ICSI导致小鼠胚胎雄原核H3K9甲基化异常以及胚胎发育迟缓

ICSI causes abnormal H3K9 methylation in the male pronuclei and growth retardation of mouse embryos

目的:以小鼠为模型,评估卵细胞胞质内单精子注射(ICSI)技术的安全性。方法:模拟临床ICSI技术,通过孤雌激活、免疫荧光、胚胎移植、早期植入点检测、中期顶臀径检测等实验方法综合评估该技术。结果:ICSI导致小鼠植入前胚胎发育能力显著下降,尤其是8细胞之后的胚胎发育率下降极显著(P<0.01),而且在ICSI胚胎的雄原核上检测到异常的H3K9双甲基化荧光。进一步检测移植后的ICSI胚胎发育情况,结果显示,与对照(正常受精)相比,E5.5 d早期植入率无显著差异(P=0.6),但是E9.5 d的"正常胚胎"百分率却显著降低(P<0.01),即使在这些"正常的ICSI胚胎"中也出现了高比例的发育滞后现象。结论:ICSI有可能通过对雄原核H3K9双甲基化的影响进而影响胚胎生长发育。

Objective： To evaluate the safety of intracytoplasmic sperm injection （ICSI） in the mouse model. Methods： We simulated clinical ICSI technology and comprehensively evaluated it by parthenogenetic activation, immunofluorescence, embryo trans- plantation, examination of early implantation, and measurement of the crown-rump length （CRL）. Results： ICSI significantly re- duced the ability of preimplantation embryo development of the mouse, especially after the 8-cell stage （P 〈 O. 01 ）. The fluorescence of H3K9 dimethylation was abnormal at the male pronuclei of the embryos derived from ICSI. Further examination of the development of the transferred ICS! embryos indicated no significant difference in the rate of early implantation at E5.5 days as compared with normal fertilization （ P = O. 6） , but the percentage of ＂normal embryos＂ was decreased significantly at E9.5 days （P 〈 0. 01 ）. Obvious growth retardation phenotype was observed even in the normal ICSI embryos at E9.5 days. Conclusion ： ICSI might result in growth retarda- tion of embryos by affecting H3K9 dimethylation in the male pronuclei.