Recovery From Short-Term Obstruction of the Rabbit Urinary Bladder

Abstract

Partial bladder outlet obstruction is a commonly encountered pathophysiologic state. Recently we have reported on the rapid nature of the contractile and functional changes that occur in the rabbit urinary bladder within one week of chronic partial obstruction. The purpose of this present study is to investigate the ability of the bladder to recover from one week of partial obstruction. Twenty-six mature male white New Zealand rabbits were separated into 3 groups. Each rabbit was anesthetized with ketamine-xylazine and a partial obstruction of the bladder established by gently securing a 2.0 silk suture around the temporarily catheterized bladder neck. The rabbits in group 1 were sacrificed following one week of partial obstruction. For groups 2 and 3, the obstructing suture was surgically removed after one week of obstruction and the rabbit was allowed to recover for either two or four weeks. At the end of one week of obstruction the bladder displayed a 9-fold increase in tissue mass, 50 per cent reduction in contractile response to bethanechol and a 76 per cent reduction in the ability of the bladder to expel saline. After the two week recovery period, the bladder mass was reduced to approximately twice the control mass, the contractile and pressure responses to bethanechol were returned to control levels, and the ability of the bladder to expel saline recovered to approximately 75 per cent of control levels. No further improvements were observed following the four week recovery period. It appears that although the contractile response recovers completely following the one week obstruction period, the ability of the bladder to empty remains partially impaired.