α-Synuclein与帕金森病临床前期动物模型研究

On NACP and the preclinic animal model of Parkinson's Disease

用 1 甲基 4 苯基 1 ,2 ,3 ,6 四氢吡啶 (MPTP)小剂量慢性给药建立帕金森病临床前期动物模型 ,观察小鼠脑组织形态学、生物化学及行为学方面的变化 ,同时对实验组小鼠黑质内α 突触核蛋白 (α synuclein ,NACP)阳性细胞数与纹状体内的突触数量进行动态变化的研究 ,探讨NACP与突触损伤之间的关系。C5 7BL/ 6j小鼠 60只 ,根据给药时间长短分为 5、1 0、1 5、2 0d 4组 ,腹腔注射MPTP〔4mg/ (kg·d)〕 ,正常对照组注射生理盐水。最后一次给药后 7d进行脑组织取材 ,分别进行NACP免疫组化染色、黑质纹状体形态学观察及纹状体内多巴胺含量的检测。发现 :1 )黑质内NACP免疫组化阳性细胞数在 5d组为最高峰 ,随后各组逐渐减少。 2 )电镜下黑质内除见固缩的神经细胞外 ,其他的神经元也有超微病理改变如线粒体肿胀、粗面内质网减少等。 3 )各给药组小鼠纹状体内的多巴胺含量与正常对照组相比均有明显下降 (P <0 .0 1 ) ,各给药组之间无明显差异 (P >0 .0 5 )。实验结果证实 :1 )低剂量MPTP慢性给药小鼠虽不能诱导出帕金森病的症状 ,但免疫组化、多巴胺含量测定及超微病理出现的改变可以作为帕金森病临床前期动物模型的参考指标。 2 )在MPTP慢性给药小鼠的早期阶段 ,黑质内神经细胞损伤时NACP表达水平增高可能是神?

The objective was to explore whether the chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropydine (MPTP)-treated mice could be treated as the model of sporadic Parkinson's disease at preclinic stage by the research on the morphological, biochemical and behavioral changes of these mice brain, and to explore the relation between NACP and synaptic lesion during the early stage of Parkinson's disease by research on the relation between the alteration of the number of NACP-positive neurons and the alteration of the number of synapse of striatum in the chronic MPTP-treated mice model. Materials and Methods: C57BL/6j mice received intraperitioneal injection of MPTP 〔4 mg/(kg·d)〕, and these mice were divided into four groups according to the days of MPTP injection. The following tests were done: 1) Cryostat sections were studied by immunohistochemistry for NACP. 2) The morphmetric analysis of the striatum was done. 3) The neuropathological examination of the substantia nigra and the striatum was carried out. 4) Dopamine of the striatum was measured by HPLC-ECD, Western-blot. Results: 1) The number of NACP positive neurons in the substantia nigra reached a peak value in the 5-day group and gradually decreased after that time. 2) Electron microscopic results revealed that the number of synapse in the striatum decreased obviously in the 5-day group. 3) There was a significant difference (P<0.01)on content of DA in the striatum between the control and MPTP-treated groups, but there was no significant difference (P>0.05) between every MPTP-treated group. Conclusions: 1) The chronic MPTP-treated mice can be treated as the preclinic model of Parkinson's disease. 2) It is possible that the transitory increase in NACP in early stage of MPTP-treated mice model of PD might represent a compensatory mechanism to the ongoing synaptic damage.