Abstract: To study the protective effect and potential mechanism of capsaicin on renal ischemia reperfusion injury (I/R).The SD rats were divided into Sham group,model group,low dose capsaicin group (4 μg/kg),middle dose capsaicin group (8 μg/kg),and high dose capsaicin group (16 μg/kg).The capsaicin grorps were pretreated with capsaicin（4、8、16）μg/kg at 45 min before ischemia by intraperitoneal injection.The Sham and model grorps were pretreated with the equal volume of saline at 45 min before ischemia by intraperitoneal injection..The content of ATP、ADP、AMP and ATP +ADP +AMP in mitochondrialof kidney were examined by high performance liquid chromatography;The content of creatinine (Cr) and urea nitrogen (BUN) in serum were evaluated by ELISA;PAS staining was used to measure renal pathological injury;The activity of Ca^{2 +}-ATP and Na⁺-K⁺-ATP in mitochondrial were evaluated by enzymatic method;The content of malondialdehyde (MDA) in mitochondrial was examined by thiobarbituric acid colorimetric method (TBA);The activation of superoxide dismutase (SOD),glutathione peroxidase (GPx) and catalase (CAT) in mitochondrial of kidney were detected by xanthine oxidase and Colorimetry,respectively.Western bloting was used to mesuare the expression of p-TRPV1 and TRPV1.The results showed that:compared with Control group,the model group has higher expression of p-TRPV1,more content of Cr、BUN and MDA and more serious renal pathological injury with lower activity of SOD、GPx、CAT、Ca^{2 +}-ATP and Na⁺-K⁺-ATP and ATP、ADP、AMP and ATP +ADP +AMP content in mitochondrialof kidney with no difference on the TRPV1expression;compared with the model group,the capsaicin pretreatment can significantly reduce the content of Cr,BUN and MDA and the pathological damage of kidney with significantly increasing activity of SOD、GPx、CAT、Ca^{2 +}-ATP and Na⁺-K⁺-ATP and higher content of ATP、ADP、AMP、ATP +ADP +AMP and p-TRPV with no difference on the TRPV1expression;Therefore,capsaicin can protect rats against renal ischemia reperfusion injury which is associated with inhibition of kidney mitochondrial lipid peroxidation.

Key words: capsaicin, renal ischemia reperfusion injury, mitochondrial, lipid peroxidation