Korean Red Ginseng Enhances Neurogenesis in the Subventricular Zone of 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Treated Mice

Modulation of endogenous neurogenesis would have a significant impact on future therapeutic strategies for neurodegenerative diseases. Recent studies have suggested that the enhancement of adult neurogenesis can be helpful in the treatment of Parkinson’s disease (PD). In this study, we investigated augmentative effects of Korean Red Ginseng (KRG) on neurogenesis in the subventricular zone (SVZ) of a PD mouse model. Male eight-week-old C57BL/6 mice were injected with vehicle or 20 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) four times at 2-h intervals. After the final injection, they were administrated vehicle or 100 mg/kg of Korean Red Ginseng extract and injected intraperitoneally with 50 mg/kg of 5’-bromo-2’-deoxyuridine-monophosphate (BrdU) once a day for 14 consecutive days. After the last pole test, dopaminergic neuronal survival in the nigrostriatal pathway, cell proliferation in the SVZ and mRNA expressions of neurotrophic factors and dopamine receptors in the striatum were evaluated. KRG administration suppressed MPTP-induced dopaminergic neuronal death in the nigrostriatal pathway, increased the number of BrdU- and BrdU/doublecortin-positive cells in the SVZ and enhanced the expressions of proliferation cell nuclear antigen, brain derived neurotrophic factor, glial cell derived neurotrophic factor, cerebral dopamine neurotrophic factor, ciliary neurotrophic factor, dopamine receptor D3 and D5 mRNAs. These results suggest that KRG administration augments neurogenesis in the SVZ of a PD mouse model.