Hydrogen-Rich Saline is Cerebroprotective in a Rat Model of Deep Hypothermic Circulatory Arrest

Deep hypothermic circulatory arrest (DHCA) has been widely used in the operations involving the aortic arch and brain aneurysm since 1950s; but prolonged DHCA contributes significantly to neurological deficit which remains a major cause of postoperative morbidity and mortality. It has been reported that hydrogen exerts a therapeutic antioxidant activity by selectively reducing hydroxyl radical. In this study, DHCA treated rats developed a significant oxidative stress, inflammatory reaction and apoptosis. The administration of HRS resulted in a significant decrease in the brain injury, together with lower production of IL-1β, TNF-α, 8-OHdG and MDA as well as decreased activity of NOS while increased activity of SOD. The apoptotic index as well as the expressions of caspase-3 in brain tissue was significantly decreased after treatment. HRS administration significantly attenuated the severity of DHCA induced brain injury by mechanisms involving amelioration of oxidative stress, down-regulation of inflammatory factors and reduction of apoptosis.

Hydrogen Suppresses Hypoxia/Reoxygenation-Induced Cell Death in Hippocampal Neurons Through Reducing Oxidative Stress

Deep hypothermic circulatory arrest (DHCA) is a cerebral protection technique that has been used in the operations involving the aortic arch and brain aneurysm for decades. We previous showed that DHCA treated rats developed a significant oxidative stress and apoptosis in neurons. We here intend to investigate the protective the effect of hydrogen against oxidative stress-induced cell injury and the involved mechanisms using an in vitro experimental model of hypoxia/reoxygenation (H/R) on HT-22 cells. The model of H/R was established using an airtight culture container and the anaeropack. Measurement of mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) production was used H2DCFDA and JC-1 staining. Western blot was used for the quantification of Akt, p-Akt, Bcl-2, Bax and cleaved caspase-3 proteins. The microRNA (miRNA) profile in hippocampal neurons from rat model of DHCA was determined by miRNA deep sequencing. The elevation of ROS and reduction of MMP were significantly induced by the treatment with hypoxia for 18 h followed by reoxygenation for 6 h. Hydrogen treatment significantly reduced H/R-caused cell death. The levels of p-Akt (Ser 473) and Bcl-2 were significantly increased while Bax and cleaved caspase-3 were decreased by hydrogen treatment on the model of H/R. The expression of miR-200 family was significantly elevated in model of DHCA and H/R. Hydrogen administration inhibited the H/R-induced expression of miR-200 family in HT-22 cells. In addition, inhibition of miR-200 family suppressed H/R-caused cell death through reducing ROS production. These results suggest that H/R causes oxidative stress-induced cell death and that the hydrogen protects against H/R-induced cell death in HT22 cells, in part, due to reducing expression of miR-200 family. © 2015 S. Karger AG, Basel.