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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-nitropropionic acid (3-NP) on dopaminergic neurons and its possible mechanism. Methods MPTP (30mg / kg) was used to replicate Parkinson’s disease model in C57BL mice and pretreated with 3-NP (20mg / kg) to detect the apoptosis rate of midbrain and the positive expression of c-Jun Cell number and c-Jun protein level. The model of Parkinson’s disease was established by using MPP + (0.25mmol / L) in SH-SY5Y cells and pretreated with 3-NP (0.2mmol / L) The eukaryotic expression plasmid pcDNA3 (HA) -Jun-dn of c-JuncDNA was transfected into SH-SY5Y cells to detect the expression of c-Jun and the apoptosis rate. Results The apoptotic rate of substantia nigra in MPTP group was significantly higher than that in control group (P <0.01). The 3-NP level was significantly decreased in single and multiple pretreatment groups (P <0.05, P <0.01). C The number of -Jun positive cells in MPTP group was significantly higher than that in control group (P <0.05). Compared with MPTP group, 3-NP single pretreatment group was significantly different (P <0.05) ; The level of c-Jun protein was the same as the number of positive cells. The rate of apoptosis was significantly higher in MPP + group than that in control group (P <0.05, (P <0.01). The changes of c-Jun protein level were consistent with those of midbrain substantia nigra. The expression of c-Jun in pcDNA3 (HA) -Jun-dn transfected cells was significantly lower than that in untransfected cells , The apoptosis rate also decreased (P <0.01). Conclusions Single and multiple pretreatment of 3-NP can protect the dopaminergic neurons, and the protective effect of multiple pretreatment is stronger. Its mechanism is related to inhibiting the expression of transcription factor c-Jun and decreasing its protein level.