The molecular effects of electrical stimulation on the muscle components of the urethra of female rats after trauma by vaginal distention.

AIMS: To evaluate the expression of genes and proteins related to the urethral muscles of female rats after trauma by vaginal distention (VD) and after electrical stimulation therapy (EST).

METHODS

We compared the urethras of four groups of 20 animals each: control without trauma (C), 7 (recent-trauma) and 30 days (late-trauma) post-VD, and VD-treated with EST. We evaluated the expression of myogenic regulatory factors MYOD1 and myogenin (MYOG); skeletal muscle myosin heavy chain 1, 2, and 3 (MYH1, MYH2, and MYH3); smooth muscle MYH11; and myosin light chain 9 (MYL9). We used real-time quantitative polymerase chain reaction, Western blot analysis, and immunohistochemistry.

RESULTS

MYOD1 and MYOG genes were overexpressed in the recent-trauma group compared with the other groups (P < .05). MYH1 and MYH3 genes were upregulated in the recent-trauma group compared with the control and EST groups (P < .05). The MYH2 gene was overexpressed in the late-trauma group (P < .05), while the MYH2 protein was significantly increased in the EST group compared with control, recent-trauma and late-trauma groups by 5-, 3-, and 2.7-fold change, respectively (P < .05). MYL9 and MYH11 messenger RNA were overexpressed in both trauma groups compared with control and EST groups (P < .05). MYH11 protein was not different among the study groups (P > .05).

CONCLUSIONS

EST enhances the recovery of the damaged urethral tissue of rats mainly by acting on the striated-muscle components. The MYH2 pathway underlies the positive effects of EST in the external urethral sphincter.