Isosteviol Protects H9c2 Cells Against Hypoxia-reoxygenation by Activating ERK1/2

Aims: In the present study, we have investigated the cardioprotective properties of Isosteviol (STV) under conditions of hypoxia-reoxygenation and elucidated the underlying mechanism. Background: In our previous studies, we have determined that STV exhibits neuro- and cardio-protective properties. However, the mechanism underlying STV-induced cardioprotection has not yet been fully understood. Methods: All experiments were performed on rat heart embryonic H9c2 cell line. To induce hypoxia- reoxygenation, cells were exposed to 1% oxygen (in no glucose and no sodium pyruvate DMEM) following by reoxygenation (using fully supplemented MEM). Cells viability was tested by MTT assay, and protein levels were compared by Western blotting. Results: Treatment of heart embryonic H9c2 cells with STV (10 μM) significantly increased the survival of cells exposed to hypoxia-reoxygenation. STV (10 μM) activated ERK1/2 and DRP1 in hypoxia-reoxygenation, but did not have any effects on ERK1/2 or DRP1 in normoxia. STV (10 μM) did not regulate CAMKII, AKT or AMPK signaling pathways. Conclusion: Taken all together, our findings demonstrate that 1) STV protects H9c2 cells against hypoxia-reoxygenation and that 2) this effect is mediated via ERK1/2. The property of STV that selectively activates ERK1/2 in cells exposed to stress, but not in cells under non-stress conditions, makes this compound a promising candidate-drug for therapy against myocardial ischemia-reperfusion in clinical practice.