Tilianin Post-Conditioning Attenuates Myocardial Ischemia/Reperfusion Injury via Mitochondrial Protection and Inhibition of Apoptosis

BACKGROUND: The aim of this study was to investigate the role of tilianin in modulating mitochondrial functions and mitochondria-mediated apoptosis during cardio-protection. MATERIAL/METHODS: Myocardial ischemia/reperfusion (I/R) injury was induced by 30 minutes coronary occlusion followed by two hours reperfusion in Sprague-Dawley rats. To investigate the cardio-protective effects of tilianin, apoptosis was evaluated by TUNEL. Mitochondrial ultrastructure and function were assessed by transmission electron microscopy, dynamics of mitochondrial permeability transition pore (mPTP) opening and ATP production in the myocardium; Ca(2+) content and reactive oxygen species (ROS) were measured to evaluated the level of damage factors in the mitochondria. The related apoptotic proteins were analyzed through immunoblot. RESULTS: Pretreatment with tilianin significantly reduced apoptosis after I/R injury in rats (p<0.05). In addition, tilianin could alleviate mitochondrial damage, markedly inhibited mPTP opening and improved ATP production (p<0.05). There was also a significant reduction for content of Ca(2+) and ROS in the mitochondria (p<0.01). Apoptosis protein analysis found that treatment with tilianin led to the downregulation of apoptosis-inducing factor (AIF) (p<0.01), and suppressed the leakage of cytochrome c and activation of caspase-3 (p<0.05). CONCLUSIONS: This study showed that tilianin can alleviate apoptosis of cardiomyocytes and protect myocardium, possibly via the protection of mitochondria and repression of mitochondrial apoptotic pathways. Mechanistically, inhibition of Ca(2+) overload, mPTP opening, and ROS production in mitochondria may explain the observed tilianin-mediated treatment effects.