Effect of Hydrogen Gas on the Survival Rate of Mice Following Global Cerebral Ischemia

Abstract

Global cerebral ischemia and reperfusion (I/R) often result in high mortality. Free radicals have been reported to play an important role in global cerebral I/R, and therefore, reduction of these might improve the outcome. Here, we investigated the effect of hydrogen gas (H2) (a strong free radical scavenger) on the survival rate of mice following global cerebral I/R. We further examined the histopathological outcome and also the brain water content (as a possible determinant of mortality). Male C57BL/6J mice were subjected to global cerebral I/R by means of 45-min bilateral common carotid artery occlusion (BCCAO). A total of 160 mice were divided into three groups: sham surgery (sham group), BCCAO without H2 (BCCAO group), and BCCAO treated with 1.3% H2 (BCCAO + H2 group). We observed that H2 treatment significantly (P = 0.0232) improved the 7-day survival rate of mice, from 8.3% (BCCAO group, n = 12) to 50% (BCCAO + H2 group, n = 10). Histopathological analysis revealed that H2 treatment significantly attenuated neuronal injury and autophagy in the hippocampal cornu ammonis 1 sector and also brain edema, after 24 h of reperfusion. The beneficial effects of H2 treatment on brain injury were associated with significantly lower levels of oxidative stress markers (8-hydroxy-2'-deoxyguanosine and malondialdehyde) in the brain tissue. Thus, we believe that H2 may be an effective treatment for global cerebral I/R.

Hydrogen does not exert neuroprotective effects or improve functional outcomes in rats after intracerebral hemorrhage

“…gas of 1.3% because this is the highest concentration that can be mixed and bottled under high pressure with 30% oxygen for clinical use in Japan (20,27). In contrast, 2.9% hydrogen gas was used in other studies (17,18).…”

“…Recently, strong clinical and experimental evidence has shown that hydrogen, administered by gas inhalation or ingestion of an aqueous hydrogen-containing solution, has potent protective cellular effects in various diseases (4,5,10,20,21,24,26,27), but without major adverse effects (5). Previous studies have shown that hydrogen has antioxidant, anti-apoptotic, antiinflammatory, and cytoprotective properties that are beneficial to the cell (5).…”

“…Soon after administration of hydrogen-rich saline or normal saline, rats were placed individually in a sealed Plexiglas box with inflow and outflow outlets. Hydrogen gas group rats were exposed to nitrogen-based standard mixed gas with 1.3% hydrogen and 30% oxygen (Saisan Co., Ltd., Saitama, Saitama, Japan) for 3 hours daily for 3 days, whereas other group rats were exposed to nitrogen-based high pressure mixed gas with 30% oxygen (without hydrogen) (Saisan Co., Ltd.) (20). The hydrogen concentration of 1.3% was applied as a safe level in high pressure mixed gas containing 30% oxygen.…”

“…Images were observed and captured at magnification 400× with a microscope (Axio Imager.A1, Carl Zeiss) equipped with a digital camera system (Axio Cam MRc 5, Carl Zeiss). For quantitative analysis, the number of 8-OHdG-positive cells was counted in the perihematoma region by an observer unaware of the experimental groups as described previously (20). eight sampling regions were randomly placed along the perihematoma region, and the average count was calculated for analysis.…”

“…Hydroxyl radicals and peroxynitrites are very strong ROS that react indiscriminately with nucleic acids, lipids, and proteins, resulting in DNA fragmentation, lipid peroxidation, and protein inactivation (4,5,10,20,21,24,26,27). edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a potent scavenger of hydroxyl radicals and is used for the treatment of ischemic stroke in Japan.…”