Effects of the phosphodiesterase 5 inhibitor Tadalafil on bladder function in a rat model of partial bladder outlet obstruction.

Abstract

To investigate the effect of the phosphodiesterase 5 (PDE5) inhibitor Tadalafil on bladder blood flow and bladder function in a rat model of partial bladder outlet obstruction (BOO). Female 14-15-week-old Sprague-Dawley rats were divided into three groups. BOO was surgically induced in rats by placing a rubber ring around the urethra. BOO rats were administered daily oral Tadalafil (BOO-Tadalafil) or vehicle (BOO-Vehicle), while sham-operated animals were treated with vehicle (Sham). On the 14th day after surgery, micturition behavior was recorded for 24 hr by using a metabolic cage. On the 15th day after surgery, bladder blood flow and bladder weight were measured. The expression of PDE5 mRNA in the vesical and iliac arteries of intact rats was measured by reverse transcriptase-polymerase chain reaction. BOO led to a significant decrease in bladder blood flow and a significant increase in bladder weight. These changes were partially suppressed by Tadalafil treatment. The number of micturitions in the BOO group was significantly increased and the average micturition volume was significantly decreased, without affecting the total micturition volume. Repeated Tadalafil treatment markedly inhibited the increase in micturition frequency and the decrease in average micturition volume. PDE5 mRNA was expressed in the vesical and iliac arteries. Tadalafil suppressed the reduction in bladder blood flow caused by BOO in rats and improved urinary function. This action of Tadalafil may contribute to its amelioration of bladder function. Neurourol. Urodynam. 35:444-449, 2016. © 2015 Wiley Periodicals, Inc.