Bladder outlet obstruction induces a rapid
hypertrophy characterized by increased bladder mass and
collagen deposition. An increase in
collagen is likely to reduce the contractility and compliance of bladder wall. This study was undertaken to investigate the effects of partial
bladder outlet obstruction and its relief on types I and III
collagen, and the relationship between detrusor contractility and
collagen types. A total of 40 female rats was used for experiment and divided into one control, one obstruction, and three recovery groups. The contractility to field stimulation was recorded; total
collagen and
collagen concentration were quantified. The localization of types I and III
collagen and the expression of pro-alpha1(I) and alpha1(III)
collagen mRNA were determined by immunohistochemical staining and Northern blot hybridization, respectively. Contractile response to field stimulation was reduced after obstruction and recovered following relief. The total amount of
collagen increased after obstruction and decreased after relief; however,
collagen concentration decreased after obstruction and increased following relief. Contractility correlated negatively with total
collagen but positively with
collagen concentration. The
protein deposition of types 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 regulated after obstruction, but down regulated after relief. Negative correlation between contractility and gene expressions of
collagen types was significant. These data suggest that the change in localization and quantity of
collagen types leads to morphologic changes of bladder and can have an impact on the contractility of detrusor. Neurourol. Urodynam. 19:29-42, 2000.