significantly higher than that in the 26-h group. These chromosomal anomalies were haploids, polyploids and mixoploids.