Abstract

Saponin has been known to be a major antioxidant component in panax ginseng. Recent experimental study suggests that some antioxidant materials prevent Parkinson's disease caused by 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) in an animal model. The present study was performed to demonstrate the effect of ginseng saponins in the Parkinson's disease model induced by MPTP. To verify the effect of ginseng saponin on dopaminergic neurons in the mice brain, the tyrosine hydroxylase-immunoreactive (TH-ir) neurons were observed by immunohistochemical stain and immunoelectron microscopy (preembedding method). Also, in order to estimate the immunoreactivity of dopaminergic neuropils, they were quantified by image analysis. The number of TH-ir neurons of substantia nigra was significantly increased in the high-dose (0.46 mg/kg) ginseng saponin group compared with the MPTP injected group. The immunoreactivity of TH-ir neuropils in striatum was significantly increased in both high and low-dose (0.1 mg/kg) ginseng saponin groups compared with the MPTP injected group. In immunoelectron microscopic observation, TH-ir neurons of the control and both ginseng saponin injected group showed normal nuclei and well preserved cytoplasmic organelles. In the MPTP injected group, dying dopaminergic neurons showed destroyed nuclei and cytoplasmic organelles. These results suggest that ginseng saponin has a protective effect on the Parkinson's disease model induced by MPTP.

• Keywords: Parkinson's disease;Tyrosine hydroxylase;Immunoelectron microscopy;Image analysis;Ginseng saponin