The Spatio-temporal Expression Of Leptin During Embryo Peri-Implantation Process In Mice

Embryo implantation, which is crucial to establish successful pregnancy, is a complex physiological process during which fertilized eggs undergo development until the hatched blastocyst stage and subsequently invade endometrium. Implantation is accomplished through three processes in vivo, i. e. apposition, attachment and invasion. A key process of embryo implantation is invasion of cytotrophoblast cells into endometrium, and establishment of placenta together with it's maternal elements. An appropriate and specific molecular dialogues must also take place between cytotrophoblast cells of villous trophoblast and the luminal epithelial and stromal cells of maternal decidua. The human embryo implants about 7—11 days after LH peak,and in mouse, the implantation window lasts for about 24h at day 4-5 of pregnancy.However,embryo implantation is controlled by a variety of hormones, growth factors, adhesion factors and so on. In previous study, a natural knockout model of leptin is the ob/ob mouse, which point mutation of ob gene occurred resulting in the total absence of functional leptin. ob/ob mice are obese and infertile. Fertility could be restored by treatment with exogenous leptin. However, pregnancy will be interrupted if leptin treatment was not continued before 4 day of pregnancy. So, physical leptin concentration is essential for healthy reproduction while abnormal leptin concentration will be adverse to reproductive function even lead to infertility.To better understand the effect of leptin during peri-implantation process, we investigated expression of leptin in mouse uterus and embryos during peri-implantation process by RT-PCR, immunohistochemistry and immunofluoresence.Experiment one Objective: To investigate expression of leptin in pregnant mouse uterus. Methods: Sexual matured NIH female mice were superovulated by an intra-peritoneal injection of pregnant mare serum gonadotrophin (PMSG) followed by a single injection of human chorionic gonadotrophin (hCG) 48h later, and then were mated with fertile males of the same strain. The uteri tissue was collected from the pregnant mice of through day 1 to day 6 killed by cervical dislocation. The uterus horns were rinsed with DMEM/F12 medium adequately, then subject to the following procedures:...