| ObjectiveTo explore the mechanisms of ischemia reperfusion injury (IRI) and the effects of Livin over-expression on IRI.Methods69 Sprague-Dawley (SD) rats were divided into Sham group, ischemia reperfusion (IR) group and Livin group randomly. Rats in IR and Livin groups were subjected to 45min of left coronary artery occlusion followed by 120min of reperfusion. Rats in Livin group were treated with retrovirus vector expressing Livin protein by intramyocardial injection 24h before left coronary artery occlusion. The no-reflow area (NRA) was evaluated by injection of thioflavine S into the auticle of left atrium,and myocardial infarction size ( MIS ) was evaluated by triphenyltetrazolium (TTC) staining method at the end of reperfusion. Serum level of creatine kinase isozyme (CK-MB) was measured at the end of reperfusion. The myocardial apoptosis was determined with terminal deoxynucleotidyl transferase-mediated dUTP- fluorescein nick end labeling( TUNEL) method .Results(1) The myocardial perfusion in Sham group is sufficient,without no reflow phenomenon. No reflow area both in Livin group and in IR group were larger than that of Sham group. Compared with IR group, no-reflow area in Livin group was reduced significantly (19.39±6.25 vs 25.93±6.45,P<0.05). (2) Myocardial infarction size was significantly reduced in Livin group compared with IR group (22.14±2.98 vs 28.62±3.43,P <0.05), but either in Livin group or in IR group was larger than that of Sham group. (3) Serum level of CK-MB both in IR group and in L group were higher than that of Sham group,but Serum level of CK-MB in L group was lower than that of IR group. (4) we examined the presence of apoptosis during ischemia reperfusion, which was significantly higher in IR group and in Livin group compared with Sham group (11.52±2.58 vs 1.08±0.32, P <0.05). Apoptosis rate was significantly reduced after Livin injection (11.52±2.58 vs 5.05±1.74, P <0.05) .Conclusion(1) Apoptosis was increased in the process of myocardial ischemia reperfusion.(2) Livin over-expression can reduce NRA and MIS, inhibit myocardial apoptosis in the process of myocardial ischemia reperfusion.(3) Apoptosis participated in the process of myocardial ischemia reperfusion injury.By inhibiting myocardial apoptosis, Livin over-expression can protect the heart against ischemia reperfusion injury. |
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