The Effect Of LMWH On WNT Pathway Affects Endometrial Receptivity

Objective: With the application of assisted reproductive technology in clinical practice,the chances of patients who fail to conceive naturally are greatly improved.However,the rate of embryo implantation is still low,so it is difficult to improve the rate of implantation.Endometrial receptivity plays a key role in embryo implantation,and patients with poor receptivity are prone to repeated implantation failures.The molecular mechanism of maternal-fetal interface is very complex and involves many factors.WNTs is an important regulator of mouse uterine morphogenesis and blastocyst implantation,and beta-catenin is a downstream effector of WNT pathway,and its imbalance will lead to defects in gland formation,decidualization and fertility.In the son of man palace,WNT7 A is present in the endometrial glandular epithelium during both the proliferative and secretory phases of the menstrual cycle and is important for blastocyst implantation and female fertility maintenance.In vitro studies have found that low molecular weight heparin(LMWH)can promote the differentiation and invasion of trophoblastic cells outside the villi.However,there are few in vivo studies on its effect on embryo implantation and even fewer studies on the WNT signaling pathway.Therefore,this study investigated the effect of LMWH on WNT pathway on endometrial receptivity by detecting the morphological changes of endometrium and related molecular changes during the window period of implantation in mice.Methods: A mouse model of failed blastocyst implantation was constructed with mifepristone,and 84 C57BL/6 female mice were randomly divided into 7 groups,blank control group,model group,low dose LMWH treatment group,medium dose LMWH treatment group,high dose LMWH treatment group,aspirin treatment group,and aspirin+ medium dose LMWH treatment group.The estrus was determined by vaginal smear every day,and mice were killed on the 5th day of gestation.The number of embryos in each group was counted,the endometrial tissues were stained with HE,the expressions of WNT7 A,catenin,PECAM1 and IL6 proteins in tissues were detected by immunohistochemistry and western blot,the expressions of related factors of WNT7 A,catenin,PECAM1 and HOXA10 mrnas were detected by q PCR,and the contents of arginine and glycine were detected by liquid phase tandem mass spectrometry.Results:1.The effect of low molecular weight heparin on the number of embryos: the number of embryos in the model group was 6.00±0.74,and that in the LMWH medium dose group was 8.55±0.63,the difference between the two groups was significant(P<0.01).In the treatment group,the group treated with high dose LMWH had the largest number of embryos(9.17±0.58),which was statistically significant compared with the control group(P<0.05).2.The effect of LMWH on blood vessels and glands in endometrial tissues: the number of small blood vessels in the LMWH low-dose treatment group was 16.58±3.81,which was statistically significant compared with the model group(P<0.05).The number of blood vessels in the LMWH high-dose treatment group was higher than that in the LMWH+ aspirin treatment group(P<0.05).Compared with the blank control group,there was no statistically significant difference in the number of endometrial vessels in the LMWH low-dose and medium-dose treatment groups(P>0.05),while the number of endometrial vessels in the LMWH high-dose treatment group and the LMWH+ aspirin treatment group increased slightly,but the difference was not statistically significant(P>0.05).The number of glands in the aspirin treatment group was 19.38±5.42,significantly higher than that in the model group(P<0.05).3.The effect of low molecular weight heparin on protein expression of endometrial molecules: Immunohistochemical analysis and western blot showed that,compared with the model group,the expression of endometrial factors related to the WNT pathway was significantly increased in the LMWH treatment group(P<0.01).Among them,the expression level of WNT7 A protein was the highest in the LMWH medium-dose treatment group(8.14±0.78),and the expression level of beta-catenin protein was the highest in the LMWH high-dose treatment group(51.63±5.77).The positive expression levels of PECAM1 protein and IL6 protein in LMWH high-dose treatment group were51.43±3.46 and 41.86±3.92,respectively,which were significantly different from the model group(P<0.01).4.Low molecular weight heparin regulated endometrial amino acid content: Compared with the model group,the arginine and glycine contents in the LMWH treatment group were significantly increased(P<0.01).Compared with the blank control group,the arginine and glycine contents in the LMWH high-dose treatment group increased significantly(P<0.01),which were 162.03±12.73 and 332.82±60.68,respectively.5.Low molecular weight heparin regulates the m RNA expression of endometrial related molecules: compared with the model group,the expression of endometrial factors related to the WNT pathway was significantly increased in the LMWH treatment group(P<0.01),and the m RNA expression levels of related factors WNT7 A and beta-catenin in the LMWH high-dose treatment group were 4.34±0.86 and 2.34±0.29,respectively,with the most significant difference(P<0.01).The expression levels of PECAM1 and HOXA10 in LMWH medium-dose group were 2.01±0.72 and 2.08±0.68,both significantly higher than that in the model group(P<0.01).Conclusion: LMWH affects endometrial receptivity by acting on the WNT pathway,thereby promoting embryo implantation process.