Abstract: ObjectiveTo assess rat behavior, observe apoptotic morphology of neurons and measure expression of caspase-3 in substantia nigra(SN) of Parkinson's disease(PD) animal model. Methods6-OHDA was stereotacticly injected into the right striatum of the rats at two sites to produce PD models. After 5 weeks, the behavior tests including modified Morris Water Maze and narrow beam test were measured. Then tyrosine hydroxylase (TH) histochemistry, Hoechst 33258 staining, Western blotting for caspase-3 in right substantia nigra was separately conducted.ResultsEscape velocity significantly decreased and its latency was obviously enlarged in modified Morris Water Maze, and the latency and total time in narrow beam test were also markedly increased (P<0-05) in 15 successful PD rats compared with either the sham group or the normal group. Furthermore, there were obvious less TH-positive neurons in lesioned SN while more apoptotic cells appeared there. In addition, the expression of caspase-3 was highly upregulated in lesioned SN.Conclusion6-OHDA induced neuronal apoptosis in SN is associated with high levels of caspase-3, and the results of rat behavior tests are correspondent with the morphological changes including TH immunohistochemistry and Hoechst 33258 staining. Thus modified Morris Water Maze and narrow beam test are beneficial for assessments of effects of new drugs in PD animal model.

Key words: Parkinson's disease (PD), 6-hydroxydopamine, substantia nigra, behavior, apoptosis