Protective Effects of Organic Acid-rich Fraction of CRATAEGI FRUCTUS PostConditioning on Myocardial Ischemia-Reperfusion Injury through PI3K/AKT and MAPK Signaling Pathways
Protective Effects of Organic Acid-rich Fraction of CRATAEGI FRUCTUS PostConditioning on Myocardial Ischemia-Reperfusion Injury through PI3K/AKT and MAPK Signaling Pathways
Objective:To investigate the mechanism of protective effects of organic acid-rich fraction of CRATAEGI FRUCTUS(OACP)against myocardial ischemia-reperfusion(I/R)injury by postconditioning.Methods:Hearts of Sprague-Dawley rats were perfused on Langendorff'apparatus and cardiac dynamic changes were recorded.Different concentrations of OACP were given in the perfusion solution from the reper-fusion stage.Myocardial infarct size was evaluated by TTC staining.Cell viability was measured through CellTiter 96 ® AQueous solution cell proliferation assay.H2O2-induced apoptosis was measured by flow cytometer.LDH release,intracellular MDA production,and antioxidant enzymes(SOD and GSH-Px)were determined by the corresponding kits.Caspase-3 and caspase-9 activity were measured by the assay kits.Expression levels of apoptosis-related proteins(Bax and Bcl-2),p-Akt,p-ERK,p-JNK and p-p38 were analyzed by Western blot.Results:Compared with control group,left ventricular diastolic pressure(LVDP)was significantly decreased in model group,myocardial infarct size was increased,and cell viability was significantly reduced(P＜0.01).LDH release and intracellular MDA level was significantly increased(P＜0.01).The activities of SOD and GSH-Px were significantly decreased(P＜0.01),while the activities of caspase-3 and caspase-9 were significantly increased(P＜0.01).The expressions of Bax was up regulated,while the expression of Bcl-2 was significantly decreased(P＜0.01).Akt and ERK phosphorylation was inhibited,while JNK and p38 phosphorylation was activated(P＜0.05 or P＜0.01).Compared with model group,OACP at 100 µg/mL markedly improved LVDP(P＜0.01),and decreased the infarct size(P＜0.01).OACP at 100 μg/mL significantly increased myocardial cell survival rate It markedly reduced LDH leakage and MDA production,and enhanced the ac-tivity of SOD and GSH-Px in H2O2-induced cardiomyocyte injury(P＜0.05 or P＜0.01).OACP significantly inhibited cardiomyocyte apopto-sis and the activity of caspase-3 and caspase-9.It down regulated the protein expressions of Bax and Bcl-2(P＜0.05 or P＜0.01).OACP up regulated the protein expressions of p-Akt and p-ERK(P＜0.05),while down regulated the protein expressions of p-JNK and p-p38(P＜0.01).The PI3K-specific inhibitor LY294002,JNK and p38-specific agonist Anisomycin,and the ERK-specific inhibitor PD98059 blocked the effect of OACP on cell viability and activity of caspase-3 induced by H2O2(P＜0.05 or P＜0.01).Conclusion:Effect of OACP against myocardial I/R injury may be related to enhancing antioxidant enzymes and suppressing apoptosis by postconditioning through PI3K/Akt and MAPK signaling pathways.
维普
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