Expression And Regulation Of E-cadherin And DP In Canine Uterus

The implantation of the blastocyst into the maternal uterus is a crucial step during pregnancy establishment and maintenance in mammalian reproduction. Successful implantation depends upon the interaction between blastocyst and uterus,it needs not only adherency blastocyst,but also needs "accepted" conditions of endometruim. The bitch is a kind of multiple pregnancy animal with the estrus cycle long for 4-8 month and the reproductive obstacles exists in bitches, which cause the lower rate of birth. The aim of this study was to investigate the expression of E-cadherin and DP in canine uterus during early pregnancy and oestrous cycle using in situ hybridization, studying regulation rule of steroid using ovariectomy model, investigating the effect of E-cadherin and DP during canine reproductive process.E-cadherin plays not only important role in endometria receptivity and embryo adhesion,but also involves in embryo development. The E-cadherin on the surface of embryo can be the ligand/receptor of the similar molecular on the endometrium cells, which makes the embryo adhere to the endometrium. At the time blastocyst implantation,the endometrium embryo can adjust the implantation process. The implantation window in endometriun is controlled by ovarian hormones and embryo, those develop at the same time advance the development of implantation. Our result showed that E-cadherin mRNA was mainly localized in glandular epithelium and expressed weakly in luminal epithelium in canine uterus. There was a low level expression of E-cadherin in the early pregnancy. At the time the embryo implantation, E-cadherin was expressed highly in the glandular epithelium. Then the expression of E-cadherin gradually declined and reached a low level after the embryo implantation. During the estrous cycle, there was little detectable E-cadherin in canine uterus at anestrous stage and diestrus stage. In the ovariectomized canine uterus progesterone slightly induced the expression of E-cadherin. Estrogen cannot induce the expression in the ovariectomized canine uterus. These results suggest that E-cadherin expression is closely related to canine implantation.Prostaglandin D₂ is a member of the prostaglandin family, which widely distributes in all mammals and plays many physiological functions. PGD₂ can be found on the surface of cells with specific receptors, which mediates through the signal transmission mechanism emerge the biological function. Prostaglandin D receptor has been cloned and named as DP. DP is a kind of transmembrane protein, mainly exists in mastocyte, dendritic cells and the tracheal smooth muscle cells. DP plays main role during embryo implantation, adjusting the xpression and regulation of important molecular affecting embryo implantation. DP was mainly localized in glandular epithelium in canine uterus during the early prognancy. There was a low expression of DP in the glandular epithelium during the early pregnancy. When embryo implanted, DP was highly expressed in the glandular epithelium immediately surrounding the embryo. Subsequenctly,expression of DP gradually declined. During the estrous cycle, there was little detectable DP in canine uterus. Neither estrogen nor progesterone significantly induced the expression of DP in the ovariectomized canine uterus. These results suggest that DP expression is closely related to canine implantation.The research results will provide important scientific basis to understand the function of E-cadherin and DP in embryonic development, embryo implantation process and mprovement reproduction and confirm the mechanism of delayed implantation.