Chronic partial bladder outlet obstruction does not impair erectile function in male rats

OBJECTIVE To evaluate, in a well-controlled study, the effect of surgically induced partial bladder outlet obstruction (PBOO) on male erectile function in a rat model. MATERIALS AND METHODS PBOO was created in 17 adult male Sprague-Dawley rats by partial ligation of the proximal urethra. Sham-operated and PBOO rats were evaluated for urodynamic and erectile function at 4-8 weeks after surgery. Erectile responses to electrical field stimulation (EFS) to the major pelvic ganglion, and to erectogenic agents (1,1-diethyl-2-hydroxy-2-nitroso-hydrazine, DEA-NO, and Y-27632) were evaluated and the area under the curve (AUC, a product of the intracavernous pressure and duration) was used to denote the erectile response. RESULTS Experimental PBOO in rats significantly increased the mean (sem) bladder weight, to 256 (25) mg in PBOO rats vs 123 (24) mg in sham controls, and the voiding frequency to 1.01 (0.1) voids/min vs 0.72 (0.14) voids/min in sham controls (P < 0.05). There was no significant difference between the erectile response to EFS, with a mean AUC in sham control rats at 1.5, 3.0 and 4.5 V of 2603 (372), 3200 (332) and 3357 (166), respectively, vs 2273 (183), 3794 (211) and 4177 (306) in PBOO rats (P > 0.05); or to the erectogenic agents, the AUC for DEA-NO being 9000 (975) in PBOO rats vs 13 201 (2756) in sham controls, and the AUC for Y-27 632 being 44 915 (2462) and 45 907 (7408), respectively (P > 0.05). There was greater immunoreactivity to RhoA in bladder and penile tissues of PBOO than control rats. CONCLUSION PBOO does not affect erectile function in rats. Additional mechanisms or pathways might be involved in lower urinary tract symptom-related erectile dysfunction in humans.