The Neuroprotective Effect And Mechanism Of Exogenous Hydrogen Sulfide On Cerebral Ischemia/reperfusion Injury In Rats

Part Ⅰ Neuroprotective mechanism of different concentration of hydrogen sulfide on cerebral ischemia-reperfusion injury in ratsObjective:To investigate the neuro-protective mechanism of exogenous hydrogen sulfide on cerebral ischemia-reperfusion (I/R) in rats.Methods:A total of288male Sprague-Dawley rats were randomly divided into4groups (n=72),including a sham-operation group (group Ⅰ),an I/R model group (group Ⅱ),a low dose NaHS group (group Ⅲ) and a high dose NaHS group (group Ⅳ). Reversible middle cerebral artery occlusion(MCAO) model was established by intraluminal suture method. However, the rats in sham-operation group were operated on without blockage of the middle cerebral artery. The occlusions in other groups were removed after2h, and20min before the removal of the occlusion,NS,3.2mg/kg NaHS, and6.4mg/kg NaHS were injected into the abdomens of rats in group Ⅱ, Ⅲ, and Ⅳ, respectively. At6h,24h,48h,and7d after the reperfusion,behavioral test was used to evaluate the neurological deficiency, and TTC staining was used to observe volume of cerebral infarction. In addition, the protein expression of heat shock protein20(HSP20) and tumor necrosis factor-alpha(TNF-α) in ischemic cortex were measured by immuno-histochemical method and Western blot.Results:Compared with I/R group, the neurological deficiency scores and volume of cerebral infarction of the group Ⅲ and Ⅳ were significantly decreased. Furthermore, the protein expression of HSP20in the group Ⅲ, and IV were markedly up-regulated while TNF-a markedly down regulated after the reperfusion.Conclusion:NaHS may exert anti-necrotic and anti-inflammatory function by inducing the expression of HSP20, inhibiting the expression of TNF-a, and reducing the size of cerebral infarction, and therefore, protecting the neuron after I/R injury. Part Ⅱ Neuroprotective mechanism of hydrogen sulfide on rats after cerebral ischemia-reperfusion by MAPKs pathwayObjective:To investigate the neuroprotective mechanism of exogenous hydrogen sulfide on rats after cerebral ischemia-reperfusion by MAPKs pathway.Methods:A total of360Sprague-Dawley male rats were randomly divided into three groups (n=90), including a sham-operation group, an ischemia-reperfusion(I/R) model group, NaHS (6.4mg/kg) group. Reversible middle cerebral artery occlusion(MCAO) model was established by intraluminal suture technique. The rats of sham-operation group were operated on while the middle cerebral artery was not blocked. At6h,24h,48h,3d and7d after the reperfusion, TTC staining was used to observe volume of cerebral infarction. The gene expression of ERK1/2、 P38and Nrf2in the hippocampus was measured by RT-PCR,while the protein expression of p-ERK1/2、t-ERK1/2、p-P38、t-P38and Nrf2was measured by Western blot or immunohistochemical method.Results:Compared with the I/R group, the volume of cerebral infarction and apoptosis of neurons of NaHS group was significantly lower. The Nrf2protein expression and phosphorylation of ERK1/2and P38in NaHS group increased significantly. Conclusion:Our animal data suggested that the Nrf2protein expression and the phosphorylation of ERK1/2and P38in the rat ischemic/reperfusion injury brain were decreased strongly after MCAO, NaHS supplement induced and increased significantly relieve the focal cerebral I/R injury, which has anti-oxidative stress effect on the cerebral ischemia-reperfusion injury.