The effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder functions and histology in surgically menopause and chronic cystitis induced rats

Abstract

We investigated the effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder function and histological changes in surgically menopause and chronic cystitis induced rats. The study included 36 female Sprague-Dawley rats, divided into five groups. After bilateral ovariectomy, chronic cystitis was induced by intravesical instillation of HCl, and then group 1 (n = 8) received nasal estrogen, and group 2 (n = 8) received oral estrogen replacement therapy. Group 3 (n = 7) underwent ovariectomy and chronic cystitis, but no replacement therapy. Group 4 (n = 7) had only ovariectomy. Group 5 (n = 6) was taken as sham group. The rats were sacrificed after 60 days, and cystometric study and histological findings were compared among the groups. The mean maximal bladder capacity and compliance revealed significant decreases in group 3 and 4 compared with group 5, and significant increases in group 1 and 2 compared with group 3. Histological findings showed significant increases in the mast cells and leukocyte infiltration of group 3 and 4 compared with group 5, and significant decreases in the mast cells and leukocyte infiltration of group 1 and 2 compared with group 3. This experimental menopause and chronic cystitis model showed that bladder function and histology might deteriorate much more with chronic cystitis in postmenopausal period. This is the first study in the literature to report that chronic inflammatory bladder occurring after menopause can be improved by estrogen replacement therapy.