Effects of β3-adrenoceptor agonist on acute urinary retention in a rat model.

Abstract

To investigate the protective effect of mirabegron on bladder dysfunction in an acute urinary retention rat model. Thirty-six 16-week Sprague-Dawley rats were assigned to the mirabegron and normal saline (N/S) groups. Each group of eighteen was divided into sub-groups of 6 for 30min, 2h, and 24h. They were administered mirabegron (10mg/kg) and N/S daily for 4weeks, respectively. Mirabegron and N/S groups were divided into sub-groups of 6 rats for 30min, 2h, and 24h. The changes in bladder blood flow were measured using laser Doppler (moorVMS-LDF2). Histopathological examination of the bladder and nitric oxide (NO) measurement were performed. During the urinary retention phase in the mirabegron group, it showed higher and rapider recovery of blood flow; the lowest at 19.5% ± 3.68% at 3min, a significant recovery from the lowest value as 23.7 ± 3.4% at 10min, than that in the N/S group; 15.1 ± 1.84% at 5min, 23.7 ± 3.4% at 20min, respectively (P < 0.05). At 30min, 120min, and 24h after reperfusion, the recovery of blood flow in the mirabegron group was significantly higher than that in the N/S group (mirabegron: 41.1 ± 1.7%, 59.9 ± 7.2%, and 89.7 ± 4.4%, N/S: 31.3 ± 2.1%, 47.3 ± 4.5%, 83.9 ± 3.6%, respectively (P < 0.05)). NO levels tended to be higher in the mirabegron group; however, the difference was not statistically significant. Histological examination revealed that the mirabegron group showed recovery close to normal tissue after 24h. In an acute urinary retention rat model, mirabegron maintained and restored higher bladder blood flow, resulting in protective and recovery effect after acute urinary retention.