Protective Effect Of Hydrogen Gas On Neurons In Rat Hippocampus CA1 Region During Global Cerebral Ischemia/reperfusion Injury

Objective: To investigate the effect of inhalation of high concentrations hydrogen gas on neuronal damage in the rat hippocampus CA1 region during global cerebral ischemic/reperfusion injury. Methods: Four-vessel occlusion was used to establish the model of global cerebral ischemia/reperfusion injury in rats. One hundred and twenty healthy male Sprague-Dawley rats were randomly divided into 3 groups using a random number table: sham operation group(SH group, n=30), model group(4-VO group: during reperfusion inhaled 67% N2 and 33% O2, n = 45), treatment group(4-VO+H2 group: During reperfusion inhaled 67% H2 and 33% O2, n = 45). After 72 h and 9 d reperfusion, hippocampal CA1 region pyramidal neurons in every group were detected with Nissl staining, immunohistochemical neuron-specific nuclear protein(NeuN), specific protein antibody microglial cells(Iba1) staining and fluorescence double staining NeuN and Iba1 and observe the relationship of position between neurons and microglia. At the same time we used water maze experiment to measure spatial orientation and memory function and Golgi staining to detect the number of dendritic spines in neurons after 9 d reperfusion. Results: Compared with the 4-VO group,the neurons of hippocampus CA1 region are closer to normal in 72 h and 9 d 4-VO+H2 group, neuron form and the number of the neuron survival were increased significantly(P<0.05);Immunohistochemical staining results show that the number of neuron survival in 4-VO+H2 group was obviously higher than 4-VO group(P<0.05), the number of microglia 4-VO group was obviously higher than that of the 4-VO+H2 group(P<0.05). Water maze experiment results show that the swimming time in quadrant IV in the 4-VO+H2 group was longer than in the 4-VO group(P<0.05), Golgi staining showed that use the high power oil microscopically, the number of dendritic spines in 4-VO+H2 group are significantly more than 4-VO group(P < 0.01). Conclusions: Inhalation of high concentration hydrogen gas has excellent protective effect on the neurons and dendritic spines of rat hippocampal CA1 region during reperfusion, the mechanism may through inhibiting the microglia excitation and activation during global cerebral ischemia/ reperfusion.