β-asarone and levodopa co-administration protects against 6-hydroxydopamine-induced damage in parkinsonian rat mesencephalon by regulating autophagy: down-expression Beclin-1 and light chain 3B and up-expression P62

In this study, we investigated Beclin-1, light chain (LC)3B, and p62 expression in 6-hydroxydopamine (6-OHDA)-induced parkinsonian rats after -asarone and levodopa (l-dopa) co-administration. Unilateral 6-OHDA injection into the medial forebrain bundle was used to create the models, except in sham-operated rats. Rats were divided into eight groups: sham-operated group; 6-OHDA model group; madopar group (75mg/kg, per os (p.o.)); l-dopa group (60mg/kg, p.o.); -asarone group (15mg/kg, p.o.); -asarone+l-dopa co-administered group (15mg/kg+60mg/kg, p.o.); 3-methyladenine group (500nmol, intraperitoneal injection); and rapamycin group (1mg/kg, intraperitoneal injection). Then, Beclin-1, LC3B, and p62 expression in the mesencephalon were detected. The mesencephalon was also observed by transmission electron microscope. The results showed that Beclin-1 and LC3B expression decreased and that p62 expression increased significantly in the madopar, l-dopa, -asarone, and co-administered groups when compared with the 6-OHDA model. Beclin-1 and LC3B expression in the -asarone and co-administered groups were less than in themadopar or l-dopa groups, whereas p62 expression in the -asarone and co-administered groups was higher than in the madopar or l-dopa groups. In addition, a significant decrease in autophagosome was exhibited in the -asarone and co-administered groups when compared with the 6-OHDA group. Our findings indicate that Beclin-1 and LC3B expression decreased, whereas p62 expression increased after co-administration treatment. In sum, all data suggest that the co-administration of -asarone and l-dopa may contribute to the treatment of 6-OHDA-induced damage in rats by inhibiting autophagy activity.