Greeantea prevents Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

초록

Parkinson’s disease (PD) is an age-related neuro-degenerative disorder caused by loss of dopaminergic neurons in substantia nigra. In the experimental animal models, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been demsonstreated to produced PD by initial metabolism to 1-methyl-4-phenylpyridinium (MPP+) which overproduced superoxide anion (O2-) that can combine with nitric oxide (NO) to form the toxic peroxynitrite (ONOO-). Thus, inhibition of NO overproduction has shown to produce neuro-protective effect against PD caused by administration of MPTP. Green tea containing high level of (-)-epigallocatechin 3-gallate (EGCG), a flavonoid known to inhibit the expression of NOS, was administered to test whether EGCG attenuates the MPTP-induced PD in mice. Tea (5ml/day, drinking freely for 6 days) and 25mg/kg EGCG (oral injection for 6 days) prevented the MPTP (5days)-induced loss of tyrosine hydroxylase (TH)-positive cells in substantia nigra compacta. Administration of EGCG and tea prevented the loss of TH activity, the rate-limiting enzyme for dopamine production in striatum, from 21% of the control levels in MPTP treated mice up to 73.9% and 67.3%, respectively. In support of this, their treatments preserved the striatal dopamine levels from the MPTP induced depletion. This attenuation of dopamine depletion was caused by the EGCG dependent inhibition of NOS in substantia nigra. This study suggests that regular consumption of green tea may reduce the incidence of PD caused by environmental chemicals and contribute to the reduction of morbidity in later life.