Effects Of Exogenous Hydrogen Sulfide On Hippocampal Neurons Induced By OGD/R And Its Mechanism

Objective To investigate the effects of exogenous hydrogen sulfide (H2S) on ingury of rat hippocampal neurons induced by oxygen-glucose deprivation and recovery (OGD/R) and explore its intervention effects on hypoxia-induced factor-la(HIF-la).Methods Hippocampal neurons are isolated from embryonic day16-18(E16-18) rat embryos. Hippocampus was immediately removed and digested with0.25%trypsin. The neurons were isolated and cultured at37℃for7days and neuron-specific enolase(NSE) was detected by immunohistochemical staining method to identify neurons. At8th day, the neurons were placed in deoxygenated glucose-free medium and exposed to95%N2-5%CO2in an aiaight chamber for1hour, and then replaced the glucose-free medium with original medium, and returned the cultures to a standard incubator in5%CO2at37℃and incubated for another24h. The neurons were divided into3groups: group Ⅰ control; group Ⅱ OGD/R, group Ⅲ OGD+NaHS, the latter was divided into5subgroups:groupⅢ1-5,25,50,100,200,400μmol/L NaHS. Then cell viability was quantified by MTT method, the level of lactate dehydrogenase (LDH) were detected, apoptosis was measured by Annexin V FITC/PI Apoptosis Kits, RT-PCR was used to assay Caspase-3mRNA and HIF-1α mRNA in neurons in all groups.Results Compared with control group, the LDH level, apoptosis and expression of Caspase-3and HIF-la mRNA in group Ⅱ were significantly increased, the cell viability was significantly decreased (p<0.01). There is no significant differences in the LDH level, apoptosis, expression of Caspase-3and HIF-1α mRNA and the cell viability between group Ⅱ and group Ⅲ1(P>0.05). Compared with group Ⅱ, the LDH level, apoptosis and expression of Caspase-3mRNA in group Ⅲ2-4were significantly decreased, the cell viability and expression of HIF-1α mRNA were significantly increased (p<0.01). Compared with group Ⅱ, the LDH level, apoptosis and expression of Caspase-3mRNA in group Ⅲ5were significantly increased, the cell viability and expression of HIF-1α mRNA were significantly decreased (p<0.01).Conclusions H2S of low concentration has no significant effects on ingury of rat hippocampal neurons induced by OGD/R. H2S of moderate doses can protect rat hippocampal neurons from OGD/R ingury and H2S of high concentration can aggravate ingury. The expression of HIF-1αmRNA in rat hippocampal neurons was increased after OGD/R, and the protective role of H2S is associated with increase in the expression of HIF-1αmRNA.