To explore the mechanism of verbascoside (VB) on dopamine cell protection in the mice with Parkinson's disease (PD).

A total of 63 C57/BL male mice were enrolled as the experimental subjects and randomly divided into blank control group, 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) group, 10 mg/kg group, 30 mg/kg group, 60 mg/kg group, 120 mg/kg group and 180 mg/kg group, with 9 mice in each group. After successful modeling, the behavioral changes of the mice were evaluated by mining, climbing pole and hanging experiments. Hematoxylin-eosin (HE) and Nissl staining were used to evaluate the neuron counts in the substantia nigra of the mice. Immunohistochemistry method and immunofluorescence staining were used to evaluate the tyrosine hydroxylase (TH) -positive and positive cell counts in the substantia nigra, respectively. Western blotting was used to detect the expression of TH protein in the substantia nigra of the mice. HE staining was used to evaluate liver and kidney cell morphology and cell count. Finally, the optimal dose group screened for proteomic analysis was performed.

(1) In the mine experiment, the total distance and the distance of the 120 mg/kg group were higher than those of the MPTP group and other concentration gradient groups (all P<0.05). In the pole climbing experiment, the pole climbing time of the 120 mg/kg group was both higher than that of the MPTP group and other concentration gradient groups (all P<0.05). In the pole climbing experiment, the pole climbing time of the 120 mg/kg group was both higher than that of the pole climbing experiment. The suspension scores of the MPTP group and the other concentration gradient groups (all P<0.05). In the suspension experiment, the suspension scores of the 120 mg/kg group were higher than those of the MPTP group and the 10 mg/kg group (all P<0.05). (2) In HE staining, Niss-type staining and immunohistochemistry method, the cell count and tan pixel proportion of the 120 mg/kg group were higher than those of the MPTP group and other concentration gradient groups (all P<0.05). (3) In immunofluorescence, the average fluorescence intensity of the 120 mg/kg group was higher than that of the MPTP group and other concentration gradient groups (all P<0.05). (5) In Western blotting, the relative expression of TH in the 120 mg/kg group was higher than that in the MPTP group and other concentration gradient groups (all P<0.05). (6) Proteomic analysis showed that compared with the 120 mg/kg group and the MPTP group, there were 181 proteins with statistical differences, including 83 up-regulated proteins and 98 down-regulated proteins. There were up to 85 differential proteins localized to the nucleus of subcellular nucleus, and gene ontology (GO) functional analysis showed that there were up to 6 biological processes directly related to immunity (BP). KEGG pathway analysis showed the highest level of enrichment with arginine biosynthesis (all P<0.05).

VB with the dose of 120 mg/kg has a protective effect on DA neurons in PD mice, and this protective effect may be related to a variety of biological processes including arginine biosynthesis.