The effect of botulinum toxin and resiniferatoxin on the detrusor overactivity induced by cyclophosphamide in rat bladder

Purpose: The purpose of this study was to compare the effects of resiniferatoxin (RTX) and botulinum toxin (BTX) on the bladder detrusor function in a cyclophosphamide (CYP)-induced cystitis rat model. Materials and Methods: Sprague-Dawley rats were divided into 5 groups (1: saline treated, 2: CYP and BTX treated, 3: CYP and RTX treated, 4 and 5: CYP treated and sham operated as the counterpart of groups 2 and 3, respectively, with normal saline). 100mg/kg CYP was injected every third day for five weeks. Cystometrograms were performed after the BTX and RTX treatments. Results: 1. The normal control group and the CYP-treated only group. In the CYP-treated group, the time of micturition frequency, the maximal detrusor pressure on the cystometergram (Pvesmax at CMG), the maximal detrusor pressure on the pressure-flow study (Pvesmax at pr/flow) and the episodes of irregular contractions were increased. 2. The CYP-only group and the CYP/BTX or CYP/RTXtreated groups. In the CYP/BTX or CYP/RTX treated groups, the time of micturition frequency, the Pvesmax at CMG, the Pvesmax at pr/flow and the episode of irregular contractions were decreased. 3. The CYP/BTXtreated group and the CYP/RTXtreated group. There was no statistically significant difference between the two groups regarding micturition frequency, the PvesMax at CMG and the PvesMax at pr/flow, the Dhfo and the episodes of involuntary contractions (p>0.05). Conclusions: Intravesical administration of BTX or RTX blocked the CYP-induced detrusor overactivity as was shown by the restoration of the micturition frequency, the intravesical pressure and the involuntary contraction episodes to a control level. There was no statistically significant difference between the two groups regarding the urodynamic parameters.