Effects of 7-difluoromethy-5, 4'-dimethoxygenistein on stress urinary incontinence model in rats and its mechanisms / 中南大学学报(医学版)

ABSTRACT

Objective:To investigate the effects of 7-difluoromethy-5,4dimethoxygenistein (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.