AIMS: We evaluated effects of BoNT-A injections on bladder function and histomorphology in a male-rat-overactive-bladder model, created by partial urethral obstruction. METHODS: A total of 45 male Sprague-Dawley rats were separated into 5 groups. Partial urethral obstruction (PUO) was created in all rats except the control group. At the 6th week after PUO, intradetrusor injections of 50 µl of saline (2 sham groups) or 50 µl BoNT-A (2 treatment groups) was performed. Treatment and sham groups were studied 5 and 30 days after injection and neuropharmacological and histomorphological findings on bladder tissues were compared to the control group. RESULTS: Bladder muscle hypertrophy and connective tissue increase were detected at 5th and more prominent at 30th day after saline injection. Intradetrusor BoNT-A injection significantly reduced PUO-induced histological changes in the bladder tissue both at 5th and 30th day after injection. At 5th day after saline injection, a significantly increased contractile response to electrical field stimulation (EFS) and carbachol were recorded in the saline group and this effect disappeared at 30th day. There was no statistically significant difference between BoNT-A and control groups in terms of contractile responses to EFS and carbachol, both at 5th and 30th days. CONCLUSION: Partial urethral obstruction induces increased bladder tissue contractile responses to neurogenic and pharmacological stimulation and intradetrusor BoNT-A injections decrease these responses at 5th days after injection. As the unique finding of this study, intradetrusor BoNT-A injections appear to decrease bladder fibrosis secondary to PUO in the male rat model.
AIMS: We evaluated effects of BoNT-A injections on bladder function and histomorphology in a male-rat-overactive-bladder model, created by partial urethral obstruction. METHODS: A total of 45 male Sprague-Dawley rats were separated into 5 groups. Partial urethral obstruction (PUO) was created in all rats except the control group. At the 6th week after PUO, intradetrusor injections of 50 µl of saline (2 sham groups) or 50 µl BoNT-A (2 treatment groups) was performed. Treatment and sham groups were studied 5 and 30 days after injection and neuropharmacological and histomorphological findings on bladder tissues were compared to the control group. RESULTS: Bladder muscle hypertrophy and connective tissue increase were detected at 5th and more prominent at 30th day after saline injection. Intradetrusor BoNT-A injection significantly reduced PUO-induced histological changes in the bladder tissue both at 5th and 30th day after injection. At 5th day after saline injection, a significantly increased contractile response to electrical field stimulation (EFS) and carbachol were recorded in the saline group and this effect disappeared at 30th day. There was no statistically significant difference between BoNT-A and control groups in terms of contractile responses to EFS and carbachol, both at 5th and 30th days. CONCLUSION: Partial urethral obstruction induces increased bladder tissue contractile responses to neurogenic and pharmacological stimulation and intradetrusor BoNT-A injections decrease these responses at 5th days after injection. As the unique finding of this study, intradetrusor BoNT-A injections appear to decrease bladder fibrosis secondary to PUO in the male rat model.