Toxicity of lithium on isolated heart mitochondria and cardiomyocyte: A justification for its cardiotoxic adverse effect.

Mitochondria play an important role in myocardial tissue homeostasis; therefore, deterioration in mitochondrial function will eventually lead to cardiomyocyte and endothelial cell death and consequently cardiovascular dysfunction. Lithium (Li(+) ) is an effective drug for bipolar disorder with known cardiotoxic side effects. This study was designed to investigate the effects of Li(+) on mitochondria and cardiomyocytes isolated from the heart of Wistar rat. Results revealed that Li(+) induced a concentration- and time-dependent rise in mitochondrial ROS formation, inhibition of respiratory complexes (II), mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release in rat heart mitochondria and also induced Caspase 3 activation through mitochondrial pathway, decline of ATP and lipid peroxidation in rat cardiomyocytes. These results indicate that the cardiotoxic effects of Li(+) were initiated from mitochondrial dysfunction and oxidative stress, which finally ends in cytochrome c release and cell death signaling heart cardiomyocytes.