Study On The Changes In Expression Of Type I Collagen, MMPS/TIMPs, TNF-α In Pelvic Floor For Pregnant Women In Third Trimester And Their Clinical Meaning

ObjectiveThe study aimed to investigate collagen I content, quantitative mRNA expression ofmatrix metalloproteinases MMP-1,9and their inhibitors, the tissue inhibitors ofmetalloproteinases TIMP-1, TNF-α, in vaginal wall tissue from pregnant women in thirdtrimester compared to continent controls, and explore the relationships between them.Discuss their role in development of postpartum pelvic floor dysfunction.Stated thepathogenetic mechanism of postpartum pelvic floor injury from molecular level,to lay thefoundation for postpartum pelvic floor functional rehabilitation work.MethodsFor this study,25term pregnant women without pregnancy complications(GroupA),25premenopausal women undergoing hysterectomy for benign gynecologic disorderswithout PFD(Group B) and7women have never experienced childbirth(Group C)wereselected. All of them accepted our informed consent before their vaginal wall tissuesamples were extracted.The concentration of type I collagen and TNF-α were detected byimmunohistochemical method(S-P).Messenger RNA levels of MMP-1,MMP-9andTIMP-1were evaluated by relative real-time quantification PCR using an invariableinternal standard. SPSS version13.0was used for statistical analysis. In all cases therejection level for null hypothesis was set at a value less than or equal to0.05(5%).Result The positive effect of type I collagen was expressed in muscle cell interstitial asbrown-yellow or brown-chocolate granular substance, however,MMP-1,MMP-9,TIMP-1,TNF-α were detected in cell membrane and cytoplasm.The mean concentration of type Icollagen was significant reduced (p<0.05) in Group A compared with Group B and GroupC,the decline range is49.5%、40.9%.What’s more,Group B compared with Group C,themean concentration of type I collagen also reduced,but there is no statistical significant(p>0.05),the decline range is15.1%.In Group A, the expression of MMP-9was significantly increased (p<0.05) andTIMP-1was significantly decreased(p<0.05) compared to Group B and Group C. Andthey were with high relativity to the variability of type I collagen,the correlationcoefficients are0.412and0.765respectively(P<0.01).While,the expression of MMP-1was increased compared to Group B and Group C,but there is no statistical significance(p>0.05).In addition to this,compared to Group C,the expression of MMP-1,MMP-9wasincreased and TIMP-1was decreased in Group B,but there were no statistical significant.As for TNF-α, it increased significant in vaginal wall tissue from Group A comparedwith Group B and Group C,and has significant linear correlation with the increasedexpression of MMP-9(r=0.627，P<0.05) and the decrease of TIMP-1(r=-0.494，P<0.05).Conclusion1. Pregnancy,delivery and birth trauma can reduce type I collagen content of pelvicfloor connective tissue, is important causative factor of postpartum pelvic floordysfunction.2. Decline of type I collagen content in pelvic floor connective tissue at latepregnancy may be due to local enhanced expression of MMP-9and decreased expressionof TIMP-1, result in a less tenacity of pelvic floor.3. The changes in the pelvic floor supportive structure during pregnancy andchildbirth resemble an inflammatory process. Direct or indirect regulate and control effectexist between TNF-α and MMP-9.4. Pregnancy and childbirth can damage pelvic floor supportive structure and thepelvic floor connective tissue has self-healing ability at postpartum.But it’s difficult to restore to before delivery status,so as to increase the risk of PFD.Therefore, it would beparticularly important for us to carry on pelvic floor rehabilitation work.