葛根素对大鼠局灶性脑缺血后海马CA1区NMDA受体的影响及其意义

Effect of Puerarin on the Expression of NMDA Receptor in the Hippocampus CA1 Region after Focal Cerebral Ischemia in Rats

目的探讨葛根素对脑缺血后兴奋性氨基酸毒性的拮抗作用,阐明葛根素治疗缺血性脑血管疾病的机理。方法采用线栓法制备大鼠大脑中动脉局灶性脑缺血模型,在缺血后不同时间点应用葛根素进行治疗,运用2,3,5-三苯基-2H-四唑盐酸盐(TTC)染色观察梗死体积的变化,通过免疫组化方法观察脑缺血后海马CA1区N-甲基-D-天冬氨酸(NMDA)受体NR1亚基表达的变化。结果模型治疗2h组及12h组的梗死体积小于模型对照组各对应时间点(P<0.05),而24h组相比差异无统计学意义。与假手术组相比,模型对照组及模型治疗组海马CA1区阳性细胞数目均增加,差异均具有统计学意义(P<0.05);与模型对照组各对应时间点相比,模型治疗2h组、12h组海马CA1区阳性细胞数均下降(P<0.05),24h组虽有所下降,但差异尚无统计学意义。结论缺血12h以内应用葛根素治疗可以减少NMDA受体表达,从而间接证明脑缺血后早期应用葛根素可以拮抗兴奋性氨基酸的毒性作用,减轻神经细胞损伤。

Obiective To study the antagonistic action of Puerarin against the excitatory amino acid toxicity,and to further explore its brain protection mechanisms.Methods Focal cerebral ischemia model was set up with middle cerebral artery occlusion by intraluminal block in this study.After cerebral ischemia,Puerarin was administered at different time point.The volume of cerebral ischemia was assessed by TTC stain.NR1 positive neurons in hippocampus CA1 region was determined by immunohistochemistry SABC method.Results The cerebral ischemia volumes were smaller in 2 h and 12 h model treatment groups（P〈0.05）than those in model control groups,but no significant differences were observed in 24 h model treatment group.Compared with sham-operation group,the NR1-positive cells in himppocampal CA1 region were increased obviously（P〈0.05） in both model control and model treatment groups.Compared with model control groups,the NR1-positive cells in himppocampal CA1 were decreased obviously（P〈0.05） in 2 h and 12 h treatment groups.Conclusion The treatment of Puerarin within 12 h after ischemia can cut down the expression of NMDA receptor.This indicates that the puerarin treatment in earlier period after ischemia can indirectly rivalry toxic effect of excitatory amino acids,relieve neural injury.