Effects of PI3K/Akt-eNOS signaling pathway on total flavones in Clematis filamentosa post-conditioning alleviated of myocardial ischemia-reperfusion injury in rats / 中国中药杂志

ABSTRACT

The aim of this paper was to study the effect of total flavones of Clematis filamentosa Dunn(TFCD) post-conditioning against myocardial ischemia-reperfusion injury (MIRI) and the role of PI3K/Akt-eNOS signaling pathway. Forty male SD rats were divided randomly into five groups Sham group, model group (I/R), TFCD post-conditioning group (TFCD), TFCD post-condition-ing+LY294002 (a PI3K/Akt signaling pathway inhibitor) group (TFCD+LY), and LY294002 group (LY). At the end of reperfusion, hemodynamic parameters were recorded, morphology changes of myocardial tissue were evaluated by using HE staining, and myocardial infarct size were observed, blood samples were obtained to determine plasma activation of lactate dehydrogenase (LDH), creatine kinase (CK) nitric oxide (NO), endothelial nitric oxide synthase (eNOS), superoxide dismutase (SOD), maleic dialdehyde (MDA) and glutathione peroxidase (GSH-Px). The expressions of Akt, p-Akt, eNOS and p-eNOS proteins were assessed by using Western blot, and eNOS and inducible nitric oxide synthase (iNOS) mRNA was measured by RT-PCR. The results showed that, compared with the model group, TFCD post-conditioning remarkably improved hemodynamics function and myocardial structure, reduced myocardial infarct size and enhanced the contents of NO, eNOS, SOD and GSH-Px, and decreased the contents of LDH, CK and MDA, increased the levels of phosphorylation of Akt and eNOS protein expression, eNOS and iNOS mRNA expression significantly(P＜0.05 or P＜0.01). These effects were inhibited by LY294002, a blocker of PI3K/Akt signaling pathway. The above experiments indicated that TFCD post-conditioning could significantly reduce MIRI in rats, the mechanism of which may be associated with increasing antioxidation, scavenging oxygen free radicals, regulating NO generation and activating PI3K/Akt-eNOS signaling pathway.