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Molecular hydrogen (H2) is an efficient antioxidant that diffuses rapidly across cell membranes, reduces reactive oxygen species (ROS), such as hydroxyl radicals and peroxynitrite, and suppresses oxidative stress-induced injury in several organs. ROS have been implicated in radiation-induced damage to lungs. Because prompt elimination of irradiation-induced ROS should protect lung tissue from damaging effects of irradiation, we investigated the possibility that H2 could serve as a radioprotector in the lung. Cells of the human lung epithelial cell line A549 received 10 Gy irradiation with or without H2 treatment via H2-rich PBS or medium. We studied the possible radioprotective effects of H2 by analyzing ROS and cell damage. Also, C57BL/6J female mice received 15 Gy irradiation to the thorax. Treatment groups inhaled 3% H2 gas and drank H2-enriched water. We evaluated acute and late-irradiation lung damage after H2 treatment. H2 reduced the amount of irradiation-induced ROS in A549 cells, as shown by electron spin resonance and fluorescent indicator signals. H2 also reduced cell damage, measured as levels of oxidative stress and apoptotic markers, and improved cell viability. Within 1 wk after whole thorax irradiation, immunohistochemistry and immunoblotting showed that H2 treatment reduced oxidative stress and apoptosis, measures of acute damage, in the lungs of mice. At 5 mo after irradiation, chest computed tomography, Ashcroft scores, and type III collagen deposition demonstrated that H2 treatment reduced lung fibrosis (late damage). This study thus demonstrated that H2 treatment is valuable for protection against irradiation lung damage with no known toxicity. [ABSTRACT FROM AUTHOR]

Acute oxidative stress induced by ischemia-reperfusion or inflammation causes serious damage to tissues, and persistent oxidative stress is accepted as one of the causes of many common diseases including cancer. We show here that hydrogen (H2) has potential as an antioxidant in preventive and therapeutic applications. We induced acute oxidative stress in cultured cells by three independent methods. H2 selectively reduced the hydroxyl radical, the most cytotoxic of reactive oxygen species (ROS), and effectively protected cells; however, H2 did not react with other ROS, which possess physiological roles. We used an acute rat model in which oxidative stress damage was induced in the brain by focal ischemia and reperfusion. The inhalation of H2 gas markedly suppressed brain injury by buffering the effects of oxidative stress. Thus H2 can be used as an effective antioxidant therapy; owing to its ability to rapidly diffuse across membranes, it can reach and react with cytotoxic ROS and thus protect against oxidative damage. [ABSTRACT FROM AUTHOR]

Inhalation of molecular hydrogen (H2) gas ameliorates oxidative stress-induced acute injuries in the brain. Consumption of water nearly saturated with H2 also prevents chronic neurodegenerative diseases including Parkinson’s disease in animal and clinical studies. However, the molecular mechanisms underlying the remarkable effect of a small amount of H2 remain unclear. Here, we investigated the effect of H2 on mitochondria in cultured human neuroblastoma SH-SY5Y cells. H2 increased the mitochondrial membrane potential and the cellular ATP level, which were accompanied by a decrease in the reduced glutathione level and an increase in the superoxide level. Pretreatment with H2 suppressed H2O2-induced cell death, whereas post-treatment did not. Increases in the expression of anti-oxidative enzymes underlying the Nrf2 pathway in H2-treated cells indicated that mild stress caused by H2 induced increased resistance to exacerbated oxidative stress. We propose that H2 functions both as a radical scavenger and a mitohormetic effector against oxidative stress in cells. [ABSTRACT FROM AUTHOR]

Hydrogen gas reduces ischemia and reperfusion injury (IRI) in the liver and other organs. However, the precise mechanism remains elusive. We investigated whether hydrogen gas ameliorated hepatic I/R injury after cold preservation. Rat liver was subjected to 48-h cold storage in University of Wisconsin solution. The graft was reperfused with oxygenated buffer with or without hydrogen at 37° for 90 min on an isolated perfusion apparatus, comprising the H2(+) and H2(−) groups, respectively. In the control group (CT), grafts were reperfused immediately without preservation. Graft function, injury, and circulatory status were assessed throughout the perfusion. Tissue samples at the end of perfusion were collected to determine histopathology, oxidative stress, and apoptosis. In the H2(−) group, IRI was indicated by a higher aspartate aminotransferase (AST), alanine aminotransferase (ALT) leakage, portal resistance, 8-hydroxy-2-deoxyguanosine-positive cell rate, apoptotic index, and endothelial endothelin-1 expression, together with reduced bile production, oxygen consumption, and GSH/GSSG ratio (vs. CT). In the H2(+) group, these harmful changes were significantly suppressed [vs. H2(−)]. Hydrogen gas reduced hepatic reperfusion injury after prolonged cold preservation via the maintenance of portal flow, by protecting mitochondrial function during the early phase of reperfusion, and via the suppression of oxidative stress and inflammatory cascades thereafter. [ABSTRACT FROM AUTHOR]

We have reported that hydrogen (H2) acts as an efficient antioxidant by gaseous rapid diffusion. When water saturated with hydrogen (hydrogen water) was placed into the stomach of a rat, hydrogen was detected at several μM level in blood. Because hydrogen gas is unsuitable for continuous consumption, we investigated using mice whether drinking hydrogen water ad libitum, instead of inhaling hydrogen gas, prevents cognitive impairment by reducing oxidative stress. Chronic physical restraint stress to mice enhanced levels of oxidative stress markers, malondialdehyde and 4-hydroxy-2-nonenal, in the brain, and impaired learning and memory, as judged by three different methods: passive avoidance learning, object recognition task, and the Morris water maze. Consumption of hydrogen water ad libitum throughout the whole period suppressed the increase in the oxidative stress markers and prevented cognitive impairment, as judged by all three methods, whereas hydrogen water did not improve cognitive ability when no stress was provided. Neural proliferation in the dentate gyrus of the hippocampus was suppressed by restraint stress, as observed by 5-bromo-2′-deoxyuridine incorporation and Ki-67 immunostaining, proliferation markers. The consumption of hydrogen water ameliorated the reduced proliferation although the mechanistic link between the hydrogen-dependent changes in neurogenesis and cognitive impairments remains unclear. Thus, continuous consumption of hydrogen water reduces oxidative stress in the brain, and prevents the stress-induced decline in learning and memory caused by chronic physical restraint. Hydrogen water may be applicable for preventive use in cognitive or other neuronal disorders.Neuropsychopharmacology (2009) 34, 501–508; doi:10.1038/npp.2008.95; published online 18 June 2008 [ABSTRACT FROM AUTHOR]

Abstract: We have recently showed that molecular hydrogen has great potential for selectively reducing cytotoxic reactive oxygen species, such as hydroxyl radicals, and that inhalation of hydrogen gas decreases cerebral infarction volume by reducing oxidative stress [I. Ohsawa, M. Ishikawa, K. Takahashi, M. Watanabe, K. Nishimaki, K. Yamagata, K.-I. Katsura, Y. Katayama, S. Asoh, S. Ohta, Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals, Nat. Med., 13 (2007) 688–694]. Here we show that the inhalation of hydrogen gas is applicable for hepatic injury caused by ischemia/reperfusion, using mice. The portal triad to the left lobe and the left middle lobe of the liver were completely occluded for 90min, followed by reperfusion for 180min. Inhalation of hydrogen gas (1–4%) during the last 190min suppressed hepatic cell death, and reduced levels of serum alanine aminotransferase and hepatic malondialdehyde. In contrast, helium gas showed no protective effect, suggesting that the protective effect by hydrogen gas is specific. Thus, we propose that inhalation of hydrogen gas is a widely applicable method to reduce oxidative stress. [Copyright &y& Elsevier]

Abstract: The major side-effect of treatment with α-glucosidase inhibitors, flatulence, occurs when undigested carbohydrates are fermented by colonic bacteria, resulting in gas formation. We propose that the cardiovascular benefits of α-glucosidase inhibitors are partly attributable to their ability to neutralise oxidative stress via increased production of H2 in the gastrointestinal tract. Acarbose, which is an α-glucosidase inhibitor, markedly increased H2 production, with a weaker effect on methane production. Our hypothesis is based on our recent discovery that H2 acts as a unique antioxidant, and that when inhaled or taken orally as H2-dissolved water it ameliorates ischaemia–reperfusion injury and atherosclerosis development. [Copyright &y& Elsevier]