Pharmacological Progesterone Withdrawal Mouse Menstruation Model And Its Preliminary Study

Uterus is a unique reproductive organ.Endometrial morphology and function undergo characteristic changes every menstrual cycle,including proliferation, differentiation,and shedding,which constitutes a whole menstrual cycle.Abnormal bleeding is a vital clinical problem puzzled by gynaecologist and obstetrician as well as family planning practitioners.Since abnormal bleeding is against regular periodic bleeding,understanding the mechanism underlying periodic bleeding is the key point to reveal the cause of abnormal bleeding and help to solve clinically related problems. Lack of menstruation model is the main limitation of it.Therefore,it is very important to us to induce the menstrual changes in mice for a deep insight into the molecular mechanism of menstruation.1.It is successfully established a menstruation model in mice by pharmacologic withdrawal of progesterone.The difference between our model with the others reported is the way of progesterone withdrawl.In previous models,stopping the supply of progesterone was used to mimic the progesterone withdrawl due to regression of corepus luteum in late stage of the menstrual cycle.In our model, while the progesterone implant was not removed and the serum level of progesterone remained,mifepristone was used to block progesterone action at the receptor level. This resulted in shedding of the decidualized endometrium accompanying with bleeding.The macroscopical and microscopical manifestations were identical to the previous menstruation models.2.To further identify the character of physiology and biochemistry,leukocyte, apoptosis and expression and location of five MMPs and VEGF/R2 which are well known molecules relative to menstruation were studied during mifepristone administration.So,the changes of molecular character in mice model by pharmacologic withdrawal of progesterone were mached to menstruation of human and primates.It was verified that the mice model by pharmacologic withdrawal of progesterone we build has the primary elements of menstruation.It provides a precious platform to understand the molecular mechanism on menstruation.3.Some different characters on menstruation between mice model and primates. As endometrium was decidualized well by injecting oil to uterus horn,the necrosis and shedding was obvious by progesterone withdrawl.The endometrium showed different zone gradients at the different time points,especially the girdle-shaped zone in which some key chemical fators located.The zone was relative to the shedding zone.These characters not only inferred the potential molecular mechanism,but also was convenient for futher exploration.4.As an effort to use the mouse model,the signal pathways after early progesterone withdrawl was explored,A real-time PCR Array-Signal Transduction Pathway Finder was used to analyze gene expression at 0 h,8 h andl6 h after treatment of mifepristone based on the model.The PCR Array profiles expression of 84 key genes represents 18 different signal transduction pathways.We kept eye on a signal pathway of NFκB and tested the function in cell level.We verified NFκB signal pathway plays a critical role in regulating the expression of MMP3 and MMP9.