Effects of Hirudin on Ventricular Arrhythmia after Acute Myocardial Infarction in Rats / 中山大学学报(医学科学版)

ABSTRACT

[Objective] To determine the effects and possible mechanism of the thrombin antagonist r-RGD-Hirudin (HIR) on ventricular arrhythmia(VA) after acute myocardial infarction (AMI). [Methods] Seventy adult male Sprague-Dawley rats were randomly subjected to the 10 groups according to duration of left coronary occlusion HIR 0 min, HIR 5 rain, HIR 10 min, HIR 20 min, HIR 30 min, and normal saline(NS) 0 min, NS 5 min, NS 10 min, NS 20 min, NS 30 min; and the average of every group is 7 rats. Acute myocardial infarction was produced by the occlusion of the left anterior descending coronary artery, then the measurements of arrhythmia and infarction sizing by Evans blue were assessed as well as the expression of three isoforms of inositol 1,4,5-trisphosphate receptors (IP3Rs) mRNA in isehemic myocardium by reverse transeriptase polymerase chain reactions (RT-PCR). [Results] Compared with NS groups, the measurements of VA in HIR were reduced significantly in 5 to 20 minutes after AMI (P<0.05). The incidence of VA was all positive related to the expression of three isoforms of IP3Rs mRNA (P<0.01). Compared with NS groups, the expression of type2,inositol 1,4,5-trisphosphate receptor (IP3R2) mRNA at 10 min and type3, inositol 1,4,5-trisphosphate receptor mRNA (IP3R3) at 10 min and 20 min after AMI were significant decreased (P<0.05) in HIR groups. [Conclusion] The thrombin antagonist r-RGD-Hirudin exerts its myocardial protection against ventricular arrhythmia after acute myocardial infarction possible through IP3R2 and IP3R3 and not typel, inositol 1,4,5-trisphosphate receptor (IP3R1).