Cell proliferation and apoptosis in urinary bladder urothelium of rats following ovariectomy and chronic estrogen replacement therapy

AIMS: In this study we followed the effect of menopause and estrogenic replacement therapy on the proliferative and apoptotic activity of the bladder urothelial cells. METHODS: The experimental model of menopause was reproduced using a standard protocol of bilateral ovariectomy in rats, estrogen replacement therapy being achieved by systemic administration of hexestrol diacetate for six weeks. Proliferative and apoptotic activity was monitored by quantifying the urothelium imunoexpression for PCNA antigen as a marker of S phase of the cell cycle and Cleaved Caspase 3 for monitoring apoptotic activity. RESULTS: Following ovariectomy, the main changes were urothelial atrophy associated with intensification of the apoptotic activity at these level. Estrogen therapy managed to improve the urothelium activity by reducing the Apoptotic Index and by increasing urothelial proliferative activity. CONCLUSIONS: The results show the important role of estrogens in maintaining urothelial activities, highlighting their potential use in the treatment of urothelium atrophic and degenerative processes associated with menopause.