Abstract: Objective: To explore the therapeutic effect of mechano growth factor (MGF) on patients with stress urinary incontinence (SUI) through detecting the survival rate of levator ani myoblasts and the expression of Laminin and Dystrophin in female patients with SUI and patients undergoing radical resection of rectal cancer. Methods：Levator ani myoblasts were isolated from female patients with SUI and patients undergoing radical resection of rectal cancer, and identified by actin immunofluorescence assay. The survival rate of levator ani myoblasts was determined by MTT assay using different concentrations of MGF (0 ng/mL, 50 ng/mL, 100 ng/mL, 150 ng/mL) at different time (24 h, 48 h, 72 h). After 72 hours incubation of myoblasts, the contents of these two proteins were determined by reverse transcription polymerase chain reaction (RT-PCR). Results：The effects of different concentrations of MGF on the proliferation of levator ani myoblasts were different (F浓度=65.055, P浓度=0.000). The effects of different action time of MGF on the proliferation of levator ani myoblasts were different (F时间=24.586, P时间=0.000). There was interaction between MGF concentration and MGF action time(F时间×浓度=3.222, P时间×浓度=0.008). When MGF concentration was 150 ng/mL and MGF action time was 72 h, the survival rate of levator ani myoblasts was the highest. Compared with the control group (levator ani myoblasts of patient undergoing radical resection of rectal cancer), the expression of Laminin and Dystrophin in levator ani myoblasts in SUI group (0 ng/mL) was lower (P＜0.05). Compared with the SUI group (0 ng/mL), the expression of Laminin and Dystrophin in levator ani myoblasts in MGF group (150 ng/mL) was higher (P＜0.05). Conclusions：The concentration of MGF and the action time of MGF can interact with each other to promote the proliferation of levator ani myoblasts in SUI patients cultured in vitro. The expression of Laminin and Dystrophin in levator ani myoblasts decreased in patients with SUI. MGF can promote the expression of Laminin and Dystrophin in levator ani myoblasts of SUI patients.

Key words: Urinary incontinence, stress, Myoblasts, skeletal, Laminin, Dystrophin, Mechano growth factor