Na ~ +-H ~ + Exchange Inhibitors And Na To + Channel Blockers On Ischemia / Reperfusion Injury In Experimental Studies Of Myocardial Protection

Objective To study the effects of Na+-H+ exchange inhibition and Na+ channel blocker on myocardial ischemia/reperfusion (I/R) injury, the suitable concentration, the symphysial effects and as well as the mechanism. Methods the isolated perfused working heart models of SD-rats were randomly dilated into 3 experiment groups (A, B and C). A included 4 groups (n=24, 6 in each group): control group (st. Thomas II), H5 group (HOE642 5μmol/L+ st. Thomas II), H10 group (HOE642 10μmol/L+ st. Thomas II), H20 group (HOE642 20μmol/L+ st. Thomas II). B included 4 groups(n=24, 6 in each group): control group(st. Thomas II), H20 group (HOE642 20μmol/L+ st. Thomas II), M group (Mexibetine 70μmol/L+ st. Thomas II), HM group (HOE642 20μmol/L+ Mexibetine 70μmol/L+ st. Thomas II). The percent recovery of heart function and water content ofmyocardial were determined after I/R both in group A and B. C was composed of 4 groups (n=24, 6 in each group) as B but the dugs were added at the earlier period of reperfusion. Results The percent recovery of heart function was significantly increased and water content of myocardial was significantly decreased in group H10 and group H20 contract as the other two groups in group A. The percent recovery of heart function was significantly increased and water content of myocardial was significantly decreased in group H20 and group HM (except group M) contracted as the control groups in group B. There were not significant among groups in group C. Conclusions The myocardial protection of st. Thomas II can be strengthened while HOE642, a Na+-H+ exchange inhibition, is added as 10~20μmol/L concentration. The myocardial protection of st. Thomas II cannot be strengthened with Mexibetine (70μmol/L), a Na+ channel blocker. The effects of Na+-H+ exchange inhibition will be greatly strengthened by Na+ channel blocker. The myocardial protections cannot be obtained while Na+-H+ exchange inhibition and Na+ channel blocker are used at reperfusion period.Key words Na+-H+ exchange inhibition,Na~+ channel blocker ischemia/reperfusion...