Different Doses Of L-arginine On Myocardial Stunning In Rabbit Myocardial Protection

Objective: To explore the effects of L-arginine(L-Arg) on mature rabbits with myocardial stunning(MS) in vivo. Methods: Fifty six rabbits were randomly divided into 7 groups (8 in each). During ischemic,L0 group, injected with physiological saline(10ml/kg/min); L2 group, injected with L-Arg (2mg/kg/min); L4 group, injected with L-Arg (4mg/kg/min); L8 group, injected with L-Arg (8mg/kg/min) ; L16 group, injected with L-Arg (16mg/kg/min); L32 group, injected with L-Arg (32mg/kg/min); L64 group, injected with L-Arg (64mg/kg/min). The model of MS was established by occluding the branch of left anterior descending artery(LAD) for 15min followed by 60 min reperfusion.Parameters on cardiac function were measured before ischemia and during ischemia and reperfusion. Content of malodialdehyde(MDA) and cardiac troponin I (cTnI) was investigated in 60 min after reperfusion. Results: (1) The stunned state developed in all rbbbits after 15 min of ischemia in forms of decreased of cardiac function.(2)L8 group achieved better recovery of cardiac function than the other 6 groups,and poorer recovery of MDA and cTnI contents.(3)Injected L-Arg during ischemia markely reduced the disturbance of hemodynamic and improved cardiac function. Conclusion: During ischemic NO precursor(L-Arg) could improve the cardiac function of the stunned myocardium. L-Arg could protect myocardium from ischemica/reperfusion injury significantly injected with L-Arg 8 mg/kg/min.