Silymarin attenuates the renal ischemia/reperfusion injury-induced morphological changes in the rat kidney.

Objectives: Renal ischemia/reperfusion (I/R) injury is associated with increased mortality and morbidity rates due to acute renal failure (ARF). Oxidative stress induced with renal I/R injury directly affects glomerular and tubular epithelium through reactive oxygen species. Several studies have been directed to the treatment of renal I/R injury. The aim of this study was to test the attenuation with silymarin (SM) treatment of renal I/R injury-induced morphological changes in the rat kidney.

Methods: A total of 32 adult male Sprague-Dawley rats were evaluated in four groups. Group I (sham), Group II (renal I/R), Group III (renal I/R injury + SM 50 mg per kg) and Group IV (renal I/R injury + SM 100 mg per kg) were designed to evaluate the dose-dependent effects of SM on the morphological changes of renal I/R injury. Renal I/R injury were induced with left renal pedicle occlusion for 45 min followed with reperfusion for 6 h under anesthesia. After induction of I/R injury, left nephrectomies were performed for histopathological examinations.

Results: After renal I/R injury, significant tubular dilatation, tubular vacuolization, pelvic inflammation, interstitial inflammation, perirenal adipose infiltration, tubular necrosis and glomerular necrosis (cortical necrosis) were observed. However, even with low dose SM in Group III (50 mg per kg SM), histopathological changes due to I/R injury were prevented.

Conclusions: The results of this study have demonstrated that SM significantly prevents renal I/R injury-induced renal tubular changes in the rat. SM in 50 mg/kg was observed to be sufficient to significantly prevent renal tubular necrosis. Further, to our literature knowledge, this is the first specific study to demonstrate the preventive effect of SM on renal I/R injury.