Effect Of Hydrogen Gas On Endoplasmic Reticulum Stress And Neural Cell Apoptosis In Rats With Cerebral Ischemia-reperfusion Injury

Objective: To investigate the effects of inhaling of high concentrations hydrogen gas on the expressions of endoplasmic reticulum stress related protein,Glucose Regulated Protein 78（GRP78）and Caspase-12,and the neural cell apoptosis and the expressions of related proteins,Bcl-2 and Bax,in the rats with focal cerebral ischemia-reperfusion injury.Methods: Seventy-two healthy SPF male Sprague-Dawley rats were selected and then randomly divided into 4 groups of normal control（Con group: did not make any operation）,sham-operated group（Sham group: only isolated the carotid artery then sutured and during reperfusion inhaled 67%N₂+33%O₂）,cerebral ischemia-reperfusion injury group（I/R group: performed reperfusion after cerebral ischemia 1h and then inhaled 67%N₂+33%O₂）and inhalation of hydrogen gas group（H2 group: performed reperfusion after cerebral ischemia 1h and then inhaled 67%H2+33%O₂）（n=18 each）.Focal cerebral ischemia-reperfusion model was induced by using conventional method with filament.Neurological deficits score was assessed after cerebral reperfusion 24 h in four groups.The cerebral infarction severity and size were detected by 2,3,5-triphenyl tetrazolium chloride（TTC）staining,and neuronal apoptosis of brain cortex and apoptosis index（AI）were tested by TUNEL technique.Then the expressions of GRP78、Caspase-12、Bcl-2 and Bax were assessed with Western blot and immunohisto-chemistry.Results: Compared with groups Con and Sham,the neurological deficit score,cerebral infarction size,apoptosis index（AI）and the expression of GRP78、Caspase-12 and Bax in cerebral cortex were significantly increased and the expression of Bcl-2 in cerebral cortex were markedly decreased in groups I/R and H2（p<0.05）.Compared with group I/R,the neurological deficit score,brain infarction size,AI and the expression of Caspase-12 and Bax in cerebral cortex were markedly decreased while the expression of GRP78 and Bcl-2 was dramatically increased in group H2（p<0.05）.Conclusions: Inhaling of high concentrations hydrogen gas during reperfusion can really protect the I/R rats,which through inhibiting endoplasmic reticulum stress and restoring the function of endoplasmic reticulum by increasing the expression of GRP78 and decreasing the activity of Caspase-12 on cerebral ischemia-reperfusion injury,then attenuating neuronal apoptosis by down-regulating the expression of and Bax and up-regulating the expression of Bcl-2,and dramatically ameliorating the neurological score and decreasing the cerebral infarction size.