Expression of aquaporin water channels in the vagina in premenopausal women

Abstract

Introduction. Aquaporins (AQPs) are membrane proteins that facilitate water movement across biological membranes. This study builds on a previous report on the distinct localization of AQPs in the rat vagina. Aim. The purposes of this study were to investigate the localization and expression of the AQPs in the vaginal tissue of premenopausal women. Methods. Anterior vaginal tissue was collected during transvaginal uterine myomectomy or hysterectomy from 10 premenopausal women (mean age, 40years) for Western blot and immunohistochemistry. Main Outcome Measures. The expression and cellular localization of AQP1-9 were determined in the human vagina by Western blot and immunohistochemistry. Results. Immunolabeling showed that AQP1 was mainly expressed in the capillaries and venules of the vagina, AQP2 was expressed in the cytoplasm of the epithelium, AQP3 was mainly associated with the plasma membrane of the vaginal epithelium, and both AQP5 and AQP6 were expressed in the cytoplasm throughout all vaginal epithelium. Western blot analysis revealed bands at 28kDa for AQP1, 2, 3, 5, and 6 proteins. However, AQP4, 7, 8, and 9 were not detected. Conclusions. The distinct localization of AQPs in the human vagina suggests that AQP1, 2, 3, 5, and 6 may play an important role in vaginal lubrication in women. © 2011 International Society for Sexual Medicine.