知母皂苷对脂多糖引起星形胶质细胞炎症因子释放的影响及机制

目的研究知母皂苷(SAaB)对脂多糖(LPS)诱导的星形胶质细胞(AC)炎症因子释放的抑制作用及JNK信号传导通路对其的影响。方法实验设对照组、LPS组、SAaB组和阻断剂组。ELISA法和Griess法分别测定各组AC培养液中TNF-α和NO的含量;Western blot检测AC磷酸化JNK和磷酸化c-Jun蛋白表达水平的改变;免疫荧光染色法观察AC的磷酸化ATF-2蛋白表达水平。结果 AC在LPS(10mg.L-1)刺激下TNF-α和NO的分泌、磷酸化JNK1、磷酸化c-Jun和磷酸化ATF-2蛋白表达水平与正常对照组比较均明显增高。特异性JNK特异性阻断剂SP600125(10μmol.L-1)可明显抑制LPS引起的TNF-α和NO产生增加以及磷酸化ATF-2蛋白表达水平;SAaB(1、10、100μmol.L-1)则可明显降低TNF-α和NO产生,下调磷酸化JNK、磷酸化c-Jun和磷酸化ATF-2的蛋白表达水平。结论 SAaB能明显抑制LPS诱导的大鼠皮层AC炎症因子的释放,这种作用可能与其下调JNK信号转导通路有关。

Effect of SAaB on the release of inflammatory factors induced by lipopolysaccharide in cultured astrocytes in rats

Aim To investigate whether Saponins from Anemarrhena asphdeloids Bge(SAaB) can protect cortical astrocytes from lipopolysaccharide(LPS)-in-duced release of inflammatory factors and to study the mechanisms responsible for this protective effect.Methods Cultured astrocytes were treated with LPS(10 mg·L-1) for 24 h,in the Absence or presence of SAaB(1,10 and 100 μmol·L-1) or the specific inhibitor of JNK SP600125(10 μmol·L-1),and harvested.Tumor necrosis factor-α(TNF-α) and nitric oxide(NO) generation were analysed respectively by ELISA and Griess technology.Western blot was performed to observe the level of phospho-JNK and phospho-c-Jun in cultured astrocytes.Immunofluorescent technology was performed to observe the level of phospho-activating transcription factor-2(ATF-2) protein expression.Results LPS induced a significant increase in phospho-JNK and phospho-c-Jun protein expression without affecting total protein levels,and increased the expression of phospho-ATF-2 and the release of TNF-α and NO in cultured astrocytes in rats.SP600125 significantly inhibited LPS-induced increase in the release of TNF-α and NO.SAaB obviously inhibited LPS-induced increase in the release of TNF-α and NO and the expression of phospho-JNK,phospho-c-Jun and phospho-ATF-2 protein in cultured astrocytes.Conclusion This study indicates that SAaB can inhibit the release of TNF-α and NO induced by LPS in cultured astrocytes through the suppression of JNK signal transduction pathway activity.