[Effects of 7-difluoromethy-5, 4'-dimethoxygenistein on 
stress urinary incontinence model in rats and its mechanisms].

To investigate the effects of 7-difluoromethy-5, 4'-dimethoxygenistein (DFMG) on stress urinary incontinence (SUI) model in Sprague Dawley (SD) rats and its possible mechanisms.

Methods

SD rat model of SUI was established through simulating pregnancy, birth trauma and ovarian castration. The rats were divided into a normal control group, a SUI group, and a DFMG group at 10 or 20 mg/kg. They were treated with 10 mg/kg normal saline (NS), 10 mg/kg NS, 10 mg/kg DFMG and 20 mg/kg DFMG, respectively, via gastric gavage every other day. Maximal bladder capacity (MBC), leak point pressure (LPP), abdominal leak point pressure (ALPP), hematoxylin-eosin (HE) staining, and Masson staining were performed to detect the index for the model. MiR-26b and its down-stream gene phosphatase and tensin homolog deleted on chromosome 10 (PENT) mRNA in urethral sphincter muscles cells (USMCs) were analyzed by RT-PCR. The protein levels of PENT, phosphatidylinositol 3-kinase (PI3K), protein kinaseB (AKT), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), cytochrome C(Cyt-c) and caspase-3 were examined by Western blot. The apoptotic rate of USMCs was determined by flow cytometry (FCM), and the proliferative rate of USMCs was examined by MTT assay.

Results

The SD rat model of SUI was successfully established. HE staining and Masson staining showed that the pathological features of urethral sphincter were improved in the DFMG-treated groups compared with the SUI group. The urine dynamics indexes of model rats, such as MBC, LPP and ALPP, were improved (all P﹤0.05). The results of RT-PCR showed that the miR-26b mRNA was up-regulated (P﹤0.05) and PENT mRNA was down-regulated (P﹤0.05) in the DFMG-treated groups compared with the SUI group. Simultaneously, compared with the SUI group, the protein levels of PENT, Bax, Cyt-c and caspase-3 were down-regulated (all P﹤0.05) and the protein levels of PI3K, AKT and Bcl-2 protein were up-regulated (all P﹤0.05), accompanied by the decreased apoptotic rate of USMCs (P﹤0.05) and the increased proliferative rate of USMCs (P﹤0.05) in the DFMG-treated groups.

Conclusion

The DFMG can significantly improve the symptoms of urinary dynamics, which might be related to the up-regulation of miR-26b expression and the regulation of PI3/AKT-Bcl-2/ Bax signaling pathways.