Pilose Antler Extracts (PAEs) Protect against Neurodegeneration in 6-OHDA-Induced Parkinson's Disease Rat Models

Parkinson's disease (PD) is one of the most common neurodegenerative diseases worldwide. Although dopamine replacement therapy mitigates motor dysfunction in PD patients, there are no therapeutics that are currently available to reverse neuronal cell death in the substantia nigra pars compacta (SNc), which is the main region for dopamine loss in PD patients. The protein concentration of the Pilose antler extracts (PAEs) was estimated using the Bradford Protein Assay Kit. Hematoxylin and eosin (HE) staining was used to evaluate the protective effect of PAEs on 6-OHDA induced cell death in PD model rats. Immunohistochemistry (IHC) was used to detect the tyrosine hydroxylase (TH) positive neuronal cell in SNc. HPLC-MS was used to detect dopamine (DA), 3,4-Dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and glutamate (Glu) levels in the striatum and cerebrospinal fluid (CSF). The amino acid level in the striatum and CSF was measured by HPLC-FLD. Protein expression of growth associated protein-43 (GAP-43) and neurofilament heavy polypeptide (NF-H) was measured using western blotting. The components of PAEs through blood vessels were detected by HPLC/MS/MS. In this study, PAEs with proteins ranging from 10 kDa to 250 kDa molecular weight was administered to 6-OHDA-induced PD rats. We found that PAEs inhibited 6-OHDA-induced neuronal cell death and TH-positive neuronal loss in SNc. PAEs administration also increased the levels of DA, DOPAC, and 5-HT, in addition to DOPAC/DA and HVA/DA indexes in the CSF and Striatum of 6-OHDA induced rats. Conversely, PAEs decreased the levels of Glu and GABA. Treatment with PAEs and Madopar increased GAP-43 and NF-H expression in the SNc and striatum. Proteomic analysis using LC/MS/MS indicated that 11 components of PAEs may have neuropharmacological effects. These results demonstrate that PAEs protects against 6-OHDA induced toxic effects in the PD rat models. Intragastric administration of PAEs may be a novel therapeutic strategy for neurodegenerative disorders like PD.