RESUMO
Objective To observe the distribution of dopaminergic neurons in SNpc and to establish standard curve in normal mice so as to measure the changes of dopaminergic neurons in number in SNpc of the mice toxicated with MPTP. Methods Ten male C57BL6 mice aged 8-12 weeks, weight 20-22 g, were randomized to receive 20 mg/kg MPTP or physical saline every 3 h for 4 times, then killed 7 d later. The mouse mesocerebrum was taken out and fixed, frozen, sectioned. All sections containing SNpc were observed under the guide of mouse brain atlas. Every other sections were chosen to stain tyrosine hydroxylase (TH) to show dopaminergic neurons immunohistochemically. The TH positive cells in SNpc were counted in each section and the standard curve was established. Results The standard curve of SNpc compact part position and TH positive cells was established. By comparing the standard curves for the MPTP intoxicated mice and the saline mice, TH positive cells in SNpc from MPTP toxicated mice decreased significantly, which confirmed the validity and feasibility of the standard curve. Conclusion The establishment of standard curve greatly facilitates the comparison of specimen from different groups and makes the assessment of dopaminergic neuron loss more accurate and efficient. The standard curve can serve as an excellent reference curve for the assessment of dopaminergic neurons in SNpc in normal C57BL6 mice.