摘要目的 探讨中药光甘草定(GLA)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)致帕金森病(PD)海马区细胞外信号调节蛋白激酶(ERK)信号通路影响机制.方法 40只C57BL/6N小鼠按随机数字表法分为空白对照组、模型(MPTP)组、模型+光甘草定(MPTP+ GLA)组、模型+左旋多巴(MPTP+ LD)组,每组10只.采用腹腔注射MPTP(20 mg/kg)的方法制备小鼠PD模型,对照组注射同等剂量的生理盐水,MPTP+ GLA组将光甘草定灌胃(50 mg/kg),MPTP+ LD组左旋多巴灌胃(40 mg/kg),观察各组小鼠行为学变化并进行Y型电迷宫测试,检测海马区肿瘤坏死因子-α(TNF-α)、白细胞介素-18 (IL-18)、丙二醛(MDA)、超氧化物歧化酶(SOD)含量变化;免疫组化法测定海马中酪氨酸羟化酶(TH),ERK蛋白表达情况;Western印迹法检测海马中TH和ERK蛋白表达的变化.结果 MPTP组小鼠出现PD典型行为学表现,学习与记忆能力显著低于对照组;与对照组比较,MPTP组海马组织中TNF-α、IL-18、MDA含量均明显升高(P＜0.05),而SOD含量明显降低;与MPTP组比较,MPTP+ GLA组海马组织中TNF-α、IL-18、MDA含量均明显降低,而SOD含量明显增高[(TNF-α(μg/L):84.04±18.66比106.53±28.54;IL-18(μg/L):42.34±6.01比58.42±8.39;MDA(nmol/mg蛋白):2.64±0.52比3.78 ±0.31;SOD(U/mg蛋白):93.45±9.59比77.83±8.98)].免疫组化结果显示:与对照组比较,MPTP组TH蛋白表达减少而p-ERK蛋白表达明显增加;而MPTP+GLA组和MPTP+ LD组较MPTP组比较,TH蛋白表达增加,p-ERK表达明显减少.Western印迹检测结果显示:与对照组比较,MPTP组海马组织中TH蛋白表达减少而p-ERK蛋白表达明显增加;而MPTP+ GLA组和MPTP+ LD组较MPTP组比较,TH蛋白表达增加,p-ERK表达明显受到抑制.结论 传统中药光甘草定通过抑制ERK信号通路、抗氧化、减轻炎症等发挥对MPTP致PD小鼠学习记忆能力的保护作用.

abstractsObjective To investigate whether Glabridin had a beneficial effect on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced parkinson disease (PD) in mice,and explore the possible underlying mechanisms.Methods Forty C57BL/6N mice were randomly assigned into control group,MPTP group,Glabridin therapy(MPTP + GLA) group,Levodopa therapy(MPTP + LD) group,with 10 in each group.PD model was induced by intraperitoneal administration of MPTP(20 mg/kg).The mice in MPTP + GLA group,MPTP + LD group and control group were gavaged by glabridin (50 mg/kg),levodopa (40 mg/kg),and equal volume of normal saline,respectively.The behavioral changes of each group were observed and Y-type electric maze test was performed.The levels of tumor necrosis factor-α (TNF-α) and interleukin-18 (IL-18) were assayed by enzyme-linked immunosorbent assay (ELISA).Malondialdehyde (MDA),and superoxide dismutase (SOD) were analyzed.The protein expression of tyrosine hydroxylase (TH) and extracellular signal regulated protein kinase (ERK) protein expression of hippocampus tissue was detected using immunohistochemical techniques.TH and pERK protein expression of hippocampus tissue were detected by Western blotting.Results Mice in MPTP group showed typical behavior of PD,and the ability of learning and memory was significantly lower than those in the control group.Compared with MPTP group,the expressions of TNF-α and IL-18 were suppressed by GLA in hippocampus [TNF-α(μg/L):84.04 ± 18.66 vs 106.53 ±28.54;IL-18(μg/L):42.34 ±6.01 vs 58.42 ±8.39].The levels of MDA in hippocampus were down-regulated significantly in groups administrated with GLA [MDA (nmol/mgprot):2.64 ±0.52vs 3.78 ±0.31],while the SOD level increased after GLA administration[SOD(U/mgprot):93.45 ± 9.59 vs 77.83 ± 8.98].The results of immunohistochemistry showed the expression of TH protein in MPTP group was significantly decreased compared with that in control group,while the p-ERK protein in MPTP group was significantly increased.In MPTP + GLA group and MPTP + LD group,the expression of TH protein was significantly higher than that in MPTP group,and the expression of p-ERK protein was significantly lower than that in MPTP group.Western blot results showed that compared with control group,the expression of TH was significantly decreased,and p-ERK protein in hippocampus was significantly higherin MPTP group.The expression of TH protein was significantly higher in MPTP + GLA group than that in MPTP group,while the expression of p-ERK protein were inhibited by GLA in MPTP-induced PD mice.Conclusion Traditional Chinese medicine glabridin can protect the learning and memory ability of PD mice induced by MPTP by inhibition of the ERK signal pathway,antioxidation and reduction of inflammation.