Time dependent bladder apoptosis induced by acute bladder outlet obstruction and subsequent emptying is associated with decreased MnSOD expression and Bcl-2/Bax ratio

Ischemia/reperfusion (I/R) injury-induced oxidative stress plays an important role in the functional impairment of the bladder following acute bladder outlet obstruction (BOO) via induction of apoptosis. The purpose of this study was to investigate the time course of the bladder apoptosis, and apoptosis related molecular changes in the early stage of acute BOO. Twelve-week-old male Sprague Dawley rats were divided into control, acute BOO only (I), and acute BOO plus subsequent emptying (I/R) for 30, 60, 120 min, 3 days and 2 weeks. We examined the extent of bladder apoptosis, expression of Mn-superoxide dismutase (Mn-SOD), Bcl-2, Bax, caspase 3 and poly (ADP-ribose) (PAR) in the bladder. Bladder apoptosis was significantly increased in the I/R group at 30, 60, and 120 min following bladder emptying. BOO plus subsequent emptying for 30, 60, 120 min showed significant decrease in MnSOD and Bcl-2 expression, and significant increase in caspase 3, Bax expression, and amounts of PAR. These results indicate that bladder apoptosis, induced by acute BOO and subsequent emptying, is associated with decreased MnSOD expression, increased PARP activity and imbalance in apoptosis pathways.