Objective To observe the protective effect and mechanism of Astragalus Injection and vitamin E on renal ischemia reperfusion injury in rats.Methods The SD rats were randomized into five groups:sham operated-group

model group

Astragalus group

vitamin E group

and Astragalus plus vitamin E group

with 15in each.The ischemia-reperfusion injury models were made by restoring blood flow after removal of right kidney and clipping the left renal artery for an hour with artery clip.The Astragalus group and vitamin E group were injected Astragalus injectio 10mg/kg and vitamin E 100mg/kg respectively one hour before operation

and the Astragalus plus vitamin E group was treated with both simultaneously.The levels of serum blood urea nitrogen（BUN）

creatinine（Cr）

urinary kidney injury molecule-1（KIM-1）

6-acetyl-β-D-glucosaminidase（NAG）

and the activity of superoxide dismutase（SOD）and malondialdehyde（MDA）of renal tissues of all groups were detected one hour after ischemia

one hour and twenty-four hours after reperfusion respectively and dynamically

and the pathological changes in HE staining of renal tissues were observed as well.Results Compared with model group

the 3treatment groups had significant decrease in the levels of serum BUN and Cr

decrease in the levels of KIM-1and NAG

increase in the activity of SOD

and decrease in the level of MDA（P<0.05or P<0.01）.The comparison of the 3treatment groups showed significant difference（P<0.05）.The pathological changes of the renal tissues existed in model group

i.e.a large number of renal tubular epithelial cells became swollen and necrosis

and there was liquid protein and red blood cells or cell fragments in the renal tubular cavity.The pathological changes of the renal tissues in the treatment groups were significantly relieved.Conclusion Astragalus injection and vitamin E may enhance the activity of SOD

clear oxygen free radicals

and reduce lipid peroxidation

having aprotective effect on ischemia-reperfusion kidney.Astragalus injection may be superior to vitamin E in the protective effect

and the combination of both is better in result.