五味子乙素通过抑制TLR4/NF-κB信号通路减轻PD小鼠炎症反应及DA能神经元凋亡

Schisandrin B alleviates inflammatory response and apoptosis of DA neurons in PD mice by inhibiting TLR4/NF-κB signaling pathway

目的:探讨五味子乙素(Sch B)对帕金森病(PD)模型小鼠炎症反应及TLR4/NF-κB信号通路的影响。方法:30只C57BL/6雄性小鼠随机分为正常组、模型组和Sch B组,10只/组。腹腔注射1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)建立PD模型,Sch B组小鼠给予Sch B灌胃14 d。步态实验观察各组小鼠行为学表现;免疫荧光染色检测小鼠黑质区酪氨酸羟化酶(TH)荧光强度;ELISA法测定黑质区IL-1β、IL-6和TNF-α水平;Western blot检测黑质区TH、Bcl-2、Bax、TLR4和p-NF-κB p65表达。结果:与正常组相比,模型组小鼠左前爪步幅显著减小,后爪步宽明显增大,中脑黑质中TH荧光强度显著减弱、表达量减少,IL-1β、IL-6和TNF-α水平明显升高,Bcl-2与Bax蛋白表达比值显著减少,TLR4和p-NF-κB p65表达明显增加。与模型组相比,Sch B组小鼠的步幅明显增大、步宽显著减小,中脑黑质TH荧光强度增强、表达量增加,IL-1β、IL-6和TNF-α水平明显降低,同时Bcl-2与Bax蛋白表达比值显著增加,TLR4和p-NF-κB p65表达明显减少。结论:Sch B能够缓解PD小鼠脑部炎症反应及多巴胺(DA)能神经元凋亡,这可能与其抑制TLR4/NF-κB信号通路有关。

Objective:To investigate the effect of Schisandrin B(Sch B)on inflammatory response and Toll-like receptor 4/nuclear transcription factor-κB(TLR4/NF-κB)signaling pathway in Parkinson’s disease(PD)mice.Methods:Thirty C57 BL/6 male mice were randomly divided into normal group,model group and Sch B group.The intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrah-ydropyridine(MPTP)was used to establish PD model and Sch B was given intragastrically for 14 days.Gait analysis was carried out to evaluated the behavioral differences.Fluorescence intensity of TH in the substantia nigra was observed by immunofluorescence staining.ELISA was used to detect the levels of IL-1β,IL-6 and TNF-αin the supernatants of substantia nigra.The expressions of TH,Bcl-2,Bax,TLR4 and p-NF-κB p65 in the extracted protein of substantia nigra were determined by Western blot.Results:Compared with the normal group,the stride length of left fore limb of mice in model group decreased and stance width of hind limb increased significantly,accompanied by obviously weakened fluorescence intensity and decreased expression of TH,increased levels of IL-1β,IL-6 and TNF-α,reduced ratio of Bcl-2/Bax and enhanced expressions of TLR4 and p-NF-κB p65 in the substantia nigra.Compared with the mice in model group,Sch B treatment increased the stride length of left fore limb and decreased the stance width of hind limb,enhanced the fluorescence intensity and expression of TH,reduced the levels of IL-1β,IL-6 and TNF-α,increased the ratio of Bcl-2/Bax and decreased the expressions of TLR4 and p-NF-κB p65 in the substantia nigra significantly.Conclusion:Sch B can alleviate the inflammatory response in substantia nigra and protect dopaminergic neurons from apoptosis of PD mice,which may be related to the inhibition of TLR4/NF-κB signaling pathway.