Myocardin restores erectile function in diabetic rats: phenotypic modulation of corpus cavernosum smooth muscle cells

Abstract

This study aimed to investigate whether gene transfer of myocardin to the penis of diabetic rats can modulate corpus cavernosum smooth muscle (CCSM) cells phenotype and restore erectile function. Five normal control rats, and 22 diabetic rats were randomly divided into four groups: rats transfected with adCMV-myocardin (N=6), treated with empty vector (N=6), injected with medium (N=5), and sham-operated rats (N=5). The erectile response was measured 7days after transfection. The percent of smooth muscle and the expressions of SMα-actin, smooth muscle myosin heavy chain (SMMHC), calponin were evaluated. The increases in intracorporal pressure(ICP)/mean arterial pressure and total ICP in response to nerve stimulation in the adCMV-myocardin treated rats were significantly greater than those in the empty vector (P<0.001 and P<0.001), medium only (P<0.001 and P<0.001), and sham-operated rats (P<0.001 and P<0.001). The suppressed expressions of SMα-actin, SMMHC and calponin were completely restored, and the amount of smooth muscle in diabetic rats were not restored after treatment. It is concluded that myocardin ameliorated erectile responses in diabetic rats mainly via promoting phenotypic modulation of CCSM cells from a proliferative to a contractile state.