To study the effects of overweight and obesity on the stress urinary incontinence (SUI) models of SD rats that made by full-term pregnancy, birth trauma and ovarian castration and its possible molecular biological mechanisms.

Overweight and obesity models of SD rats were established by feeding high fat food. SUI models of SD rats were made by full-term pregnancy, birth trauma and ovarian castration. Body mass index (BMI) was used to detect the clinical characteristics of rats of overweight and obesity. The sneezing experiment, urodynamic experiment and HE staining pathology were used to assess the clinical characteristics of SD rats of SUI. Flow cytometry (FCM) was used to detect the apoptosis rate of urethral sphincte. The activity of SOD and CAT, the content of GSH and MDA of SUI rats’ urethral sphincter were measured by ELISA. qRT-PCR and western blotting were used to detect the mRNA and protein expression of urethral sphincter, such as bcl-2, bax, caspase-3.

Overweight and obesity of SD rats on were successfully established by high-fat feeding, and the SUI models of SD rats were perfectly made by full-term pregnancy, birth trauma and ovarian castration. The apoptosis rate of urethral sphincter was positively correlated with the BMI, and there was statistically significant difference compared with the control group (P<0.05), SOD activity, CAT activity and GSH content and BMI were positively correlated to BMI, MDA and negatively correlated to MBI, and there were statistically significant difference compared with the control group (P<0.05), accompanied with the bcl-2 mRNA and protein down-regulation, bax and caspase-3 mRNA and protein up-regulation, and there was statistically significant difference compared with the control group (P<0.05).

Overweight and obesity could cause the development of SUI models of SD rats, the molecular mechanism may be related to overweight and obesity induce oxidative stress of urethral sphincter and damage cell membrane and induce apoptosis.