Abstract: Objective To study the effect of Tanshinone ⅡA(Tan ⅡA) on the contents of nitrous oxide(NO) and the activities of nitric oxide synthase(NOS) and immunologic NOS(iNOS) following cerebral ischemia reperfusion(I/R)injury in rats.Methods 40 Wistar rats were randomly divided into 4 groups,which were sham group,I/R group,low dosage Tan ⅡA treated group and high dosage Tan ⅡA treated group.The focal middle cerebral artery occlusion(MCAO) model was made.Rats were pretreated with Tan ⅡA for 3 d respectively before MCAO.After 90 min MCAO following 24 h of reperfusion,HE staining was investigated.The contents of NO and the activities of NOS and iNOS were also investigated.Results The change of ischemic impairment in low or high dosage Tan ⅡA treated group was lighter than that of I/R group,and high dosage Tan ⅡA treated group was lighter than that of low dosage Tan ⅡA treated group.Compared with the sham group,the contents of NO and the activities of NOS and iNOS increased in the ischemic territory(P<0.05).Compared with I/R group,low and high dose Tan ⅡA treated group reduced the contents of NO and the activities of NOS and iNOS dose-dependently(P<0.05).Conclusion Tan ⅡA may reduced cerebral ischemia-reperfusion injure by reducing the contents of NO and the activities of NOS and iNOS dose-dependently.

Key words: ischemia-reperfusion, nitrous oxide(NO), nitric oxide synthase(NOS), immunologic NOS(iNOS), Tanshinone ⅡA