Effect of hydrogen on endoplasmic reticulum stress during hypoxia-reoxygenation in PC12 cells

Objective To investigate the effect of hydrogen on endoplasmic reticulum stress during hypoxiareoxygeuation(H/R)in PC12 cells.Methods PC12 cells were randomly divided into 4 groups:normal control group(group NC),positive control group(group PC),H/R group and hydrogen group(group H).In group NC.the cells were cuhnred routinely for 25 h.In group PC,the cells were cultured routinely for 1 h and then in RPM1-1640 culture medium saturated with hydrogen for 24 h.In H/R group,the cells were exposed to 1 h of hypoxia followed by 24 h of reoxygenation.In group H,the cells were exposed to 1 h of hypoxia and then reoxygenated in RPMI-1640 culture medium saturated with hydrogen for 24 h.Hypoxia-reperfusion was produced by 1 h exposure of cells to 5％ CO2 in an incubator at 37 ℃ in RPMI-1640 culture medium containing Na2S2O4 with the final concentration of 5.0 mmoI/L,followed by 24 h reoxygenation in the normal RPMI-1640 culture medium.The relative rate of cell proliferation was detected by WST-1,The concentration of MDA was determined by thiobarbituric acid method.The expression of caspase-3 was determined by immuno-histochemistry.The expression of activating transcription factor-4(ATF4)mRNA and C/EBP homologous protein(CHOP)mRNA was determined by RTPCR.Results Compared with groups NC and PC,the relative rate of cell proliferation was significantly decreased,MDA concentration was significantly increased,and the expression of caspase-3,ATF4 mRNA and CHOP mRNA was up-regulated in group H/R,and the expression of ATF4 mRNA and CHOP mRNA was up-regulated in group H(P ＜ 0.05).There was no significant difference in the relative rate of cell proliferation,MDA concentration,and the expression of caspase-3,ATF4 mRNA and CHOP mRNA between groups NC and PC(P ＞ 0.05).Compared with group H/R,the relative rate of cell proliferation was significantly increased,MDA concentration was significantly decreased,and the expression of caspase-3,ATF4 mRNA and CHOP mRNA was down-regulated in group H(P ＜ 0.05).Conclusion Hydrogen can decrease cell apoptosis and attenuate H/R injury to PC12 cells through inhibiting endoplasmic reticulum stress. Key words: Hydrogen bonding; Cell hypoxia; Oxygen; Endoplasmic reticulum stress