Acta Pharmacologica Sinica 2005 January; 26 (1): 56-62; doi: 10.1111/j.1745-7254.2005.00019.x

Aim: To investigate the effect of ginsenoside Rg1, an effective ingredient from ginsenoside, on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced substantia nigra neuron lesion.

Methods: C57-BL mice were given MPTP to prepare Parkinson disease mice model. Different doses of Rg1 (5, 10, and 20 mg·kg^-1·d^-1) or N-acetylcystein (NAC) (300 mg·kg^-1·d^-1) were given 3 d prior to MPTP in the pretreatment groups. Glutathione (GSH) level and total superoxide dismutase (T-SOD) activity in substantia nigra were determined by spectrophoto-metry. Nissl staining, tyrosine hydroxylase immunostaining, and TUNEL labeling were used to observe the damage and apoptosis of nigral neurons. Western blot analysis was used to detect the phospho-JNK and phospho-c-Jun levels in midbrain homogenates.

Results: Pretreatments of C57-BL mice with different doses of Rg1 or NAC were found to protect against MPTP-induced substantia nigra neurons loss. Rg1 or NAC prevented GSH reduction and T-SOD activation in substantia nigra, and attenuated the phosphorylations of JNK and c-Jun following MPTP treatment.

Conclusion: The antioxidant property of Rg1 along with the blocking of JNK signaling cascade might contribute to the neuroprotective effect of ginsenoside Rg1 against MPTP.