Establishment Of Animal Model Of Stress Urinary Incontinence In SD Rats And Detection Of NOS, COX-2, P38

1. Objective:1.1 To establish the stable and reliable animal model for stress urinary incontinence (SUI) in SD rats.1.2 To investigate the expression of nitric oxide synthase (iNOS, nNOS, eNOS), cyclooxygenase 2(COX-2) and P38MAPK in vaginase, urethra and levator ani muscle between SUI rats and normal rats.1.3 To explore the probable mechanism of genisis and progression in SUI animal model.2. Methods:2.1 Sixty female SD rats were divided into 3 groups. Group A (14 rats) was the group of normal childbirth. Group B (22 rats) was the group of normal childbirth+ colpectasis. Group C(24 rats) was the group of normal childbirth+colpectasis+ ovariectomy.2.2 Cystometry and modified leak point pressure measurement was used to test the effect for 3 groups SD rats.2.3 Sixty female SD rats of Group A, Group B and Group C were respectively randomized separated into 2 groups and the SD rats of each group were equal:the SD rats in Group A1,Group B1 and Group C1 were injected physiological saline in the abdominal cavity. the SD rats Group A2, Group B2 and Group C2 were injected in SMT the abdominal cavity.2.4 After the experiment, vagina, urethra and levator ani muscle of subgroup SD rats were respectively extracted. The expression of iNOS, nNOS, eNOS, COX-2, P38 in vagina, urethra and levator ani muscle of subgroup SD rats was determined by immunohistochemical analysis. We studied the expression difference of five factors between SUI group and control group rats.3. Results:3.1 The abdominal leak point pressure (ALPP) in group A, B and C was (64.85+ 2.44)cmH2O, (45.20 ± 2.78)cmH2O, (44.75 ± 2.33)cmH2O. There was statistical difference of ALPP between group A and group B(P=0.001), group A and group C (P=0.001), not between group B and group C(P=0.578). MBC of three groups were (2.82 ± 0.40)ml, (2.77±0.49)ml, (2.78 ± 0.39)ml respectively. There was no significant difference of MBC between group A and group B, group A and groupC, group B and group C respectively(P=0.943). All of the SD rats of Group A were negative. The positive rates of SD rats of Group B was 12/20(60%).and the positive rates of SD rats of Group C was 18/20(90%).3.2 iNOS expressed mainly in the cell nucleus of mucosal epithellal cells of urethra and vagina, and cytoplasm of levator ani muscle tissue cells for three groups SD rats. There was statistical significant difference of integral of degree dyeing of iNOS between Group A, Group B and Group C(P<0.05); the integral of degree dyeing of iNOS was falling in different degrees after injecting SMT, There was statistical significant difference of integral of degree dyeing of iNOS between before and after injecting SMT(P<0.05).3.3 nNOS expressed mainly in cytoplasm of mucosal epithellal cells of vagina and the cell nucleus and cytoplasm of levator ani muscle tissue cells for three groups SD rats. But there was no significant expression in mucosal epithellal cells of urethra, in the vagina and levator ani muscle tissue, There was statistical significant difference of integral of degree dyeing of nNOS between Group A, Group B and Group C(P<0.05); the integral of degree dyeing of nNOS no obvious change after injecting SMT, There was no statistical significant difference of integral of degree dyeing of nNOS between before and after injecting SMT(P>0.05).3.4 eNOS expressed mainly in cytoplasm of levator ani muscle tissue cells for three groups SD rats, But there was no significant expression in mucosal epithellal cells of urethra and vaginase. in the levator ani muscle tissue, There was statistical significant difference of integral of degree dyeing of eNOS between Group A, Group B and Group C(P<0.05); the integral of degree dyeing of eNOS no obvious change after injecting SMT, There was no statistical significant difference of integral of degree dyeing of eNOS between before and after injecting SMT(P>0.05).3.5 COX-2 expressed mainly in cytoplasm of mucosal epithellal cells of vaginase, and cytoplasm of levator ani muscle tissue cells for three groups SD rats. But there was no significant expression in mucosal epithellal cells of urethra, in the vaginase and levator ani muscle tissue, There was statistical significant difference of integral of degree dyeing of COX-2 between Group A, Group B and Group C(P<0.05); the integral of degree dyeing of COX-2 was falling in different degrees after injecting SMT, There was statistical significant difference of integral of degree dyeing of COX-2 between before and after injecting SMT(P<0.05).3.6 P38 expressed mainly in cytoplasm and the cell nucleus of mucosal epithelial cells of urethra and vaginase, and cytoplasm and the cell nucleus of levator ani muscle tissue cells for three groups SD rats. There was no statistical significant difference of integral of degree dyeing of P38 between Group A, Group B and Group C(P>0.05); the integral of degree dyeing of P38 no obvious change after injecting SMT, There was no statistical significant difference of integral of degree dyeing of P38 between before and after injecting SMT(P>0.05).4. Conclusions:4.1 The animal model of stress urinary incontienece can be obtained successfully through imitating birth trauma and/or ovariectomy.4.2 expression changes of iNOS in urethra, vaginase and levator ani muscle was significantly higher than the normal group. And after using of SMT, expression changes of iNOS in urethra, vaginase and levator ani muscle was significantly lower than normal group. It showed that iNOS may play an important role in the incidence of SUI and SMT can inhibit the expression of iNOS.4.3 there was no significant expression for nNOS in urethra of Group A, Group B and Group C. expression changes of nNOS in vaginase and levator ani muscle was significantly higher than the normal group. And after using of SMT, there is no expression changes in vaginase and levator ani muscle for nNOS. It showed that nNOS may play an important role in the incidence of SUI and SMT can not inhibit the expression of nNOS.4.4 there was no significant expression for eNOS in urethra and vaginase of Group A, Group B and Group C. expression changes of eNOS in levator ani muscle was significantly higher than the normal group. And after using of SMT, there is no expression changes in levator ani muscle for eNOS. It showed that eNOS may play an important role in the incidence of SUI and SMT can not inhibit the expression of eNOS.4.5 there was no significant expression for COX-2 in urethra of Group A, Group B and Group C. expression changes of COX-2 in vaginase and levator ani muscle was significantly higher than the normal group. And after using of SMT, expression changes of COX-2 in vaginase and levator ani muscle was significantly lower than normal group. It showed that COX-2 may play an important role in the incidence of SUI and SMT can inhibit the expression of COX-2.4.6 there was no significant expression for P38 in urethra, vaginase and levator ani muscle of Group A, Group B and Group C. And after using of SMT, there is no expression changes in urethra, vaginase and levator ani muscle for P38. It showed that P38 has no influence in the incidence of SUI and SMT can not inhibit the expression of P38.4.7 From what about discussed above all, NOS and COX-2 play the important role in the incidence of SUI. But P38 has no influence in the incidence of SUI.