Intravesical electromotive botulinum toxin type A administration: Part I - Experimental study

Objectives: To evaluate the depth and pattern of botulinum toxin type A (BTX-A) distribution throughout the rabbit bladder wall by intravesical electromotive drug administration (EMDA). Methods: In an experimental study, 15 male healthy New Zealand white rabbits were allocated in 3 groups of BTX-A injection into the bladder wall, intravesical electromotive BTX-A administration (BTX-A/EMDA), and electromotive saline administration. In BTX-A injection group, a total dose of 10 IU/kg of BTX-A (Dysport) was injected into 10 sites of bladder detrusor muscle using a 6-Fr rigid cystoscope. In BTX-A/EMDA group, a current generator delivered a total of 2-2.4 mA with a frequency of 2.5 kHz to a fully distended bladder containing 10 IU/kg BTX-A for 15 minutes. In electromotive saline administration group, electrical current with the same characteristics was delivered to a saline-filled bladder. Three different specimens from the bladder dome, posterior, and anterior bladder walls were obtained and submitted for pathologic evaluation. Results: Pattern of immunohistochemical staining in bladder specimens from BTX-A injection group was weak and heterogeneous in the urothelium, interstitium, and muscular layers. However, in BTX-A/EMDA group the staining was uniform in urothelium, interstitial and muscular layers in all submitted specimens. In electromotive saline administration group, the urothelium, interstitium, and muscular layers were intact. Conclusions: There is no clinical or experimental report of intravesical BTX-A/EMDA in the literature. This method demonstrated deep and homogenous penetration of the toxin throughout the urinary bladder layers compared with the intravesical BTX-A injection.