Effects of castration on the expression of aquaporins and apoptosis in the ventral prostate

BackgroundAquaporins (AQPs) are transmembrane proteins that play a major role in the regulation of membrane water permeability. The purpose of this study was to determine the expression and localization of AQPs in the ventral prostate (VP) and to predict a possible role for AQPs in apoptotic rat VP, as there has been little research on the expression of AQPs in rat prostate.MethodsMale Sprague–Dawley rats were divided into two groups: a control group and a castration group. The expression and cellular localization of AQPs 1–9 in the VP were determined using immunochemistry and Western blot analysis, respectively. Apoptosis of the VP was determined using Western blot analysis of Bax and Bcl-2 proteins.ResultsAmong the AQPs, AQP1 and 9 were expressed in rat VP. AQP9 expression was localized on the epithelial cell membranes in the intermediate region, which has a secretary function. The expression of AQP1 was not changed after castration; however, the expression of AQP9 was significantly decreased. Apoptosis of the epithelium developed on day 1 after castration and reached a maximum on day 3. At that time, the expression of AQP9 was highly preserved.ConclusionsIn rat VP, only AQP9 was expressed on the epithelial cell membrane in the intermediate region, which has a secretary function, implying that AQP9 may play a role in secretory processes. The apoptotic process and AQP9 expression was correlated, so further study of the role of AQPs in castration-induced apoptotic and transition processes will be required.