Abstract:Objective To observe the effects of melatonin（MT） on oxidative stress and inflammation state of renal mitochondria after renal ischemia reperfusion injury（IRI） in rats. Methods Sixty SD rats were randomly divided into sham-operation group（Sham group, n =10）, ischemia reperfusion group（IR group, n =25） and ischemia reperfusion plus MT（3.0 mg/kg） group（MT 3.0 mg group, n =25）. At 6- and 24-hour after successful establishment of ischemia-reperfusion model, venous blood was taken to detect the levels of serum urea nitrogen（BUN） and serum creatinine（Scr）. The upper pole of one kidney was taken for HE staining specimen to observe the renal histomorphological changes（the score of renal tubule injury degree evaluated by Paller method） and the protein expressions of tumor necrosis factor-α（TNF-α） and interleukin-6（IL-6） by immunohistochemistry. The renal cortex homogenate from the other unilateral kidney was prepared for extracting mitochondria, which was used for the detection of the levels of TNF-α, high-sensitive C-reactive protein（hs-CRP）, IL-6, malondialdehyde（MDA）,glutathione peroxidase（GSH-Px） and superoxide dismutase（SOD） by Enzyme linked immunosorbent assay. Results After 6- and 24-hour of ischemia-reperfusion, compared with those in Sham group at each time point, the levels of BUN and Scr, Paller score, the expressions of IL-6 and TNF-α in renal tissue and the levels of hs-CRP,TNF-α, IL-6 and MDA in renal mitochondria significantly increased（ P ＜0.01）, and the levels of GSH-Px and SOD decreased in IR group（ P ＜0.01）; compared with those in IR group at each time point, the above indicators showed reverse changes in MT 3.0 mg group（ P ＜0.01）. Conclusion MT can attenuate the oxidative stress and inflammatory of renal mitochondria during ischemia-reperfusion, effectively alleviate renal IRI and improve renal function.