Hydrogen: From a Biologically Inert Gas to a Unique Antioxidant

Hydrogen gas (H2), a colorless, tasteless, odorless, non-irritating and highly flammable diatomic gas, has been used in medical applications to prevent decomposition sickness in deep divers. For a long time, H2 was thought to be a “biologically inert gas” which could not react with biomolecules under normal pressure. In 2007, Ohsawa et al. first reported that inhalation of H2 markedly suppressed brain injury induced by ischemia-reperfusion, which made the antioxidant properties of H2 drew wide attention (Ohsawa et al., 2007). Soon afterwards H2 was found to be effective for many other diseases, including hepatic and cardiac hypoxia-ischemia injury, inflammation injury caused by small intestine transplantation, neonatal hypoxia–ischemia injury, and lung allograft, (Fukuda et al., 2007; Buchholz et al., 2008; Cai et al., 2008; Hayashida et al., 2008; Kawamura et al., 2011;). Besides, other ways to administrate H2, such as drinking H2-saturated water, intraperitoneal and intravenous injection of H2-saturated saline (first developed by our group), have also been proved to be effective to many disorders related with oxidative stress, such as cerebral hypoxia-ischemia injury, human typeII diabetes, nephrotoxicity induced by cisplatin, Parkinson’s disease and atherosclerosis in apolipoprotein (Cai et al., 2009; Chen et al., 2009; Mao et al., 2009; Sun et al., 2009; Zheng et al., 2009; Oharazawa et al., 2010). Up to now, H2 has been proved to be effective to various disease models. Considering the unique antioxidant properties of H2, we believe it is important to review the medical researches of this novel antioxidant in this chapter. The aim of this chapter is to summarize research findings and mechanisms concerning the therapeutic potential of H2.