BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the mechanism by which oxidative stress induced by chronic intermittent hypoxia (IH) causes myocardial damage in obstructive sleep apnoea syndrome. METHODS: A total of 160 Wistar rats were divided into five experimental groups and subjected to chronic IH with different concentrations of oxygen (5%, 7.5%, 10% IH groups; 10% continuous oxygen and normoxia control groups). Eight rats from each group were sacrificed at the 2-, 4-, 6- and 8-week time points. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) levels and total anti-oxidant capability (T-AOC) were measured in supernatants of heart homogenates. Expression of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, p22(phox) and NOX2, and thioredoxin-2 (Trx-2) genes were determined by measuring messenger RNA (mRNA) levels by real-time polymerase chain reaction. RESULTS: Compared with the control groups, MDA levels increased over time in the IH groups, whereas T-AOC and SOD activity decreased over time. MDA, T-AOC and SOD activity peaked at 6 weeks into the IH treatment. The 5% IH group showed significantly higher expression of p22(phox) and thioredoxin-2 mRNA, as compared with the other IH groups, as well as the control groups. CONCLUSIONS: The severity of oxidative stress induced by chronic IH in myocardial tissue was significantly correlated with the degree of IH. NADPH oxidase and Trx-2 are important mediators of oxidative stress induced by IH.
BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the mechanism by which oxidative stress induced by chronic intermittent hypoxia (IH) causes myocardial damage in obstructive sleep apnoea syndrome. METHODS: A total of 160 Wistar rats were divided into five experimental groups and subjected to chronic IH with different concentrations of oxygen (5%, 7.5%, 10% IH groups; 10% continuous oxygen and normoxia control groups). Eight rats from each group were sacrificed at the 2-, 4-, 6- and 8-week time points. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) levels and total anti-oxidant capability (T-AOC) were measured in supernatants of heart homogenates. Expression of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, p22(phox) and NOX2, and thioredoxin-2 (Trx-2) genes were determined by measuring messenger RNA (mRNA) levels by real-time polymerase chain reaction. RESULTS: Compared with the control groups, MDA levels increased over time in the IH groups, whereas T-AOC and SOD activity decreased over time. MDA, T-AOC and SOD activity peaked at 6 weeks into the IH treatment. The 5% IH group showed significantly higher expression of p22(phox) and thioredoxin-2 mRNA, as compared with the other IH groups, as well as the control groups. CONCLUSIONS: The severity of oxidative stress induced by chronic IH in myocardial tissue was significantly correlated with the degree of IH. NADPH oxidase and Trx-2 are important mediators of oxidative stress induced by IH.
Authors: Sherry E Adesina; Brandy E Wade; Kaiser M Bijli; Bum-Yong Kang; Clintoria R Williams; Jing Ma; Young-Mi Go; C Michael Hart; Roy L Sutliff Journal: Am J Physiol Lung Cell Mol Physiol Date: 2017-01-27 Impact factor: 5.464
Authors: Klara Hahnova; Iveta Brabcova; Jan Neckar; Romana Weissova; Anna Svatonova; Olga Novakova; Jitka Zurmanova; Martin Kalous; Jan Silhavy; Michal Pravenec; Frantisek Kolar; Jiri Novotny Journal: J Physiol Sci Date: 2017-05-31 Impact factor: 2.781
Authors: Hugo L Paz Y Mar; Stanley L Hazen; Russell P Tracy; Kingman P Strohl; Dennis Auckley; James Bena; Lu Wang; Harneet K Walia; Sanjay R Patel; Reena Mehra Journal: Chest Date: 2016-03-18 Impact factor: 9.410
Authors: Robert Williams; Paul Lemaire; Philip Lewis; Fiona B McDonald; Eric Lucking; Sean Hogan; David Sheehan; Vincent Healy; Ken D O'Halloran Journal: Front Physiol Date: 2015-01-30 Impact factor: 4.566