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).

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.

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.

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.