Apoptotic Action of Botulinum Toxin on Detrusor Muscle in Rats

Abstract

Aims: To examine botulinum toxin A (BTX-A)-induced apoptosis in the detrusor muscle in male rats. Methods: The bladder wall and prostate in adult male Sprague-Dawley rats were injected with BTX-A (10 U at each site). Tissues were harvested after 2 weeks, then the effects of BTX-A on proliferative and apoptotic indices were determined using proliferative cell nuclear antigen and TUNEL staining, respectively. In addition, real-time polymerase chain reaction was used to measure mRNA expressions of the apoptosis-related gene, bcl-2, and BAX in detrusor muscle. Results: Although bladder weight was significantly increased in the BTX-A group compared to controls, no significant changes in prostate weight were identified. While significant increases in proliferative cells were apparent in the vesical mucosa after staining, no significant changes were noted in apoptotic or proliferative cells in detrusor muscle or prostate. In addition, no significant changes between the BTX-A group and controls were seen for mRNA expressions of bcl-2/β-actin or BAX/β-actin in detrusor muscle. Conclusions: The lack of significant changes in cellular dynamics of the detrusor muscle in the current study suggests that BTX-A injection into detrusor muscle for overactive bladder may not induce bladder atrophy.