Nitric Oxide Synthase Expression in Rat Anorectal Tissue after Sacral Neuromodulation

Abstract

Sacral neuromodulation is becoming established as a valid treatment option for patients with anorectal disorders. Nevertheless, despite its efficacy, little is known regarding its mechanism of action. The purpose of this study was to evaluate whether chronic sacral neuromodulation is able to influence the expression of nitric oxide synthetase (NOS) in the anorectum of rats. Twenty-six female Sprague-Dawley rats were divided into three groups; normal control rats (n = 6); sham treatment (n =10) and group in whom, electrical sacral neuromodulation was performed (n = 10). Bilateral electrode wires were placed in the S1 and electrical stimulation was performed for 14 d. At the end of the procedures the rats were sacrificed, proctectomy was performed, and anorectal specimens were sent to the laboratory for immunostaining with n-NOS and i-NOS. In the anal and rectal specimens, n-NOS and i-NOS expression was significantly increased in epithelial and muscle cells after neuromodulation of the anus and rectum of the animals. Our results showed that this model can be applied in further experimental studies to better understand the mechanism of action of sacral neuromodulation in anorectal disorders.