Melatonin protects kidney against apoptosis induced by acute unilateral ureteral obstruction in rats

INTRODUCTION To investigate whether there was a protective effect of melatonin on apoptotic mechanisms after an acute unilateral obstruction of the kidney. MATERIAL AND METHODS A total of 25 rats consisting of five groups were used in the study, designated as follows: Group 1: control, Group 2: sham, Group 3: unilateral ureteral obstruction treated with only saline, Group 4: unilateral ureteral obstruction treated with melatonin immediately, and Group 5: unilateral obstruction treated with melatonin one day after obstruction. Melatonin was administered as a 10 mg/kg dose intraperitoneally. The kidneys were evaluated according to the apoptotic index and Ki-67 scores. RESULTS Comparison of all obstruction groups (Group 3, 4, and 5), revealed that the apoptotic index was significantly higher in Groups 1 and 2. Despite melatonin reduced apoptotic mechanisms in Groups 4 and 5, there was no significant difference between Groups 4 and 5 in terms of the reduction of apoptosis. However, the reduction of apoptosis in the melatonin treated group did not decrease to the level of Groups 1 and 2. CONCLUSIONS Despite melatonin administration, which significantly reduces the apoptotic index occurring after acute unilateral ureteral obstruction, the present study did not observe a return to normal renal histology in the obstruction groups.