Dynamic expressions of Beclin 1 and tyrosine hydroxylase in different areas of 6-hydroxydopamine-induced Parkinsonian rats.

Beclin 1, a regulator of the autophagy pathway, plays an important role in Parkinson's disease (PD). However, the crucial mechanism of Beclin 1 in PD remains unclear. Therefore, we investigated dynamic expressions of Beclin 1 and tyrosine hydroxylase (TH) in different brain areas of 6-OHDA-induced rats. Beclin 1 and TH expressions were analyzed by flow cytometry and immunohistochemistry, respectively. The results showed that Beclin 1 expressions were low in the sham group, but rose significantly after 6-OHDA injection. In the striatum and cortex, Beclin 1 increased at 3 h, peaking at 12 h, while in the hippocampus, it increased at 3 h and peaked at 24 h, then it declined slowly and remained steady at 72 h. Beclin 1 expression in the striatum and cortex areas was higher than that of the hippocampus area at 12 h. In addition, the time-course of TH expression in the striatum was similar to that in the mesencephalon. TH expression declined dramatically between 0 and 12 h. Pearson analysis showed significant negative correlations between TH and Beclin 1 expression in the areas we analyzed. While TH expression declined gradually between 12 and 72 h, significant positive correlations between TH and Beclin 1 were detected during that interval. This indicated that activation of Beclin 1-dependent autophagy may inhibit the loss of TH-positive neurons.