Icariin attenuated oxidative stress induced-cardiac apoptosis by mitochondria protection and ERK activation.

Our previous study showed that Icariin (ICA) has anti-cardiac hypertrophy effect in rats with an unknown mechanism. In the present study, we aimed to clarify the cardiac protective effect and mechanism of ICA in vitro. H9C2 cardiac myocytes were incubated with H2O2 to build up the oxidative stress injury model. The results showed that pre-treatment of ICA protected cells against the toxicity induced by H2O2. H2O2 treatment significantly reduced H2O2-induced apoptosis, evidenced by lower Annexin V/PI stained cells and less PARP and caspase-3/9 activation. Mitochondria membrane potential (MMP) dissipation occurred following the exposure of H2O2, which could be prevented by ICA treatment. Moreover, Ca2+ homeostasis was preserved by ICA and ROS generation was significantly suppressed by ICA incubation. Interestingly, ICA treatment increased the phosphorylation of upstream ERK mitogen-activated protein kinase (MAPK) while ERK inhibitor U1026 could reverse the protective effect of ICA. Overall, ICA seems to protect the cardiac cells from oxidative stress injury through ROS scavenge and stimulation of ERK pathway which may explain its effects in vivo.