Abstract: 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 MPTP4 mg/(kg·d)〕, and these mice were divided into four groups according to the days of MPTPinjection. 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.

Key words: Parkinson disease, NACP, animal model