Beclin-1 expression is upregulated by spermine in rat myocardial ische-mia-reperfusion injury / 中国病理生理杂志

ABSTRACT

AIM:To observe the effects of spermine(SP)on myocardial ischemia-reperfusion(IR)injury in rats.METHODS:SD rats(weighing 220~250 g)were equally randomized to 3 groups sham control group, in which the rats were only treated with thoracotomy;IR group,in which the rats were treated with ischemia for 30 min and reperfu-sion for 60 min;and IR+SP group,in which 0.5 mmol/L SP(2 mL/kg)was intravenously injected just 15 min before reperfusion.The morphological changes of myocardial tissues were assessed by HE staining.The levels of cardiac troponin I(cTnI)and creatine kinase isoenzyme MB(CK-MB)in plasma were determined.Myocardial infarct size and no-reflow range of the myocardium were measured by Evans blue and thioflavin S staining.Inflammatory responses in the myocardial tissues were detected by myeloperoxidase(MPO)assay.The autophagy function was detected by measuring the protein ex-pression of beclin-1 by Western blot.RESULTS: The myocardial injury and inflammatory infiltration in IR +SP group were reduced under light microscope.Treatment with SP decreased the plasma levels of cTnI and CK-MB,and reduced the IR-induced infarct size and no-reflow range size of the left ventricle(P<0.05).Tissue MPO assay showed that myocardial inflammatory responses were attenuated in IR +SP group compared with IR group.Beclin-1 was upregulated in IR +SP group compared with IR group(P<0.05).CONCLUSION: Exogenous SP attenuates myocardial ischemia-reperfusion injury by upregulating the expression of beclin-1.