Hydrogen as a new class of radioprotective agent.

It is well known that most of the ionizing radiation-induced damage is caused by hydroxyl radicals (·OH) follows radiolysis of H2O. Molecular hydrogen (H2) has antioxidant activities by selectively reducing ·OH and peroxynitrite(ONOO-). We firstly hypothesized and demonstrated the radioprotective effect of H2 in vitro and in vivo, which was also repeated on different experimental animal models by different departments. A randomized, placebo-controlled study showed that consumption of hydrogen-rich water reduces the biological reaction to radiation-induced oxidative stress without compromising anti-tumor effects. These encouraging results suggested that H2 represents a potentially novel preventative strategy for radiation-induced oxidative injuries. H2 is explosive. Therefore, administration of hydrogen-rich solution (physiological saline/pure water/other solutions saturated with H2) may be more practical in daily life and more suitable for daily consumption. This review focuses on major scientific and clinical advances of hydrogen-rich solution/H2 as a new class of radioprotective agent.