Study On Functional Repair Of Rat Endometrium With UBM Biomaterial

Background Intrauterine adhesion refers to the damage of endometrial basement by any factors,leading to partial or complete occlusion of the uterus.Clinically it can cause amenorrhea,menstrual flow reduction,periodic abdominal pain,infertility,recurrent miscarriage,placenta accrete,etc.The trauma of uterine cavity caused by the curettage during pregnancy is the main cause of intrauterine adhesion,TCRA is the main method for the treatment of intrauterine adhesion.However,the postoperative adhesion rate was as high as 62.5%,and the success rate of pregnancy was only 22.5% ~ 33.3%.At present,there are a variety of methods for preventing re-adhesions after intrauterine adhesions separation,including intrauterine placement of IUDs,balloon stents,sodium hyaluronate,amniotic membrane,hormone therapy and so on.However,severe uterine adhesion patients have poor regeneration ability due to the severe damage of endometrium basal layer.Thus,even if hysteroscopy can restored the anatomical structure of the uterine cavity and has multiple treatment methods to prevent adhesion recurrence,but as the endometrial regenerative repair obstacles lead to high rates of recurrence of adhesions.Therefore,it has become an urgent problem to seek more effective treatment for endometrial functional regeneration in clinical practice.Regenerative medicine is believed to be the future of intrauterine adhesions patients,stem cell therapy opens the new chapter of regenerative medicine to repair endometrial.However,stem cell used in clinical has many restrictions which hinders its development.Tissue engineering provides a new option for endometrial regeneration.Biomaterial for the regeneration of tissue and organs in the abdominal wall,oral cavity,skin,breast and other fields have achieved good clinical results.However,in the uterine cavity of endometrial regenerative repair is still in its infancy,only a small number of animal experiments reported.The urinary bladder matrix(UBM)is a derived ECM biomaterial with a complete basement membrane.Basement membrane is a specialized ECM structure that separates cells from connective tissue,supporting epithelial cells,endothelial cells,myocytes,and Schwann cells.The integrity of basement membrane is the basis for the body to fully self-functional repair(endometrial / skin / muscle / cornea).And it has a grate advantages of tissue repair.The immunogenicity of UBM close to the natural exemption.It can naturally tolerate infection,and it has the ideal mechanical properties and higher biological activity and tissue regeneration induced ability.In this study,we implanted UBM biomaterials into rat uterus with impaired uterine endometrium to evaluate the effect of UBM biomaterials on the regeneration and repair of injured endometrium,which in order to provide some evidences for the clinical treatment of UBM in intrauterine adhesion.Methods 1.After cutting the uterine horn and injuring the endometrium of the SD rats,the rats in the experimental group were implanted into the uterine horn of the uterine cavity of the rats in the experimental group,and the endometrium of the positive control group was sutured directly to the uterus.The sham-operated group was incised Uterine horn does not damage the endometrium after suture,the negative control group without any treatment.2.The uterine horn specimens of each group were collected two weeks and four weeks after operation.HE staining,massion staining and immunohistochemistry were used to observe the histological changes of endometrium and the changes of Ki67 and microvessels.The intrauterine adhesions related factors In endometrium.3.At 8 weeks after operation,the endometrial receptivity was evaluated by RT-PCR to detect the expression of integrin ?V?3 and LIF in the uterus on the 5th day of gestation.The number of embryos in the uterus of the rat and the position of embryo implantation were evaluated in the third trimester.Results 1.Uterine general appearance: endometrial injury two weeks or four weeks,the rate of uterine effusion in UBM material repair group was significantly lower than the injury control group.2.Endometrial thickness measurement: and the number of endometrial glands counted at 4 weeks after the endometrial lesions: the endometrial thickness and number of endometrial glands in UBM group were all significantly higher than the injury control group,and similar with normal control group,sham group.3.The results of Masson staining showed that a large number of collagen fibers were deposited in the injury group,and scarring was serious.The area of fibrosis in the UBM group was significantly lower than that in the injury control group.4.The results of immunohistochemistry showed that the number of proliferating cells and the number of microvessels in UBM group were significantly higher than those in control group.5.The results of RT-PCR showed that expressions of anti-inflammatory cytokine mRNAs(basic fibroblast growth factor [b FGF])in the UBM group were significantly higher than those in the control group.The mRNA expression of pro-inflammatory cytokines,such as tumor necrosis factor ?(TNF?),was significantly lower in the UBM group than in the injury control group.The mRNA expression levels of TIMP,PDGFBB,TGF-B and COLIA1 were significantly lower in the UBM than in the injury control group.The mRNA expression of RUNX,an anti-fibrosis factor,in UBM repair group was significantly higher than that in injured control group.6.Endometrial receptivity related indicators integrin ?V?3,LIF mRNA expression in the UBM group were significantly higher than the injury control group.7.The results of pregnancy showed that the pregnancy rate in UBM group was close to normal control group and sham operation group,which was significantly higher than that in injury control group.In UBM group the number of embryos were higher than that in injured control group but less than that in normal control group and sham operation group.Conclusion 1.UBM used to repair damaged endometrium can reduce the fibrosis of endometrial tissue,promote the formation of new blood vessels and cell proliferation,reduce profibrotic cytokines,increase the secretion of antifibrotic cytokines,and can inhibit fibrosis to promotes regeneration of the endometrium.2.Repairing the endometrium of Intrauterine adhesions by UBM can improve the expression of LIF and integrin ?V?3,and improve endometrial receptivity and fertility.