Bolgova T. Structural, dynamic and functional features of lung and heart mitochondria under different modes of intermittent hypoxic training

There was studied morhpo-functional peculiarities of lung and heart mitochondria (M) of rats after two intermittent hypoxic training (IHT) regimen with using of acute hypoxia (AH) as the testing influence for the exposure of mechanisms which are responsible for mitochondrial adaptation to hypoxia. The obtained results discovered that IHT led to organospesific morpho-functional changes in lung and heart M of constructive (adaptive) and destructive character. IHT with moderate hypoxic component (12% 02 in N2) results in advantage of adaptive changes in lung and heart M which where directed to the improvement of terms and mechanisms of oxygen consumption. These changes expressed in: the rise of M quantity and the appearance of young organelles; an increase of area of mitochondrial membranes; the cristae rebuilding in more power capacious form; M migration toward zones of hypoxic damage; dynamic changes directed to reparation of damaged M; an increase of phosphorylation efficiency and coupling of breathing with phosphorylation under NAD- dependent substrates oxidation. IHT with more severe hypoxic component (7% 02 in N2) led to the expressed destructive changes of M in both organs: partial or complete vacuolization of organelles; the appearance of mielinizated M; dilution of internal and, here and there, break of external mitochondrial membranes; an increase in heterogeneity of mitochondrial population; advantage of mitochondrial fission above the processes of fusion. The adaptive changes of M at this mode of IHT consisted in the rise of general area of mitochondrial membranes; migration of subsarcolemmal M toward the sarcolemma invagination and intramiofibrilar M - to the perinuclear space. It allowed M of both organs to provide their power demands at the level of control values. Increased levels of mRNA NRF-1 expression on a background of both applied modes of IHT testified for intensification of mitochondrial biogenesis, more shown in heart. Wery high expression levels of this gene where observed after IHT with more severe hypoxic component and took place on a background of the expressed destructive changes in M. AH which was used for the estimation of efficiency of IHT showed, that the leading mechanisms provided such efficiency IHT are: increased area of M membranes; change of dynamic processes toward fusion of these membranes; high level of the breathing with phosphorylation coupling; the rise of mitochondrial biogenesis intensity.