Rabbit As A Model For Deep Implantation And Placentation—the Similarity With Humen

Implantation is a unique reproductive physiology phenomenon in mammalian. In the implantation process, trophoblasts of embryo perform recognition, adhesion and invasion behavior, while endometrium perform decidual reaction. The trophoblastic cells contact fully with the mother, thus maternal nutritional substances and fetal’s information could exchange effectively, implantation is a fine, complex progress which is between the embryo and the mother.The depth of implantation often determines the fortune of the pregnancy. If the placenta’s implantation is too strong, the mother’s womb would be damaged easily. If the placenta implantation is too weak, the fetal’s perfusion would be defective always. For example, the defective decidualization may cause the placenta accrete disease that the placenta invase into the myometrium defectively; weak invasion of trophoblasts’into endometrium often result in the preeclampsia disease in which uterine spiral arteries’ recast is defective. And, decidualization and trophoblast invasion are two important aspects affecting the placental implantation.Molecular mechanisms of trophoblast invasion and decidualization are of great significance in the basic research and clinical guidance. In recent years, many researchers pay a lot of attention on the decidualization and trophoblast invasion. Not only because decidualization could be induced by hormone without mechanical stimulus, but also the similarity of the reproductive system on genomics and placental perfusion with humen, the rabbits are suitable animal models for the mechanism study of pregnancy. Therefore, we try to induce decidualization with estrogen and progesterone on New Zealand rabbits, and to bserve the effects of estradiol on the progression of decidualization.Objective:To observe the decidualization in rabbits inducted by estradiol and progesterone and the influence of estradiol on decidual cells’s invasion behavior Methods:Induce the decidual change of the endometrium with progesterone and estradiol by subcutaneous implanting on New Zealand rabbits. Release rate of progesterone is1600ug/day, release rate of estradiol is60ug/day and20ug/day respectively. Use the method of HE staining and AP staining to observe the decidual change. We divided the rabbits treated with hormone into two groups according to the quantity of eatradiol in the tube. Results:The endometrium of experimental groups were successfully decidualized, decidualized cells were mainly perivascular cells and the cells below the luminal epithelium. Deponding on the appearance of the uterus, the myometrium of the high-dose estradiol group was significantly dam-aged. In the high-dose estradiol group, the number of AP signals appeared in the myometrium was significantly higher than the number of low-dose estradiol group, while there was no AP signals in myometrium of the control group. Conclusions:Similarly to humen, decidualization of rabbits’endometrium start from the perivascular, and, estradiol could promote the decidualized stromal cells deep into the myometrium.Objective:Our aim is to observe perivascular chemokines IL-8, MCP-1and COX-2’s expression during early pregnancy of rabbits. Methed:Quantitative real-time PCR method to observe IL-8mRNA, MCP-1mRNA and COX-2mRNA expression in early pregnancy and non-pregnancy uterus of rabbits, immunohistochemistry method to observe localization of IL-8, MCP-1and COX-2in the early pregnancy and non-pregnancy tabbits. Results:Compared with non-pregnant uterus, during early pregnancy, IL-8levels was significantly higher (P<0.05), MCP-1levels was significantly higher (P<0.01), the expression of COX-2is significantly increased (P <0.01). The levels of COX-2increased nearly four times. Results of immunohistochemical staining displayed that in nonpregnant uterus, localization of IL-8MCP-1and COX-2were mainly in vascular endothelial cells, in the luminal epithelium and glandular epithelium cells COX-2were also expressed. During early pregnancy, localization of IL-8, MCP-1and COX-2were mainly in vascular endothelial cells, decidualized perivascular cells and non-decidualized sromal cells. Conclusion:IL-8, MCP-1and expression of COX-2in rabbit uterus and human endometrial tissues are very similar.Objective:Our aim is to investigate the depth and pattern of trophoblastic cells invasion in pregnant rabbit uterus. Methods:The placenta of pregnant New Zealand rabbit from day6to day15was obtained. HE staining and CK7immunohistochemistry was used to observe the invasion of trophoblastic cells, and HE, AP and PAS staining were also applied to observe the perivascular decidual changes. Results:On day7.5, implantation points was observed; on day9, perivascular cells began to show the decidual changes, moreover, trophoblastic cells began to invade into endometrial stroma; on day10.5, perivascular decidual cells vacuolated, labyrinthine appeared, and syntrophoblast cells was increased; on day12, trophoblastic cells in the labyrinthine and subplacenta were dramatically increased, and the vacuolating of the decidual cells reached its maximum and artery sinus appeared in subplacenta area; on days13-14, artery sinus were enlarged; on day15, the placenta developed well, and trophoblastic cells nearly invaded into the whole subplacenta area. Conclusion:During the pregnancy of rabbit, trophoblastic cells invade into the decidual area and the artery of myometrium in different ways including interstitial infiltration, decidual cells infiltration and retrograde migration in the uterine spiral artery.