Fisetin ameliorates ischemia re-oxygenation injury in H9c2 cardiomyocytes via targeting the PI3K signalling pathway

Abstract

Background: The rat myocardium consists of different cell types of which cardiomyocytes account for 70% of the total surface area. The extent of ischemia reoxygenation injury (IRI) experienced by each cell type of the heart varies. Fisetin, a natural flavonoid is reported to ameliorate reperfusion injury in rat heart but the direct cardiotoxic effect of fisetin and its impact on IRI is yet to be evaluated in rat cardiomyocytes. Purpose: To evaluate the impact of IRI in cardiomyocytes and to study the underlying mechanism. Methods: In the present study, to mimic myocardial ischemia reperfusion, ischemia re-oxygenation (IR) model was adopted in H9c2 (2-1) cells. Fisetin (20 µM) was administrated to the cells: before ischemia, during ischemia and after ischemia via the respective incubation medium. Results: The results showed that fisetin pre-treatment renders significant improvement in cell viability in IR simulated cells when compared with other two modes of administration. In addition, fisetin significantly reduced oxidative stress and improved mitochondrial ETC enzyme activity. However, the fisetin-mediated protection was absent in presence of rotenone. Fisetin pre-treatment enhanced the activation of PI3K pathway in IR simulated cells, which was further reconfirmed using Wortmannin, a PI3K inhibitor, where the protective effect of fisetin was negated. Conclusion: Fisetin pre-treatment increases cell viability via reducing oxidative stress and preserving the functional activity of mitochondria in H9c2 cells. The underlying mechanism of action is associated with the activation of the PI3K signalling pathway.

Keywords

• Fisetin
• Ischemia reperfusion injury
• Ischemia re-oxygenation
• Cardiomyocytes
• Mitochondria
• PI3K pathway