Comparative analysis of different cyclosporine A doses on protection after myocardial ischemia/reperfusion injury in rat

ABSTRACT

OBJECTIVE@#To investigate the protective effect of different cyclosporin A (CsA) doses on myocardial ischemia/reperfusion injury in rat models.@*METHODS@#A rat model of myocardial ischemia/reperfusion injury was established in vivo and the rats were randomly divided into four groups placebo (PBS; T1), low-dose (CsA dose 1.0 mg/kg; T2), medium-dose (CsA dose 2.5 mg/kg; T3), and high-dose (CsA dose 5.0 mg/kg; T4) groups. Heart function indexes were monitored at different time points, the extent of myocardial infarction was assessed by Evans Blue-TTC staining, and creatine kinase MB mass and cardiac troponin I values were measured by biochemical assays.@*RESULTS@#Compared with the T1 and T2 groups, both the creatine kinase MB mass and cardiac troponin I were significantly lower in the T3 and T4 groups (P<0.05). The mean arterial pressure (MAP) and left ventricular systolic pressure (LVSP) decreased sequentially in each group, with the extending reperfusion time. Significant decreases in LVSP and MAP were observed in the T3 and T4 groups as compared to the T1 and T2 group (P<0.05), and the T2 group showed a significantly lower LVSP and MAP decline than the T1 group (P<0.05). Compared with the T1 group, the rats from the T2, T3, and T4 groups suffered from a significantly lower extent of myocardial infarction (P<0.05). Also, the animals in the T3 and T4 groups had a significantly smaller extent of myocardial infarction than those in the T2 group (P<0.05).@*CONCLUSIONS@#Various CsA doses exert different degrees of protection against ischemia/reperfusion injury, and this protective effect peaks at approximately 2.5 mg/kg in rat models.