Oxidative stress, antioxidant defenses and nitric oxide production following hyperoxic exposures

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2013-04-01

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Abstract

Little data exist on the dose-response relationship between the partial pressure of inspired oxygen (PiO2) and the cellular oxidative stress response in humans. The objective of this study was to determine the effects of PiO2 on lipid peroxidation, antioxidant enzyme activity and nitric oxide (NO) production. Twelve healthy male divers breathed 100% O2 in a hyperbaric chamber for two hours at 1 (101 kPa), 1.5 (152 kPa) and 2 (203 kPa) atmospheres absolute (atm abs). Venous blood was collected pre-, within 15 minutes post-, one and two hours post-hyperoxic exposures to determine changes in plasma and erythrocyte lipid peroxidation (thiobarbituric acid reactive substances-TBARS), antioxidant enzyme activity (superoxide dismutase-SOD), catalase-CAT, glutathione peroxidase-GPx), and plasma NO production (L-arginine [L-Arg], asymmetric dimethylarginine-ADMA, and nitrites). There were minor changes in TBARS and mixed responses in plasma and erythrocyte CAT and GPx activity. Plasma L-Arg increased following 1 and 1.5 atm abs exposures, yet ADMA and nitrites were unchanged. Only erythrocyte CAT and plasma GPx activity, and plasma L-Arg/ADMA demonstrated a significant PiO2 dose-dependent relationship. Two-hour hyperoxic exposures at 1-2 atm abs of O2 results in mixed oxidant-antioxidant responses and unaltered NO production. Moreover, there does not appear to be a strong systemic dose-dependent oxidative stress response at these hyperoxic exposures

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Scholars@Duke

Gasier

Heath Gasier

Associate Professor in Anesthesiology

Dr. Gasier is a physiologist and nutritionist. His research is focused on understanding how breathing altered PO2 impacts cell physiology in the lung, brain, and skeletal muscle. Emphasis is placed on mitochondrial quality control (dynamics, mitophagy, and biogenesis) and bioenergetics. He uses in vivo and in vitro models, and employs an array of methods (e.g., confocal and electron microscopy, Seahorse respiration, immunoblotting, RT-qPCR, ELISA’s, isotope tracers, and 10X genomics) for hypothesis testing. The goal of his research is to improve the operational capacity of divers and safety of hyperoxia in hyperbaric and critical care medicine. Dr. Gasier believes in a hands-on mentoring approach and individualized training plans based on mentee’s aspirations. He is committed to lifetime learning and contributing to knowledge advancement. 


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