the effects of low-pressure hyperbaric oxygen (HBO) treatment before and after maximal exercise on lactate concentration and heart rate and antioxidant capacity.
https://www.e-jer.org/journal/view.php?number=2013600610
Reactive oxygen species (ROS)
Reactive oxygen species (ROS) are highly reactive chemical molecules formed due to the electron acceptability of O2. Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen,[3] and alpha-oxygen.
The reduction of molecular oxygen (O2) produces superoxide (•O−
2), which is the precursor of most other reactive oxygen species:[4]
- O2 + e− → •O−
2 - 活性氧類（英語：Reactive oxygen species，ROS），是生物有氧代謝過程中的一種副產品，包括氧離子、過氧化物和含氧自由基等。[1]這些粒子相當微小，由於存在未配對的自由電子，而十分活躍。過高的活性氧水平會對細胞和基因結構造成損壞。活性氧，為含氧的，具有化學活性的分子，包括氧離子（oxygen ion）及過氧化氫（peroxide）。因為核外的未配對電子的存在，具有很強的化學反應活性。ROS是正常氧代謝的副產物，並且在細胞信號傳導，和保持機體恒常性起很大作用。然而，在時間以及外界環境影響下（例，暴露於紫外線(UV exposure)或熱源(heat exposure)下等），ROS的量會急劇增多。引起這種改變的原因有可能是由於明顯的細胞結構的損壞。這種顯現，被稱為氧化應激。ROS也可能由外界的因素生成，如致電離輻射。
- 通常，細胞都會通過酶（如，過氧化歧化酶superoxide dismutase等）的作用來減少ROS對細胞的損傷作用。某些小分子，如維生素C 維生素E，尿酸及穀胱甘肽也作為細胞抗氧化物質發揮著重要作用。與之相對，細胞外的抗氧化物質的作用小的多，在血漿中的最重要的抗氧化物質為 尿酸uric acid。
- -----------
- Hyperbaric oxygen treatment induces antioxidant gene expression
- https://pubmed.ncbi.nlm.nih.gov/20536847/
-
Antioxidant status in humans after exposure to hyperbaric oxygen
Abstract
Hyperbaric oxygen (HBO) treatment (i.e., exposure to 100% oxygen at a pressure of 2.5 atmosphere absolute (ATA) for a total of 3×20 min periods) of human subjects induced DNA damage in the alkaline comet assay with leukocytes and protected against the DNA damaging effects of subsequent in vivo HBO exposures. Furthermore, blood taken 24 h after the first HBO was well protected against the in vitro induction of genotoxic effects by hydrogen peroxide. To investigate the mechanisms which led to this apparent adaptive response, we determined the antioxidant status of blood from subjects before and after HBO. We did not find differences in the plasma concentrations of the antioxidant vitamins A, C and E after HBO treatment. HBO had also no effect on the `antioxidant power' of the plasma as measured with the FRAP-assay or on the concentration of reduced glutathione determined in the plasma or in lymphocytes. Red cell concentrate activities of superoxide dismutase, catalase, glutathione peroxidase were not influenced by HBO. In contrast, synthesis of the heat shock protein HSP70 which has been implicated to play an important role in cellular protection against oxidative stress, was significantly induced in lymphocytes after a single HBO treatment. To investigate whether intake of antioxidants may protect against HBO-induced DNA damage, we supplemented subjects with vitamin E (800 mg for 7 days) or with N-acetylcysteine (400 mg, 1 h before the HBO treatment). However, these supplementations did not influence the induction of DNA damage by HBO.
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https://www.sciencedirect.com/science/article/abs/pii/S1383574299000344
