人参皂苷Rg1对帕金森病小鼠黑质中酪氨酸羟化酶及ephrinB2和磷酸化c-Jun表达的影响

Effect of ginsenoside Rg1 on the expressions of tyrosine hydroxylase,ephrinB2 and phosphorylated c-Jun in substantia nigra of mice with Parkinson's disease

目的观察人参皂苷Rg1对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)所致帕金森病(PD)模型小鼠黑质中酪氨酸羟化酶(TH)mRNA、ephrinB2和磷酸化c-Jun(p-c-Jun)蛋白表达的影响,探讨人参皂苷Rg1对PD的治疗作用及其可能机制。方法将27只C57BL/6小鼠随机分为对照组、模型组和人参皂苷Rg1组,每组9只。模型组和人参皂苷Rg1组小鼠腹腔注射MPTP构建PD模型。注射MPTP前,对照组和模型组小鼠腹腔注射生理盐水(1 mL·kg-1·d-1),人参皂苷Rg1组小鼠腹腔注射人参皂苷Rg1(10 mg·kg-1·d-1),连续3 d。通过爬杆实验观察小鼠行为学变化,2周后采用反转录聚合酶链反应检测小鼠黑质中TH mRNA的表达,免疫组织化学法检测小鼠黑质中ephrinB2及p-c-Jun蛋白的表达。结果不同时间点模型组小鼠的爬杆时间均显著长于对照组和人参皂苷Rg1组,差异均有统计学意义(P<0.05);模型组小鼠脑黑质中TH mRNA表达水平显著低于对照组和人参皂苷Rg1组,差异均有统计学意义(P<0.05,P<0.01);模型组小鼠脑黑质中ephrinB2、p-c-Jun阳性表达细胞数显著高于对照组和人参皂苷Rg1组,差异均有统计学意义(P<0.05)。结论 MPTP可能通过促进小鼠中脑黑质中ephrinB2、p-c-Jun的表达及诱导多巴胺能神经元细胞凋亡导致PD;人参皂苷Rg1可能通过降低小鼠中脑黑质中ephrinB2、p-c-Jun的表达并缓解多巴胺能神经元凋亡而改善PD症状。

Objective To explore the role of ginsenoside Rgl on treatment of Parkinson＇s disease（PD） and its mecha- nism by observing the effect of ginsenoside Rgl on the expressions of tyrosine hydroxylase（TH） mRNA, ephrinB2 and phos- phorylated e-Jun（p-c-Jun） protein in substantia nigra of mice with PD induced by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyri- dine （MPTP）. Methods Twenty-seven C57BL/6 mice were randomly divided into control group, model group and ginsenoside Rgl group, nine mice in each group. The mice in model group and ginsenoside Rgl group were used to make models of PD by intraperitoneal injection of MPTP. Before the intraperitoneal injection of MPTP ,the mice in control group and model group were pretreated with normal saline（ 1 mL·kg^-1· d^-1 ） , and the mice in ginsenoside Rgl group were pretreated with ginsenoside Rgl （10 mg · kg^-1·d^-1 ） by intraperitoneal injection for three days. The ethological changes of mice were observed by the pole test. The expression of TH mRNA in substantia nigra of the mice was determined with reverse transcription-polymerase chain reaction, and the expressions of ephrinB2 and p-c-Jun proteins in substantia nigra of the mice were detected by immuno- histochemistry after two weeks. Results The time of climbing pole of mice in model group was significantly longer than those of mice in control group and ginsenoside Rgl group at different time point（ P 〈 0.05 ）. The expression of TH mRNA in substantia nigra of mice in model group was significantly lower than that in control group and ginsenoside Rgl group（P 〈 0.05 ）. The number of ephrinB2 and p-c-Jun positive cells in substantia nigra of mice in model group was significantly higher than that in control group and ginsenoside Rgl group （ P 〈 0.05, P 〈 0.01 ）. Conclusion MPTP may promote the development of PD through inducing the expressions of ephrinB2 and p-c-Jun, and initiating dopamine neurons apoptosis. Ginsenoside Rgl may improve the symptoms of PD by decreasing the expressions of ephrinB2,p-c-Jun and restraining dopamine neurons apoptosis.