3-硝基丙酸多次化学预处理对多巴胺能神经元的保护作用

Protective effect of 3-NP repetitive preconditioning on dopaminergic neurons

目的探讨3-硝基丙酸(3-NP)多次化学预处理对多巴胺能神经元的保护作用及可能机制。方法应用MPTP(30mg/kg)在C57BL小鼠上复制帕金森病模型,以3-NP(20mg/kg)行预处理,检测小鼠中脑黑质凋亡率和转录因子c-Jun的阳性细胞数量及c-Jun的蛋白水平;应用MPP+(0.25mmol/L)在SH-SY5Y细胞制作帕金森病模型,以3-NP(0.2mmol/L)进行预处理,并将携带显性突变体c-JuncDNA片段的真核表达载体质粒pcDNA3(HA)-Jun-dn转染SH-SY5Y细胞,检测各组细胞的c-Jun表达水平及凋亡率。结果小鼠中脑黑质凋亡率:MPTP组较对照组明显升高(P<0.01),3-NP单次、多次预处理后均明显降低(P<0.05,P<0.01);c-Jun阳性细胞数:MPTP组较对照组明显增加(P<0.05),3-NP单次预处理组与MPTP组比较元明显差异,3-NP多次预处理后明显降低(P<0.05);c-Jun蛋白水平:与其阳性细胞数变化一致;细胞凋亡率:MPP+组较对照组明显升高,3-NP单次、多次预处理组细胞凋亡率明显降低(P<0.05,P<0.01);c-Jun蛋白水平变化与中脑黑质一致;经pcDNA3(HA)-Jun-dn转染的细胞,其c-Jun的表达较未转染细胞明显降低(P<0.01),其凋亡率也下降(P<0.01)。结论3-NP单次、多次预处理对多巴胺能神经元确有保护作用,多次预处理保护效果更强,其机制与抑制转录因子c-Jun的表达,降低其蛋白水平有关。

Objective To investigate the protective effect of 3-NP repetitive preconditioning on dopaminergic neurons.Methods Parkinson＇s disease model were made on C57BL mouse with MPTP （30 mg/kg）. 3-NP were administered to produce preconditioning before MPTP used. The apoptosis ratio and expression of c-Jun in the substantia nigra were assayed. MPP ＋ were used to made parkinson＇ s disease model in vitro. 3-NP were incubated to produce preconditioning;The fragment of dominant mutant c-JuncDNA carried by eukaryon plasmid pcDNA3 （ HA）-jnn-dn was transfected into SH-SY5Y cells. The expression of c-Jun and the apoptosis ratio of SH-SY5Y cells were assayed. Results In MPTP group,the ratio of apoptosis was increased significantly. After 3-NP preconditioning, apoptosis was decreased significantly and the effect of repetitive preconditioning was better than that of single preconditioning. The expression of c-Jun was increased in MPTP group and no obviously changes were observed after 3-NP single preconditioning, but decreased after 3-NP repetitive preconditioning. In the transfection group, the expression of c-Jun was decreased and the apoptosis ratio was lower than that without transfection group. 3-NP repetitive preconditioning could decrease the expression of c-Jun and apoptosis ratio. Condusion 3-NP preconditioning exerts protective effect on dopaminergic neurons and the effect of repetitive preconditioning was better than single preconditioning.