Reduced mitochondrial response sensitivity is involved in the anti-apoptotic effect of dexmedetomidine pretreatment in cardiomyocytes

Dexmedetomidine is a commonly used 2-adrenoceptor agonist, which affects various organs, including providing beneficial effects on the heart. However, the mechanism underlying the cardiac benefit remains to be fully elucidated. In the present study, it was demonstrated that dexmedetomidine pretreatment on primary cultured rat cardiomyocytes protected against reactive oxygen species (ROS)-induced apoptosis. In terms of the potential mechanism, it was demonstrated that dexmedetomidine inhibited mitochondrial biogenesis and mitochondrial respiratory complexes, but with increased coupling efficiency. However, dexmedetomidine upregulated mitochondrial membrane potential ((m)) and resisted against the loss of (m) induced by carbonilcyanide p-triflouromethoxyphenylhydrazone. Due to the importance of mitochondria affecting ROS, the present study investigated the dexmedetomidine-suppressed mitochondrial response to H2O2 stimulation, which was explained by suppressed ROS levels and the suppression of the increased oxygen consumption rate. Results demonstrated for the first time, to the best of our knowledge, a novel protective mechanism for dexmedetomidine on cardiomyocytes through the attenuated response of mitochondria towards H2O2, which had a protective effect against ROS-induced apoptosis.