Effect of Testosterone on the Phenotypic Modulation of Corpus Cavernosum Smooth Muscle Cells in a Castrated Rat Model

Abstract

To investigate the effect of testosterone (T) on the phenotypic modulation of corpus cavernosum smooth muscle (CCSM) cells in a castrated rat model. Thirty male Sprague-Dawley rats were randomly divided into 3 groups: control, castration, and castration with T supplementation (castration + T). Erectile function, histologic change, and biochemical markers were assessed for phenotypic modulation of CCSM cells in corporal tissue. Moreover, the primary rat CCSM cells were isolated and examined by Western blot analysis. Our data showed that serum T level, mean weight of the body, erectile function, and smooth muscle-to-collagen ratio were significantly decreased in the castration group compared with those in the control and castration + T groups. The expressions of CCSM cells' phenotypic markers, such as α-smooth muscle actin, calponin, and smooth muscle myosin heavy chain 11, were markedly lower, whereas osteopontin protein expression was significantly higher in castrated rats than in control and castrated + T rats. In addition, the immunofluorescence staining of α-smooth muscle actin and calponin markedly decreased in the primary CCSM cells of the castrated rats compared with the intensity of the control and the castration + T rats. CCSM cells undergo phenotype modulation in castrated rats, whereas T reversed the alterations. T may play a key role in the phenotype modulation of CCSM cells.