In recent years, experimental evidences have documented that without influencing other less potent ROS, important in intracellular signaling, molecular hydrogen possesses the ability to selectively neutralize ONOO
- and •OH, the most cytotoxic ROS, which can damage cellular macromolecules aggressively and indiscriminately. Thus, hydrogen can protect cells from oxidative stress injuries [
10]. Therapeutic effects of hydrogen gas and hydrogen-rich saline have been experimentally confirmed in a number of studies, including hypoxia [
11,
12], ischemia-reperfusion injuries in various tissues and organs [
13‐
18], and other injuries related to oxidative stress. Especially in brain ischemia, our previous research has demonstrated that hydrogen administration after hypoxia appeared to provide brain protection via inhibition of neuronal apoptosis in neonatal hypoxia-ischemia rat model [
19]. Another study reported that 2.1% hydrogen-supplemented room air ventilation would preserve cerebrovascular reactivity (CR) and brain morphology after asphyxia/reventilation (A/R) in newborn pigs [
20]. For transient cerebral ischemia, hydrogen also showed significant protective effects [
21]. Several studies have demonstrated the neuroprotective effects of molecular hydrogen. Interestingly enough, even for some chronic neurodegenerative diseases, like the Alzheimer's disease [
22] and Parkinson disease [
23,
24], hydrogen showed certain protective effects.
As a novel antioxidant, hydrogen possesses a number of advantages. (1) Due to its high permeability, hydrogen can easily penetrate biomembranes and diffuse into the cytosol, mitochondria and nucleus. (2) It is nontoxic to the organisms, which has been proven by hyperbaric diving study for decades. (3) Due to its selectivity as an antioxidant, hydrogen has less impact on other less active but very important ROS within the cells.