Effects of partial bladder outlet obstruction and its relief on types I and III collagen and detrusor contractility in the rat

Bladder outlet obstruction induces a rapid hypertrophy characterized by inc reased bladder mass and collagen deposition. An increase in collagen is lik ely to reduce the contractility and compliance of bladder wall. This study was undertaken to investigate the effects of partial bladder outlet obstruc tion and its relief on types I and III collagen, and the relationship betwe en detrusor contractility and collagen types. A total of 40 female rats was used for experiment and divided into one control, one obstruction, and thr ee recovery groups. The contractility to field stimulation was recorded; to tal collagen and collagen concentration were quantified. The localization o f types I and III collagen and the expression of pro-alpha 1(i) and alpha 1 (III) collagen mRNA were determined by immunohistochemical staining and Nor thern blot hybridization, respectively. Contractile response to field stimu lation was reduced after obstruction and recovered following relief. The to tal amount of collagen increased after obstruction and decreased after reli ef; however, collagen concentration decreased after obstruction and increas ed following relief. Contractility correlated negatively with total collage n but positively with collagen concentration. The protein deposition of typ es I and III collagen was localized in lamina propria and muscle bundles in all groups. The expression of types I and III collagen gene was up regulat ed after obstruction, bur down regulated after relief. Negative correlation between contractility and gene expressions of collagen types was significa nt. These data suggest that the change in localization and quantity of coll agen types leads to morphologic changes of bladder and can have an impact o n the contractility of detrusor. (C) 2000 Wiley-Liss, Inc.