Introduction and Objective: The main cause of acute kidney injury is reported to be renal ischemia.The present study aimed to histopathologically investigate the effects of experimental ischemia–reperfusion injury on the protective role of apelin in the oxidative damage occurred in rat kidneys compared to the group in which ischemic damage was not induced.

Materials and Methods: The experimental subjects were divided into two groups each of which included seven rats.  The blood flow of the renal vessels (arteries and veins) of the rats in the ischemia/reperfusion (IR)  experimentally group (=control group) was interrupted using a non–traumatic microvascular clamp for 60 minutes and ischemia was produced. In order to replace the indispensable fluid loss occurred while the abdomen was open, sterile saline weighing 5% of the body weight at 37°C was administered intra–abdominally during the experiment. The rats in both groups were kept alive in metabolic cages for 24 hours after the closing abdomen. After the reperfusion period ended, the left kidneys were removed and the rats were sacrificed.

Results: Statistically significant results were obtained by the Chi–Square test which was conducted to determine the difference between the staining intensity of the sham group and control group (p=0.015,p<0.001,p<0.001, respectively).The Mann–Whitney U test was used to determine the staining intensity. The medulla stained better than the cortex (p=0.006).

Conclusion: It is obvious that apelin has a protective role in experimental renal IR injury. This conclusion needs to be supported by clinical studies. Today, surgical procedures and organ transplantations have become very common.  We suggest that long–term, large population clinical trials are needed to prevent and treat renal I/R injury that may occur perioperatively, and we believe that this study of ours will shed light on future clinical trials.