Structural changes in the bladder walls of pregnant and hormone‐treated rats: correlation with bladder dynamics

OBJECTIVE To evaluate the effects of oestrogen, progesterone and pregnancy on bladder dynamics, and assess the associated histological and structural changes in the bladder wall in a rat model. MATERIALS AND METHODS Adult female Sprague‐Dawley rats were divided into groups and treated as follows: nonpregnant controls (NC); pregnant (PG); oophorectomized and treated with oestrogen (ES); oophorectomized and treated with progesterone (PR); and oophorectomized controls (OO). Simultaneous and continuous renal pelvic and bladder pressures were recorded during bladder filling and emptying. Connective tissue and smooth muscle were analysed morphometrically and quantitatively, and immunohistochemistry used to evaluate the distribution and expression of collagen types I, III and IV. RESULTS PG rats had significantly greater bladder compliance than NC, OO and PR rats (P