Mechanisms of cinnamic aldehyde against myocardial ischemia/hypoxia injury in vivo and in vitro: Involvement of regulating PI3K/AKT signaling pathway

To investigate the protection of cinnamic aldehyde (CA) against myocardial ischemia/hypoxia (I/H) injury and its potential mechanisms in vivo and in vitro. Mice were pretreated with CA for 7 days, and then isoproterenol (85 mg/kg) was administered for 2 consecutive days to assess its cardioprotection. Furthermore, an in vitro myocardial I/H model was established by administering CoCl2 (600 μM) to H9c2 cells for 24 h. H9c2 cells were pretreated with CA for 12 h to assess its protection. We observed that CA improved electrocardiogram and histopathological changes and decreased creatine kinase and lactate dehydrogenase activities and oxidative stress levels. The TUNEL results showed that CA reduced the degree of apoptosis. Furthermore, CA could lead to a down-regulation of the Caspase-3 and Bax protein expressions, but an up-regulation of the Bcl-2 protein expressions. Importantly, CA increased p-PI3K and p-AKT protein expressions, indicating the activation of the PI3K/AKT signaling pathway. Moreover, treatment with CA improved the cell viability rate and mitochondrial membrane potential while markedly decreasing apoptosis and oxidative stress levels in vitro. Our results suggested that CA exerts cardioprotection on myocardial I/H injury, which possibly occurred in connection with inhibition of oxidative stress and apoptosis via activation of the PI3K/AKT signaling pathway.