Expression of TβR-2, Smad3 and Smad7 in the vaginal anterior wall of postpartum rats with stress urinary incontinence.

PURPOSE: The objective of this study is to quantify and evaluate the expression of several important proteins in TGF-β1/Smad pathway in the anterior vaginal wall in postpartum rats with stress urinary incontinence (SUI).

METHODS

Forty 8-week-old Sprague-Dawley (SD) female rats were randomized into three groups: blank group (n = 10), control group (n = 10) and SUI group (n = 20). Rats in blank group were non-pregnant, while rats in the control and SUI groups underwent normal parturition and normal parturition plus immediate postpartum vaginal balloon dilation, respectively. 1 week after dilation, a sneezing experiment and pad test were performed and the anterior vaginal wall was collected. The histological changes of the anterior vaginal wall were assessed by hematoxylin-eosin (HE) staining, and the expression of TβR-2, Smad3 and Smad7 in the anterior vaginal wall was detected by immunohistochemical staining and Western blotting.

RESULTS

HE staining showed that collagen was more fragmented, sparse and disorganized in the SUI group compared with the control and blank groups. Compared with the blank group, the expression of TβR-2 and Smad7 protein was significantly increased in the vaginal anterior wall in the control and SUI groups (P < 0.05), while their levels in the SUI group were significantly higher than those in the control group (P < 0.05). Expression of Smad3 protein in the anterior vaginal wall of SUI rats was significantly decreased compared with the blank and control groups (P < 0.05).

CONCLUSION

Dysregulation of the TGF-β1/Smad signaling pathway may involve in the pathogenesis of SUI.