The Autonomic Nerves Affect The Expression Of Vimentin And Wnt7a In The Rat Uterus During Implantation

Embryo implantation is a complex physiological process. A successful embryo implantation was orchestrated by neurotransmitters, endocrine hormones, cytokines and immune cells. In recent years, researches on embryo implantation regulation mechanism has become a hot topic in reproductive biology. It has been reported that resecting rat autonomic nerves before pregnancy may delay and even block implantation. However, it is not clear about what is the pathway of autonomic nerves regulation of implantation. Our experiment was to explore this question by studying two important proteins responsible for implantation related proteins Vimentin and Wnt7 a. Vimentin is one of the cytoskeleton proteins,participating in migration of endometrial stromal cells, promoting angiogenesis, and playing an important role in embryo implantation. Wnt7 a is an important protein in Wnt signaling pathways. It has been proved to regulate implantation process by classical Wnt signaling pathways(Wnt/β-catenin pathway),regulating implantation process. Our experiment observes rat uterus histological structure changes and express variation of Vimentin and Wnt7 a protein after destroying autonomic nerves, then speculates the approaches of autonomic nerves regulation of implantation.Our experiment used pregnant wistar rats as experimental material to an compares Vimentin and Wnt7 a prorein expression variation in rat uterus on 4d, 5d and 6d of normal to that of ratstreated by autonomic nerve damage, parasympathetic nervous block, vagus nerve damage and sham operation group via immunohistochemistry staining method and quantitative real-time Polymerase Chain Reaction. We found:(1) After damaging the autonomic nervous, the number of embryo implantation points decreased, gland cells and vascular endothelial cells became thinner and smaller, luminal epithelium and glandular epithelium appeared pyknosis and vacuole liked variation phenomenon. It indicated that autonomic nervous damage may activate the apoptotic pathway, which leading to malnutrition and poor blood supply, then affecting embryo implantation.(2) In normal pregnancy group,Vimentin positive cells were mainly located in stromal cells, vascular endothelial cells in normal pregnancy rat. Vimentin expression distinguished significantly between implantation sites and nonimplantation sites. At implantation sites, it was expressed in vascular endothelial cells and decidual cells around the blastocyst, while at nonimplantation sites, it expressed abundantly in vascular endothelial cells and a bit of stromal cells. It suggested that Vimentin participated in decidualization progress and embryo implantation. After damaging autonomic nerve, Vimentin immnuoreactive cells in stromal cells reduced obviously, merely expressed in vascular endothelial cells.(3) Wnt7 a mainly distributed in glandular epithelium and luminal epitheliumin normal pregnancy rat, and mainly focused on anti-mesenterium(blastocyst adhesion location) pregnancy 6d. We also detected Wnt7 a expression was closely related to the distance from implantation sites. At implantation sites, Wnt7 a was strongly expressed in luminal epithelium and decidual cells, while at nonimplantation sites it mainly expressed in luminal epithelium and glandular epithelium. It demonstrated that Wnt7 a participated in the process of embryo implantation, and were closely associated to blastocyst adhesion. After damaging autonomic nerve, Wnt7 a declined in luminal epithelium and glandular epitheliumon pregnancy 6d, further proving autonomic nerve potentially participate in Wnt/β-catenin signaling pathways, and affect the process of embryo implantation.In short, our experiment showed that damaging rat autonomic nerve leading to implantation delay and implantation sites number declined. The molecular mechanisms possibly was autonomic nerve damaging reduces the expression of Vimentin and Wnt7 a in implantation window phase, affected the development of endometrium blood vessels and glands and decidual process, then ultimately resulted in embryo implantation delay.