A Preliminary Study On The Effect Of Huc-MSCs Exosomes In Repairing The Mechanical Damage Of The Endometrium And The Disintegration And Bleeding Of The Endometrium Caused By Acute Stress

The uterus is an essential reproductive organ for all fetal females and "the soil" of embryo implantation and development.Higher primates undergo disintegration and shedding of the functional layer of the endometrium under the joint regulation of estrogen and progesterone during the non-gestational state,i.e.,the menstrual cycle,followed by rapid scar free repair.Such renewal of the endometrium prepares the mother for pregnancy.Status of endometrium determines outcome of pregnancy.In this study,the mechanism of mesenchymal stem cell exosomes to repair endometrial injury and the effect of acute stress on endometrial disintegration and exfoliation were investigated.The results of this study will enrich the understanding of endometrial disintegration and repair,and provide diagnostic and treatment strategies for clinicopathology of irregular uterine bleeding and endometrial repair disorder/uterine adhesion,and improve the pregnancy outcome.1.Establishing rat endometrial mechanical injury model and the role of umbilical cord mesenchymal stem cell exosome in repairing damaged endometrium.The main cause of endometrial repair disorder is uterine cavity adhesion,which due to endometrial injury of curettage during abortion.In this paper,a self-made curette was used to penetrate into the uterine horn at the distal end of the rat uterus to simulate curette curette operation on the uterus.Rats with endometrial injury were treated with femoral vein injection of umbilical cord mesenchymal stem cell exosomes as the experimental group and phosphate buffer injection as the control group.At the 1st,3rd,7th,10th and 30th days after injection,samples were collected from the experimental group and the control group,respectively.HE staining,masson staining,Ki67 and VEGF immunohistochemical method and expression profile chip analysis were used to compare the morphology,fibrosis degree and repair related protein expression of uterine tissue.Furthermore,female mice in the experimental group and control group were mated with male mice respectively to observe the pregnancy outcome.The results showed that inflammation and collagenous fiber began to reduce and the stroma cells recoveried.Until 30th day,the injuried endometrial returned to normal basically.Masson staining results showed that the degree of fibrosis on the traumatic surface of the uterus could be reduced after Exosome was given.On day 3-10.the location of Ki67 in the subepithelial stromal cell area of the experimental group was significantly higher than that of the control group.And the expression intensity of VEGF located in the stromal cell area of lumen epithelium was significantly higher than that of the control group,which was the area of injured endometrium repair.The enhanced intensity suggested that Exosomes could promote the repair of endometrial stromal cells,epithelial cells and vascular endothelial cells.Preliminary study of fertility test proved that exosomes were able to repair damaged endometrium and achieve successful pregnancy to a certain extent.2.Establishing menstrual model in mice with pseudopregnancy and the effect of acute stress on endometrial disintegration and bleeding.Progesterone withdrawal is the drive factor of the begining of menstruation and its upstream complex endocrine regulation is not clear.Stress is also a main factor that causes menstruation disorder.We explored the effect of acute stress on the endometrial breakdown and shedding in pseudopregnancy mouse menstrual-like model.ICR female mice were mated with castrated male mice.Recorded time as 0.5 d after vaginal suppository was found.25 μL peanut oil was injected into the either uterus in mice at 15:30 h on day 3.5 to induce endometrial decidualization.On day 5.5,acute stress was applied to observe its’ effect on endometrial breakdown and shedding.The stress related hormone was analyzed by Hormone assay kit.Corticosterone inhibitors and P4 addback were administed to verify the function of corticosterone and P4 in endometrial breakdown and shedding in mice.Immunohistochemistry,Western Blot and qPCR were used to investigate the pathway of endometrial disintegration and bleeding induced by acute stress.The experimental results showed that acute stress could activate the HPA axis,increase serum corticosterone levels,decrease LH and FSH levels,and reduce the activity of HPO axis,leading to the decline of P4 level,and finally lead to endometrial collapse and shedding.Corticosterone may reduce the level of P4 in vivo through the negative regulation of CYP11A1 and StAR.