Abstract:

Objective To discuss the effect of Cav 3.2 gene in the treatment of stress urinary incontinence （SUI） of the mice by pelvic floor electrical stimulation （PES）， and to clarify its related mechanism. Methods Thirty C57BL/6 mice were randomly divided into control group ［without vaginal dilation （VD） modeling］， VD group （VD modeling）， and VD+PES group （VD modeling combined with PES） according to the intervention measures， and there were 10 mice in each group. The mice were divided into WT-VD group （wild-type VD modeling）， WT-VD+PES group （wild-type VD modeling combined with PES）， KO-VD group （Cav 3.2 knockout type VD modeling）， and KO-VD+PES group （Cav 3.2 knockout type VD modeling combined with PES） according to the genotype and intervention mesures. Masson staining was used to observe the deposition and expression levels of collagen type Ⅰ（Col Ⅰ） and collagen type Ⅲ （Col Ⅲ） collagen fibers in urethral and anterior vaginal wall tissue of the mice in various groups. The maximum bladder capacity（MBC） and leakage point pressure （LPP） of the mice in various groups were detected， and the expression levels of integrins β1， calpain 2， Col Ⅰ， and Col Ⅲ proteins in urethral and anterior vaginal wall tissue of the mice in various groups were detected by Western blotting method. Results Compared with VD group， the expression levels of Col Ⅰ and Col Ⅲ collagen fibers in urethral and anterior vaginal wall tissue of the mice in VD+PES group mice were significantly increased （P<0.01）； compared with WT-VD group， the expression levels of Col Ⅰ and Col Ⅲ collagen fibers in urethral and anterior vaginal wall tissue of the mice in WT-VD+PES group were significantly increased （P<0.01）； compared with WT-VD+PES group， the expression levels of Col I and Col Ⅲ collagen fibers in urethral and anterior vaginal wall tissue of the mice in KO-VD and KO-VD+PES groups were significantly decreased （P<0.01）. Compared with control group， the MBC and LPP of the mice in VD group were decreased （P<0.05）； compared with VD group， the MBC and LPP of the mice in VD+PES group were increased （P<0.05）. The Western blotting results showed that compared with VD group， the expression levels of Col Ⅰ and Col Ⅲ proteins in urethral and anterior vaginal wall tissue of the mice in VD+PES group were significantly increased （P<0.01）； compared with WT-VD group， the expression levels of Col Ⅰ and Col Ⅲ proteins in urethral and anterior vaginal wall tissue of the mice in WT-VD+PES group were increased （P<0.01）； compared with WT-VD+PES group， the expression levels of Col Ⅰ and Col Ⅲ proteins in urethral and anterior vaginal wall tissues of the mice in KO-VD and KO-VD+PES groups were significantly decreased（P<0.01）. Compared with WT-VD group， the expression levels of integrin β1 and calpain 2 proteins in urethral and anterior vaginal wall tissue of the mice in WT-VD+PES group were increased significantly （P<0.01）. Conclusion PES can improve the urodynamic function of the mice and promote the generation of pelvic floor collagen and promote the repairment of pelvic floor through the Cav 3.2 gene and its downstream integrin β 1 and calpain 2.

Key words: Pelvic electrical stimulation, Cav3.2 gene, Integrin β1, Calpain 2, Mice, C57BL/6, Stress urinary incontinence