Animal Model Study On The Function And Structure Of Pelvic Floor Influenced By Simulating Birth Trauma And Menopause

Objectives:1. To investigate the establishing female rats of SUI can obtained by simulating humanpregnancy, birth trauma, dense birth and menopause, and according to the index of urinarydynamics and the positive rate of sneeze tests to test the feasibility of model. This studyprovided the proof to treat stress urinary incontinence with injection.2. To observe the alteration of histology and morphology in model rat of urethra and surroundingtissues, pubocoecygeus. Change of these tissues showed that chronic injury leading to thechange of function and structure of pelvic framework was one of the cause of SUI.Materials and Methods:1. The establishment of SUI models: Anesthetized immediately after delivery, female rats weretaken 14F catheter inserting 2-3cm in the vagina, aerocyst was injected 5ml PS, and fixedthe catheter to the vaginal orifice with silk suture, fixation the state 4h; do the operation againafter 2 weeks; and do bilateral ovariectomy after 2 weeks again. Rats were injectedantibiotics 7 days continuously. At last, we gained the SUI model after ordinary breeding 2months.2. To use the instrument BL-410 biology and function experiment system to check the model.The indexes of urinary dynamics were the maximum bladder capacity, leak point pressureand the positive rate of sneezing test.3. The urethra and the surrounding tissues, pubococcygeus muscle samples were obtained from45 rats (25 rats of model group, 20 rats of control group), the biopsies were fixed, embeddedand sectioned. The HE, Masson's trichrome stains revealed the morphology among urethraand surrounding tissue, the immunohistochemistry assay was used to determine the contentsof collagen typeⅠ. All the samples were analysed under microscope by the same person for the histological characteristic.Results:1. The SUI rats model: models were established by simulating human pregnancy, birth trauma,dense birth, menopause. It showed it was a successful and stable model. Compare with thecontrol, Urodynamics measurement showed that the maximum bladder capacity of modelrats were less (1.54±0.25 vs. 2.50±0.33, p＜0.05, ml), leak point pressure were less (10.86±0.91 vs. 28.39±1.11, p＜0.05, mmHg) than the control group, the positive rate of sneezingtests were (64%/0, P＜0.05) more than the control group. The achievement ratio of model is64%.2. The biopsies of HE and Masson's trichrome staining in slides showed the sphincter ofurethra, collagen fibers were sparse distribution, fibre density of pubococcygeus muscle wasdiminished, any had degeneration, compared with the control group.3. The immunohistochemistry staining showed Collagen typeⅠin the tunica muscularis andblank of pubococcygeus muscles, The strain of collagen positive area and positive unit weresignificant lower, the grey was higher, compared with those of control group(P＜0.05).Conclusion:1. At the same position, urodynamics measurement showed maximum bladder capacity, leakpoint pressure significantly decreased compared with that in the control, the sneeze test ofmodel rats were increased with that in the control. These reveals the rationality of the idea,the feasibility and stability of establishment.2. This experiment reveals pregnancy, birth trauma, dense birth and menopause are the causesof the SUI.3. Compared with those of control group, the indexes of urinary dynamics and the positive rateof sneeze tests, The sphincter of urethra and collagen fibers weren't integrality, Themorphology in pubococcygeus were changed, collagen typeⅠwere diminished, these shows thechange of function and structure of pelvic floor is one of the cause of SUI.