Effect of L-carnitine on heart function following myocardial contusion in mongrel dogs / 中华创伤杂志

ABSTRACT

Objective To investigate the effect of L-carnitine (LCN) on heart function following myocardial contusion in mongrel dogs.Methods Twenty-four male mongrel dogs were randomly divided into myocardial contusion group,low dose LCN group (LCN1 group),and high dose LCN group (LCN2 group) with 8 dogs per group,according to the random number table.The model of myocardial contusion was established in all groups.LCN1 and LCN2 groups were respectively treated with 100 mg/kg and 200 mg/kg LCN for three consecutive days before the injury and afterward.Left ventricular systolic pressure (LVSP),left ventricular end diastolic pressure (LVEDP),left ventricular ± dp/dt were recorded 30 min before injury,and 30 min,1 h,2 h,4 h as well as 6 h after injury.Blood samples were withdrawn from femoral vein to detect the levels of creatine kinase isozyme (CK-MB),cardiac troponin I (cTnI),and malondialdehyde (MDA).Wall motion score index (WMSI) was observed using the ultrasound examination 1 day before and 5 hours after injury.Myocardial tissue was available at 6 hours after injury for the examination of content of adenosine triphosphate (ATP).Results LVSP and ± dp/dtmax appeared a downward trend after injury,while a gradual increase in LVEDP.And the changes were relatively smaller with LCN intervention,especially in LCN2 group.Levels of CK-MB,cTnI and MDA increased after injury,but the same time point showed lower levels in LCN groups (especially in LCN2 group) as compared to myocardial contusion group (P ＜ 0.05).WMSI increased 5 hours after the injury,but the increase was higher in myocardial contusion group (2.46 ±0.31) than that in LCN1 group (1.91 ± 0.23) and LCN2 group (1.85 ± 0.25) (P ＜ 0.05).There was no significant difference in WMSI between the two LCN groups (P ＞ 0.05).Level of ATP in myocardial contusion group was (11.3 ± 1.6) μg/g,which was improved after LCN intervention (P ＜ 0.05),and the improvement was much higherin LCN2 group than in LCN1 group[(21.3±3.9) ug/g vs (15.7±2.8)ug/g] (P＜0.05).Conclusion LCN can alleviate the adverse effect of myocardial contusion on cardiac function in mongrel dogs,which may be associated with the reduced energy imbalance induced by LCN.