Objectives: To investigate possible effects of estrogen and/or progesterone on the histologic characteristics of female rabbit urinary bladders, we carried out quantitative morphometric analysis of the rabbit bladders.
Methods: Mature female rabbits were treated by ovariectomy with and without successive estrogen and/or progesterone administration. Area densities of the connective tissue (CT) and smooth muscle (SM) cells, the area of single SM cells, and the thickness of the bladder wall were determined by computer-assisted quantitative morphometric analysis.
Results: Six weeks after each treatment, ovariectomy alone resulted in a decrease in CT density of the bladder. Successive estrogen treatment increased the bladder wet weight and SM cell density within the bladder wall. Progesterone treatment reduced CT degradation in ovariectomized rabbits. Sex steroids did not significantly influence the area of each SM cell. There was no significant difference in histologic characteristics between the rabbits treated by estrogen alone and those treated by combination (estrogen and progesterone) therapy.
Conclusions: Ovariectomy and successive hormonal replacement therapy resulted in morphologic changes within the rabbit urinary bladder. Cotreatment with progesterone did not significantly change the morphologic findings produced by estrogen treatment alone.