Study On Neuron Protection Of Edaravone In Cultured Hippocampal Cells After Hypoxia-reoxygenation Injury And In Hippocampal Region In Rats After Subarachnoid Hemorrhage

Objective1. To demonstrate the protective effects of edaravone against neuronal anoxia-reoxygenation injury and to investigate the underlying mechanisms.2. To demonstrate the effects of edaravone on free radical injury and neuron apoptosis after subarachnoid hemorrhage (SAH) and to investigate the underlying mechanisms.Methods1. Acute lucose-oxygen deprivation and subsequent reoxygenation were used to establish anoxia-reoxygenation injury model in cultured hippocampal cells. Cells were treated with several concentrations of edaravone upon reoxygenation. Metabolic rate of MTT, content of malondialdehyde (MDA) and activity of NOS were measured by assay kits. The rate of apoptosis was detected by flow cytometry.2. a noncraniotomy model of SAH was produced by an endovascular suture through the internal carotid artery. Sprague-Dawley (SD) rats were randomly divided into three groups, including sham-operation group, SAH group and SAH with edaravone treatment group (EDA ??group). Based on the time point after SAH, these SD rats were derided into three subgroups: 24h, 48h and 72h groups. SOD activity and MDA content of brain homogenate were detected with the assay kits. In situ terminal deoxynucleotidyl tansferase-mediated deoxy-UTP nick end labeling(TUNEL) method was used to detect the number of apoptotic neurons of hippocampal CA₁ region. Immunohistochemistry technology was used to test the expression of Bcl-2 and Bax.Results1. Edaravone raised the metabolic rate of MTT(P＜0.05) and reduced malondialdehyde level and activity of NOS of anoxia-reoxygenation injury model in a dose-dependent manner compared with untreated group. The peak of neuroprotective effects occurred at the dose of 100 and 300μmol/L(P＜0.01). Cell apoptotic rate was significantly decreased following edaravone treatment(P＜0.05).2. Edaravone raised activity of SOD(P＜0.05) and reduced MDA content (P＜0.05) significantly compared with SAH group. The number of apoptotic cells in hippocampal pyramidal CA₁ region in EDA group significantly decreased. The expression of Bcl-2 increased in EDA group, while the expression of Bax decreased.Conclusion1. Edaravone has protective effect on hippocampal neurons against anoxia-reoxygenation injury by increasing metabolic rates of MTT, inhibiting lipid peroxidation, reducing activity of NOS and decreasing apoptosis.2. Subarachnoid hemorrhage causes secondary brain injury. Edaravone has neuroprotective effect of inhibiting free radicals injury and decreasing apoptosis. The increasing expression of Bcl-2 and the decreasing expression of Bax may play important roles in hippocampus neuronal apoptosis following SAH.