The role of ginsenoside Rg1 in antagonism of MPTP-induced iron accumulation in substantia nigra of mice

Objective To investigate the effect of ginsenoside Rg1 on the degeneration of dopaminergic neurons in the substantia nigra in 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) treated C57BL6 mice.Methods Mice were randomly divided into three groups:normal group,MPTP group and Rg1 pretreatment group.The mice were injected intraperitoneally with normal saline in normal group,30 mg/kg MPTP for 5 d in MPTP group,and 5 mg/kg Rg1 for 8 d and 30 mg/kg MPTP for 5 d in Rg1 pretreatment group,respectively.RT-PCR,immunohistochemistry,Perls' iron staining were used to observe the immunoreactive staining of dopamine transporter(DAT) protein,iron-positive cells and expression of DAT mRNA in the substantia nigra,respectively.HPLC was used to detect the contents of dopamine and its metabolites,dihydroxyphenylacetic acid and homovanillic acid in striatum of mice.Results The DAT immunoreactive staining and expression of DAT mRNA in the substantia nigra,and the contents of dopamine and its metabolites in the striatum were significantly lower in MPTP group than in control group(P0.01),while iron staining was significantly higher(P0.01).Compared with MPTP group,the DAT immunoreactive staining and expression of DAT mRNA in the substantia nigra,and the contents of dopamine and its metabolites in the striatum increased significantly(P0.05 or P0.01),while iron staining significantly decreased(P0.01).Conclusion Ginsenoside Rg1 could protect against the MPTP-induced neurotoxicity of dopaminergic neurons in PD mice by decreasing the MPTP-induced iron accumulation for inhibiting the oxidative stress reaction.