银杏叶提取物对星形胶质细胞诱导型一氧化氮合酶基因表达的调控

Regulatory effect of Ginkgo biloba extract on expression of iNOS gene in astrocytes

目的研究银杏叶提取物(EGh761)对星形胶质细胞合成一氧化氮(NO)的作用以及对共培养的小脑颗粒神经元的作用。方法以脂多糖(LPS)和IFN-γ诱导体外培养的大鼠星形胶质细胞表达诱导型一氧化氮合酶(iNOS),产生NO作为病理条件下胶质细胞过度活化的实验模型,应用逆转录基因扩增技术和蛋白质印迹技术检测EGb761对星形胶质细胞中iNOS基因表达的影响,并探讨这一调控作用的分子机制。结果EGb761能明显降低星形胶质细胞中iNOS mRNA和蛋白质的表达、减少NO 的生成、防止活化的胶质细胞损伤共培养神经元,抑制IκB-α的降解和阻止p65/RelA进入细胞核,提示EGb761对iNOS基因表达的抑制作用依赖于NF-κB信号通路。结论EGb761可能对与胶质细胞过度活化有关的神经系统疾病具有治疗、预防的作用。

OBJECTIVE To study the effects of Ginkgo biloba extract （EGb761） on iNOS expression and neuronal injury induced by LPS and IFN-γ. METHODS Upon stimulation with lipopolysacchuride（LPS） and interferon-γ（IFN-γ）, inducible nitric oxide synthase（iNOS） was expressed in cultured rat astrocytes, which caused the consequent generation of nitric oxide, and induced neuronal injury in astrocyte/cerebellar granule neuron co-cultures. The effects of EGb761 on the expression of iNOS gene in stimulated primary astrocytes were studied by Western blotting and reverse transcription polymerase chain reaction techniques. RESULTS The results showed that EGh761 decreased the expression of iNOS at both protein and mRNA level, and protected cerebeilar granule neurons from death. Further investigation showed that EGb761 signiticanfly inhibited the degradation of IκB-α, and blocked the translocation of p65/RelA into the nuclei. EGb761 inhibited the expression of iNOS by modulating the NF-κB pathway. CONCLUSION The results suggest EGb761 is a potential substance for the prevention and therapy of neuronal diseases which are related with the over activation of glial ceils.