Results from epidemiological studies indicated that there exists an inverse correlation between consumption of green tea and neurodegenerative diseases including Parkinson's disease. We hypothesized that consumption of green tea would activate endogenous protective mechanisms against environmental toxin-induced cell injury, which is believed to play a causative role in the etiology of Parkinson's disease. Here, we found that epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, concentration-dependently (1 microM, 3 microM and 10 microM) reduced dichlorodiphenyl-trichloroethane (DDT) (100 microM)-induced cell death in dopaminergic neuroblastoma SHSY-5Y cells. The cell viability was determined by trypan blue exclusion assays. We also found that preconditioning the SHSY-5Y cells with EGCG by multiple, brief, prior exposures of the cells to EGCG can subsequently protect the cells from DDT-induced cell death. The EGCG-induced protective effect positively correlated with the number of exposures to EGCG. These results suggest that EGCG has a protective effect against DDT-induced cell death, and that prior exposures to EGCG activate an endogenous protective mechanism in the dopaminergic cells which can mitigate organochlorine pesticide-induced cell injury.
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