Protective effects of quercetin against myocardial ischemia/reperfusion injury in rats

The present study was to investigate the effects of quercetin on myocardial is chemia/reperfusion (MI/R) injury and investigated the underlying mechanisms. The expression of tumor necrosis factor alpha (TNF-alpha), interleukin- 6 (IL-6), lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and superoxidase dismutase (SOD) was evaluated by enzyme-linked immunosorbent assay (ELISA). Infarct size was measured by Evans blue/TTC double staining. Pathological changes of heart tissues were observed by HE staining. Levels of nuclear factor-kB (NF-kB) p65, PI3K, Akt, were determined by Western blotting. Pretreatment with quercetin significantly augmented rat cardiac function, as evidenced by increased left ventricular ejection fraction (LVEF) and +/- dP/dt. Quercetin reduced myocardial infarct size, markedly decreased LDH, CK, CK-MB, AST and MDA levels, and increased SOD, GSH-Px, CAT in the MI/R group. The protein levels of NF-kB p65 and Bax-2 were significantly decreased, while the protein levels of PI3K, Akt and Bcl-2 were significantly increased in a dose-dependent manner compared to the model group, respectively. Together, these data demonstrate that quercetin might protect myocardial ischemia via regulating PI3K/Akt/NF-kB p65 signaling.