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目的:研究1-甲基-4-苯基-1、2、3、6-四氢吡啶(MPTP)诱导6月龄快速老化小鼠(SAMP8)黑质纹状体急性损伤,以及血红素加氧酶-1(HO-1)的表达变化,探讨其与MPTP导致的SAMP8小鼠黑质纹状体系统损害的关系。方法:给6月龄健康雄性SAMP8小鼠背部皮下注射MPTP 20mg/(kg.次),连续注射4次,每次间隔2 h;对照组注射等量生理盐水。在注射后6 h、24 h、3 d和8 d处死小鼠留取脑组织标本,用免疫组织化学技术检测小鼠黑质、纹状体的酪氨酸羟化酶(TH)和HO-1,以计数黑质多巴胺能神经元数量及其投射纤维的改变,及HO-1阳性细胞的变化;用Westernblot方法检测TH和HO-1蛋白表达的变化。结果:MPTP致6月龄SAMP8小鼠各时间点TH阳性神经元分别减少14.23%(P<0.05),23.85%(P<0.01),36.77%(P<0.01),45.9%(P<0.01),24 h与3 d比较有显著性差异(P<0.05),神经元的丢失以24 h至3 d最为显著;MPTP组随时间延长纹状体区酪氨酸羟化酶免疫反应阳性染色逐渐变浅淡,不均匀,于注射后24 h明显,第8天最为浅淡;同时TH蛋白表达具有相同变化。但仅在注射后3 d小鼠纹状体区见到大量HO-1阳性细胞,同时HO-1蛋白表达增高,具有统计学意义,其余各时间点及对照组未见HO-1阳性细胞。中脑区HO-1阳性细胞及蛋白表达在各时间点均未见显著变化。结论:MPTP导致6月龄SAMP8小鼠黑质纹状体系统急性损伤,产生多巴胺能神经元数量减少及蛋白表达降低;其黑质纹状体HO-1的高表达是一过性短暂的,它在PD中的作用是有限的。
AIM: To investigate the acute injury induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in nigrostriatal tissue of 6-month-old aged mice (SAMP8) Oxygenase-1 (HO-1) expression changes, to explore its MPTP-induced SAMP8 mouse nigrostriatal system damage. Methods: 6-month-old healthy male SAMP8 mice were subcutaneously injected MPTP 20mg / (kg) twice a day for 2 hours at a time. The control group was injected with the same amount of normal saline. The mice were sacrificed at 6 h, 24 h, 3 d and 8 d after injection. The contents of tyrosine hydroxylase (TH) and tyrosine hydroxylase (TH) in substantia nigra and striatum were detected by immunohistochemistry. 1 in order to count the number of substantia nigra dopaminergic neurons and their changes of projection fibers and HO-1 positive cells. Western blot was used to detect the expression of TH and HO-1 protein. Results: The number of TH positive neurons decreased by 14.23% (P <0.05), 23.85% (P <0.01), 36.77% (P <0.01), 45.9% (P <0.01) , 24 h and 3 d (P <0.05). The neuronal loss was the most significant between 24 h and 3 d. In the MPTP group, the positive staining of tyrosine hydroxylase immunoreactivity gradually increased in the striatum Pale, uneven, obvious at 24 h after injection, the most light on the 8th day; at the same time TH protein expression with the same changes. However, only a large number of HO-1 positive cells were seen in the striatum of mice 3 days after injection, and the expression of HO-1 protein was increased at the same time, with statistical significance. No HO-1 positive cells were observed at other time points and in the control group. There was no significant change of HO-1 positive cells and protein expression in midbrain area at all time points. CONCLUSION: MPTP resulted in the acute injury of nigrostriatal system in 6-month-old SAMP8 mice, which resulted in the decrease of the number of dopaminergic neurons and the decrease of protein expression. The high expression of HO-1 in nigrostriatum was transiently transient, Its role in PD is limited.