Objective To study the expression of Smad 2 and Smad 4 proteins in brain tissue following cerebral ischemia/reperfusion(IR)in gerbils.Methods Forty gerbils were randomly assigned to three groups:normal control,sham-operated and IR.The expression of Smad 2 and Smad 4 proteins in brain tissue was detected using immunohistochemistry technique 6 and 24 hrs after IR.Results Smad 2 and Smad 4 proteins were expressed in neurons and gliacytes of brain tissue,and expression of Smad 4 protein was significantly higher than Smad 2 protein in the three groups(P0.05).Compared with the normal control and the sham-operated groups,the expression of Smad 2 and Smad 4 proteins in neurons and gliacytes in the IR group increased significantly 6 and 24 hrs after IR(P0.05).Conclusions The expression of Smad 2 and Smad 4 proteins in neurons and gliacytes increased following cerebral IR in gerbils,suggesting that Smad 2 and Smad 4 are involved in the development of cerebral ischemia in gerbils.