Dorland M, Duijndam W A, Kruip T A, van der Donk J A
Department of Cell Biology and Histology, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands.
J Reprod Fertil. 1993 Nov;99(2):681-8. doi: 10.1530/jrf.0.0990681.
A Feulgen staining procedure that stains the DNA of individual fixed nuclei stoichiometrically was used to analyse cytophotometrically the incidence of total ploidy and mixoploidy in 28 day-7 bovine embryos that had been fixed after collection ('non-cultured' embryos). The influence of culture on the incidence of chromosome abnormalities was further studied in another group of 24 embryos ('cultured' embryos) by culturing them for 24 h in Whittingham's medium. Of the total 52 embryos studied, two appeared to be entirely abnormal: one embryo was completely haploid, whereas the other embryo was completely triploid. Individual hyperdiploid nuclei and hypodiploid nuclei were frequently observed in the otherwise diploid embryos. As haploid polar bodies can still be present in morulae and blastocysts (to a maximum of three), only embryos with more than three hypodiploid nuclei were considered as abnormal. Of the 'non-cultured' embryos, 33.3% had one or more hyperdiploid nuclei, whereas 51.9% had more than three hypodiploid nuclei. In this latter group, 35.7% of the embryos also had hyperdiploid nuclei. The results also showed that day-7 bovine embryos that are completely haploid, completely triploid or mixoploid cannot be detected only by examining their morphology. It is concluded that the incidence of, especially, mixoploidy in embryos can be better studied by measuring the DNA content of the individual nuclei of an embryo rather than by analysing chromosomes, as in the latter method only dividing cells can be analysed. The presence of hyperdiploid and hypodiploid nuclei may indicate the frequent occurrence of mitotic segregation failures during mitosis in bovine embryos.(ABSTRACT TRUNCATED AT 250 WORDS)
采用福尔根染色程序对单个固定细胞核的DNA进行化学计量染色，通过细胞光度法分析了28枚采集后固定的第7天牛胚胎（“未培养”胚胎）中整倍体和混倍体的发生率。在另一组24枚胚胎（“培养”胚胎）中，通过在惠廷厄姆培养基中培养24小时，进一步研究培养对染色体异常发生率的影响。在所研究的52枚胚胎中，有两枚似乎完全异常：一枚胚胎完全是单倍体，而另一枚胚胎完全是三倍体。在其他方面为二倍体的胚胎中经常观察到单个超二倍体核和亚二倍体核。由于桑葚胚和囊胚中仍可能存在单倍体极体（最多三个），因此只有具有三个以上亚二倍体核的胚胎才被视为异常。在“未培养”胚胎中，33.3%有一个或多个超二倍体核，而51.9%有三个以上亚二倍体核。在后一组中，35.7%的胚胎也有超二倍体核。结果还表明，仅通过检查形态无法检测出完全单倍体、完全三倍体或混倍体的第7天牛胚胎。得出的结论是，尤其是胚胎中的混倍体发生率，通过测量胚胎单个细胞核的DNA含量比分析染色体能得到更好的研究，因为在后一种方法中只能分析正在分裂的细胞。超二倍体和亚二倍体核的存在可能表明牛胚胎有丝分裂期间有丝分裂分离失败频繁发生。（摘要截短于250字）
