Effects Of Maternal Hyperhomocysteinemia On Early Embryo Development And Epigenetic Changes

OBJECTIVE: To explore the effects of maternal hyperhomocysteinemia on early embryo development and epigenetic changes METHODS: Six-week-old C57/BL6 female mice were fed with 3% methioninecontaining animal feed for 6 weeks to establish a homocysteinemia mouse model.The blood value of the mice was >17 umol/L.The successfully modeled mice were subjected to superovulation after in vitro fertilization and in vitro embryo culture by PMSG+HCG sequential promotion method.The development rate of embryos at different stages was observed and recorded,blastocysts were collected,and ovarian tissues of model rats were harvested.In addition,modeled mice were subjected to cage experiments,and some were used for litter count live births;some were taken at 14.5 dpc for female fetal ovaries for detecting embryonic development,epigenetic reprogramming and homocysteine metabolism key gene expression levels.RESULTS: The blastocyst formation rate of the hyperhomocysteinemia group(50.6 %)was significantly lower than that of the normal group(75.5%),There was a statistically significant difference between the two groups(p<0.05).The methylation level of blastocysts in the homocysteine group was lower than that in the normal group,and the expression levels of the two proteins DNMT1 and DPPA3,which are closely related to methylation reprogramming,were lower than those in the normal group.The expression level of key genes related to homocysteine metabolism in the ovary of the model group(F0)was up-regulated,while the expression level of the pathway-related genes in the model group of 14.5dpc(F1)ovary did not change significantly.The expression of DNMT1 and DPPA3,two key proteins closely related to apparent reprogramming,was down-regulated in model group(F0)and 14.5dpc(F1)ovary,and the expression of key genes OCT4 and SOX2 involved in embryo development was down-regulated in 14.5dpc(F1)ovary.The number of live births in the hyperhomocysteinemia group(4.2±1.9)was lower than that in the normal group(7.6±1.7),and there was significant difference between the two groups(P<0.05).