牛体外受精时老化卵对受精率与染色体异常发生的影响

Effects of Egg aging In vitro Maturation on Fertilizability and Chromosomal Aberrations in Bovine Oocytes after In vitro Fertilization

通过延长体外培养时间得到牛老化卵 ,对其体外受精率与染色体的异常发生进行了研究。体外受精 4 8h后的受精率 ,4 6 h培养组与 2 2 h和 34 h培养组之间差异显著 ( P<0 .0 5)。随着老化时间的延长 ,受精率及胚胎发育速度明显降低。染色体分析结果表明 ,4 6 h组的受精卵的染色体异常发生率为 6 1 .6 % ,2 2 h组4 4.6 % ,2组之间差异显著 ( P<0 .0 5)。单倍体 ( n=30 )的发生率也随着老化时间的延长而增加。这些单倍体的性染色体的构成表明 ,含有 X-性染色体的胚的出现率显著高于含有 Y-染色体的胚的出现率 ( P<0 .0 5)。单倍体的发生是由卵的老化而引起单一配子的孤雌发生。体外培养时间的延长对正常的

Effects of egg aging were examined in bovine oocytes which were fertilized in vitro after aging in vitro maturation.At 48 h after insemination,the cleavage rates in the 46 h group was significantly lower than in 22 h and 34 h groups.It appears that the developmental speed of aged eggs would decline with the in vitro maturation time of bovine oocytes.By analyzing the chromosomes of embryos,the chromosomal aberrations in 46 h group(61 6%) was significantly higher than that in 22 h group(44 6%).The longer eggs aging resulted in further incidence of haploid.Each proportion of haploid eggs with X chromosome in dividual groups were significantly higher than that of Y chromosome.The morphology of chromosomes in these haploids resembled those of uniform haploids in parthenogenetically activated eggs.Therefore,the haploids were judged to be resultant from the parthenogenetic activation of eggs by aging.There was no eggs aging effect on the sex ratio of the bovine eggs fertilized in vitro either.