AIM:To investigate the effect and mechanism of candesartan(Can) for diabetic retinopathy(DR) in rats.METHODS:Of 45 male SD rats,8 rats were obtained at random as normal control group.The diabetic rat model was built by tail vein injection of streptozotocin(STZ).Except for 5 died or not successful model rats,successful model rats were randomly divided into diabetes group,Can treatment group,insulin treatment group,Can and insulin treatment group.Per group had 8 rats.The plasma AngⅡ was determined by radioimmunoassay,and retinal AT1R,NF-κB protein expressions were measured by immunohistochemistry.RESULTS:The plasma AngⅡ increased in all groups.Compared with diabetes group,insulin treatment group decreased significantly,and Can treatment group increased significantly.Normal control group had little AT1R,NF-κB protein expression.The expression of AT1R,NF-κB protein levels increased significantly in diabetes group.It all decreased in these treatment groups,and it decreased significantly in Can and insulin treatment groups.CONCLUSION:Can can inhibit the combination of Ang Ⅱ and AT1R,and it decreases the expression of AT1R,NF-κB protein levels.Therefore,candesartan has protective effect on DR.