OBJECTIVETo investigate the effect of ischemic reperfusion(I-R) on the expression of P-selectin(Ps) of platelets, CD11b of leukocytes, monocyte chemotactic protein-1(MCP-1) mRNA of myocardial tissue and the protective role of MgSO(4).

METHODSIschemic reperfusion rat model was established in the experiments. All animals were randomly divided into 3 groups sham group, I-R group and Mg(2+) group. The expression of Ps of platelets and CD11b of leukocytes was determined by flowcytometry and the expression of MCP-1 mRNA of myocardial tissue was measured by RT-PCR admission and at 5, 30, 60, 180, 360 min of reperfusion (R5, R30, R60, R180, R360).

RESULTSThe expression of Ps of platelets in I-R group began to rise at R5 and peaked at R60 P<0.01); the expression of CD11b of leukocytes was significantly higher than that of the control groups P<0.01 and P<0.05) the expression of MCP-1 mRNA of myocardial tissue began to rise at R60,reaching the highest at R360 P<0.01) the concentration of Ca(2+) of the serum was significantly higher than that of the control groups P<0.01 and P<0.05). MgSO(4) inhibited the expression of Ps of platelets and MCP-1 mRNA of myocardial tissue and decreased serum Ca(2+)concentration, but did not affect the expression of CD11b of leukocytes.

CONCLUSIONI-R can increase the expression of cell adhesion molecules and cell chemotactic factor. MgSO(4) may protect myocardial tissue from ischemic reperfusion injury by inhibiting the expression of Ps of platelets and MCP-1 mRNA of myocardial tissue and decreasing the concentration of Ca(2+) of the serum.