2026-05-13T20:46:46Z https://www.peertechzpublications.org/oai-pmh

oai:www.peertechzpublications.org:10.17352/aprc.000022 2017-05-19 PTZ.APRC:VOL3

Hypoxia/Reoxygenation modulates Oxidative Stress Level and Antioxidative Potential in Lung Mitochondria: Possible participation of P53 and NF-KB Target Proteins Olga GoncharIrina Mankovska<p><strong>Background&nbsp; and&nbsp; objective:</strong> Hypoxia/reoxygenation&nbsp; (H/R)&nbsp; is&nbsp; a&nbsp; key&nbsp; factor&nbsp; in&nbsp; the&nbsp; pathogenesis of the most lung diseases&nbsp; where exсessive&nbsp; ROS&nbsp; production and&nbsp; prooxidant/antioxidant&nbsp; imbalance greatly contribute to disease progression. We have used severe hypoxia in sessions of repeated H/R of different duration as&nbsp; a model of lung&nbsp; pathologic&nbsp; states&nbsp; to&nbsp; investigate&nbsp; mitochondrial&nbsp; oxidative&nbsp; stress&nbsp; intensity, protein&nbsp;&nbsp; expression/activity of antioxidant enzymes manganese-superoxide&nbsp;&nbsp; dismutase (MnSOD), glutathione&nbsp; peroxidase&nbsp; (GPx),&nbsp; and&nbsp; antiapoptotic&nbsp; Bcl-2&nbsp; as&nbsp; well&nbsp; as&nbsp; protein&nbsp; expression&nbsp; of&nbsp; their&nbsp; upstream regulators: p53 and nuclear factor- kappa B (NF-kB).</p><p><strong>Methods: </strong>A total 86 rats were divided into five experimental groups and subjected to H/R [5 cycles of&nbsp; 10&nbsp; min&nbsp; hypoxia&nbsp; (5.5&nbsp; %&nbsp; O2&nbsp; in&nbsp; N2)&nbsp; alternated&nbsp; with&nbsp; 10&nbsp; min&nbsp; normoxia,&nbsp; daily].&nbsp; Eight&nbsp; rats&nbsp; from&nbsp; each&nbsp; group were sacrificed&nbsp; on&nbsp; 1st&nbsp; -,&nbsp; 3rd&nbsp; -&nbsp; day,&nbsp; 1st&nbsp; and&nbsp; 2nd&nbsp; -&nbsp; week&nbsp; time&nbsp; points.&nbsp; Oxidative&nbsp; stress&nbsp; biomarkers&nbsp; (ROS formation,&nbsp; lipid&nbsp; peroxidation,&nbsp; H2O2&nbsp; production,&nbsp; GSH/GSSG&nbsp; ratio,&nbsp; and&nbsp; mitochondrial&nbsp; aconitase&nbsp; activity as marker of compartment-specific superoxide anion production), indices of antioxidant status (MnSOD,GPx,&nbsp; glutathione&nbsp; –S-transpherase&nbsp; activities,&nbsp; and&nbsp; reduced&nbsp; glutathione&nbsp; level)&nbsp; were&nbsp; measured&nbsp; in&nbsp; lung mitochondria.&nbsp; Western&nbsp; blot&nbsp; was&nbsp; used&nbsp; to&nbsp; detect&nbsp; the&nbsp; protein&nbsp; levels&nbsp; of&nbsp; p53,&nbsp; Bcl-2,&nbsp; MnSOD,&nbsp; and&nbsp; GPx&nbsp; in mitochondria as well as the phosphorylated NF-kB p65 in the nucleus of lung cells. Expression of mRNA MnSOD was determined by real-time polymerase chain reaction.</p><p><strong>Results: </strong>The short- (1-3 days) and long-term (1-2 wk) H/R differentially affects the oxidative stress level,&nbsp; p53&nbsp; protein&nbsp; expression&nbsp; and&nbsp; its&nbsp; subcellular&nbsp; distribution&nbsp; as well as antioxidant&nbsp; capacity&nbsp; in&nbsp; lung mitochondria.The&nbsp; long-term&nbsp; H/R&nbsp; caused&nbsp; mitochondrial&nbsp; p53 protein&nbsp; translocation, a decrease in Bcl-2 protein&nbsp; content, and&nbsp; a&nbsp; significant&nbsp; increase in nuclear&nbsp; accumulation&nbsp; of&nbsp; the&nbsp; phosphorylated&nbsp; NF κB p65 protein. We observed&nbsp; an&nbsp; increase&nbsp; in&nbsp; GPx&nbsp; protein&nbsp; content/activity, in parallel&nbsp; with&nbsp; decrease&nbsp; in&nbsp; MnSOD protein&nbsp; level&nbsp; and&nbsp; activity.&nbsp; In&nbsp; the dynamics of&nbsp; MnSOD&nbsp; gene expression&nbsp; we&nbsp; found&nbsp; a&nbsp; phase&nbsp; time&nbsp; point dependence.</p><p><strong>Conclusions:</strong>&nbsp; Long&nbsp; lasting&nbsp; H/R&nbsp; leads&nbsp; to&nbsp; mitochondrial&nbsp; prooxidant/antioxidant&nbsp; disbalance&nbsp; that resulted&nbsp; in&nbsp; redox&nbsp; alteration&nbsp; as&nbsp; consequence&nbsp; of&nbsp; oxidative&nbsp; stress&nbsp; propagation&nbsp; and&nbsp; apoptotic&nbsp; cascade activation. A close correlation between mitochondrial p53 Protein level and protein expression/activities of&nbsp; its&nbsp; targets&nbsp; MnSOD&nbsp; and&nbsp; GPx&nbsp; suggest&nbsp; participation&nbsp; of&nbsp; p53&nbsp; in&nbsp; regulation&nbsp; of&nbsp; H/R-induced&nbsp; mitochondrial oxidative stress level.</p> Archives of Pulmonology and Respiratory Care - Peertechz Publications 2017-05-19 Research Article https://doi.org/10.17352/aprc.000022 en Copyright © Olga Gonchar et al.