Partial outlet obstruction in rabbits: duration versus severity.

OBJECTIVES

Oxidative stress is a major etiology of obstructed bladder dysfunction. The major goal of the current study was to correlate the level of oxidative stress with both the severity and duration of obstruction.

METHODS

A total of 32 New Zealand White rabbits were divided into four equal groups. Groups 1-3 received partial bladder outlet obstructions by standard methods and survived for 4, 8 or 12 weeks. Group 4 received sham surgery at the end of each time period, isolated strips were taken for contractility studies and the balance of the bladder was frozen as muscle and mucosa for quantification of nitrotyrosine and carbonyl-oxidized proteins derivatized into dinitrophenyl. For each duration, the eight rabbits were divided into three severity groups: mild, intermediate or severe decompensation.

RESULTS

Contractile responses decreased in proportion to both severity and duration. The level of both oxidative products correlated to a much higher degree with the level of severity than the duration. There were significant decreases in the contractile responses in the mild decompensation group, whereas the level of derivatized into dinitrophenyl and nitrotyrosine of the muscle remained at control levels. This was not the case for the 4 weeks obstructed group.

CONCLUSIONS

These findings suggest that the etiology for the mechanism of contractile dysfunction is not an oxidative stress.