Protection Effect And Its Mechanism Of Isoquercetin Pretreatment Against Renal Ischemia/Reperfusion Injury In Mice

Background:Renal ischemia reperfusion/injury(RIRI)is one of the common clinical problems,which exists in a variety of pathophysiological processes.The pathophysiology of RIRI is very complex.Inflammatory response,oxidative stress and apoptosis are considered to play important roles in the process of RIRI.Isoquercetin(IQ)occurs naturally in many kinds of plants.Previous studies have found that IQ can protect cerebral ischemia-reperfusion injury via anti-oxidation,anti-inflammatory and anti-apoptosis.However,the role of IQ in RIRI has not been reported.Objective:To investigate the effects of IQ on RIRI in mice and explore its possible mechanism.Methods:(?)Thirty wild type C57BL/6 male mice(10 weeks old,22-24 g)were randomly divided into 3 groups(10 mice per group)as follows:group A:sham operation(Sham);group B:RIRI model group;and group C:IQ pretreatment+RIRI(IQ+ RIRI)group.For the RIRI model group,the left kidney pedicle was clamped for 30 minutes following right nephrectomy to make the left kidney ischemic,then the left renal pedicle clamp was removed and reperfusion for 24 hours.For the IQ+RIRI group,mice were given intraperitoneal injection of 20 mg/kg IQ once a day for 3 successive days before operation,followed by ischemia-reperfusion.(?)The concentrations of creatinine and blood urea nitrogen(BUN)in serum were measured using commercially available kits,and the pathological changes of renal histology were observed by HE staining.(?)Through the detection of myeloperoxidase(MPO)activity,and levels of IL-6 and TNF-? in renal tissue,the effect of IQ pretreatment on the role of inflammatory response in RIRI in mice was evaluated.Western blot analysis and immunohistochemistry staining were used to detect the expression of NF-?B in renal tissue and explore the possible mechanism of inflammatory response.(?)Via the detection of SOD,GSH,CAT and MDA in renal tissue,the effect of IQ pretreatment on the role of oxidative stress in RIRI in mice was assessed.(?)Through the detection of caspase-3,caspase-8,caspase-9 activity and the expression of Bcl-2,Bax protein in renal tissue,the effect of IQ pretreatment on the role of apoptosis in RIRI in mice was evaluated.Results:(?)Compared with RIRI group,IQ pretreatment significantly reduced the level of blood urea nitrogen,blood creatinine and renal tissue damage score after RIRI.(?)Compared with RIRI group,IQ pretreatment significantly reduced the activity of MPO,the level of the inflammation related factor IL-6,TNF-? and the expression of NF-?B in renal tissue.(?)Compared with RIRI group,IQ pretreatment significantly increased the activity of oxidative stress relating indicators(SOD,GSH,CAT),and reduced the level of MDA,an end product of lipid peroxidation.(?)Compared with RIRI group,IQ pretreatment significantly reduced the activity of caspase-3,caspase-8,caspase-9,increased the expression of Bcl-2.In addition,IQ pretreatment markedly downregulated the expression of Bax and upregulate Bcl-2/Bax.Conclusion:(?)IQ can attenuate RIRI in mice,indicating its protective effect on the kidney.(?)IQ can alleviate RIRI by inhibiting inflammatory response,which may be mediated by down-regulation of NF-?B pathway.(?)IQ can relieve RIRI in mice through anti-oxidation.(?)IQ can mitigate RIRI by anti-apoptosis,which may be mediated by regulating the members of Bcl-2 family and caspase family.