Abstract

Objective To investigate the protective effect of green tea epigallocatechin gallate (EGCG) on long-term ketamine-induced ulcerative cystitis (KIC) using a ketamine addiction rat model.

Materials and methods Thirty Sprague-Dawley rats were divided into three groups which received saline, ketamine (25 mg/kg/d), or ketamine combined with EGCG (10 μM/kg) for a period of 28 days. In each group, cystometry and a metabolic cage micturition pattern study were performed weekly. Masson's trichrome study was done to evaluate the morphologic changes. Western blot analyses were carried out to examine the expressions of inflammatory protein [transforming growth factor-β (TGF-β)] and fibrosis proteins (fibronectin and type I collagen) in bladder tissues.

Results Chronic ketamine treatment resulted in bladder hyperactivity with a significant increase in micturition frequency and a decrease in bladder compliance. These alterations in micturition pattern were accompanied by increases in the expressions of inflammatory and fibrosis markers, TGF-β, fibronectin, and type I collagen after long-term ketamine treatment. Masson's trichrome stain showed that ketamine treatment decreased urothelium thickness while increasing the collagen to smooth muscle ratio and exacerbating interstitial fibrosis. By contrast, simultaneous EGCG and ketamine treatment reversed ketamine-induced damage to almost control levels, showing the protective effect of EGCG.