Resistance of myocardial mitochondria in ischemia-reperfusion injury of the heart in rats adapted to chronic hypoxia

The parameters of respiration, the value of the transmembrane potential, and Са2+-binding capacity of the mitochondria isolated from the Langendorff-perfused hearts of rats adapted to chronic continuous normobaric hypoxia were analyzed. Modeling of ischemia and reperfusion in intact and adapted animals resulted in reduced Са2+-binding capacity of mitochondria, indicating an increase in the sensitivity of mitochondrial permeability transition pore (MPT-pore) to calcium ions. At the same time, reduction in transmembrane potential, reduction in ADP/O ratio (the ratio of added ADP to oxygen consumption in State 3), and inhibition of mitochondrial state 3 respiration were observed. Along with that, the study demonstrated that the adaptation of animals to chronic hypoxia promotes the resistance of myocardial mitochondria to the negative effects of ischemia and reperfusion.