The Study Of Histone Methylase MLL1 In Endometrium During Embryo Peri-implantation

PartⅠ Expression profiles of MLL1 and HOXA10 in endometrium of infertility Objective To analyse the expression of MLL1 and HOXA10 in human endometrium during different period of menstrual cycle.Methods Fresh endometrium tissues in proliferated and secretary phase of the normal menstrual cycle were collected from 30 patients in Reproductive Center of Zhongnan Hospital Wuhan University,the average age of patients is 30±5.1 years old.RT-PCR was used to investigate the expression level of MLL1 and HOXA10 m RNA,and immunohistochemistry was used to detected the expression of MLL1 and HOXA10 protein in different period of normal menstrual cycle.Results RT-PCR showed that the expression level of MLL1 and HOXA10 m RNA in secretary phase were higher than those in proliferated phase(P<0.05);the results of immunohistochemistry detected that MLL1 and HOXA10 protein were mainly located in the luminal and glandular epithelial cells of human endometruim,and their protein expression level were higher in secretory phase than those in proliferated phase(P<0.05).Conclusions The differential expression of MLL1 in different phase of human normal menstrual cycle and it will up-regulate in secretary phase.All date suggests that MLL1 probably play important role in establishment of endometrium receptivity.Part Ⅱ The study of Histone methylase MLL1 in mouse uterus during embryo peri-implantationObjective To investigate the expression and the role of MLL1 during peri-implantation process of embryos.MethodsCollecting the endometrium samples in early pregnant mice(D1、D4、D5、D6、D8)and virgin mices(D0).The expression level of MLL1 m RNA and MLL1 protein were determined by RT-PCR and Western Blotting,respectively,and the distribution of MLL1 was performed by immunohistochemistry.On the third day of pregnancy,the mices were given an intrauterine injection of the inhibitor of MLL1.The implantation sites were identified by intravenous injection through tail vein of Chicago blue,besides,the number of embryos were counted.Results1)the expression of MLL1 and HOXA10 m RNA in endometrium of pregnant mice were gradually increased as days went,and it reached a peak at pregnant day4(P<0.05)and declined thereafter.2)the expression level of MLL1 protein has same trend as the MLL1 m RNA expression level,the MLL1 protein level presented an upregulated trend and reached a peak on D4(P<0.05)of pregnancy and decreased thereafter.Immunohistochemistry displays that the MLL1 protein was located mainly in luminal epithelium and glandular epithelium on D0.D1 and D4.On D5,MLL1 protein could be detected in stromal cells,and on the D6、D8,the MLL1 protein was exhibited in decidualized cells.30)The number of implanted embryos in the uterus horns by injection inhibitor was markedly decreased compared with those injected nothing,and the expression level of MLL1 m RNA and protein were lowed than that of the blank group and solvent control.Conclusions Histone methyltransferases MLL1 may involve in the development of endometrial receptivity and the process of embryo implantation,besides,it could be that MLL1 play a important role in decidualization of endometrium.