Epicatechin gallate increases glutamate uptake and S100B secretion in C6 cell lineage

There is a current interest in dietary compounds, such as green tea polyphenols, that can favor protection against a variety of brain disorders, including Alzheimer's disease, ischemia, and stroke. The objective of the present study was to investigate the effects of (-)-epicatechin-3-gallate (ECG), one of three three major green tea antioxidants, on C6 lineage cells. Here, we evaluated cell morphology and integrity and specific astrocyte activities; glutamate uptake and secretion of S100B in the presence of 0.1, 1 and 10 microM ECG. During 6 h of incubation, cell morphology was altered only at 10 microM ECG; however, after 24 h of treatment, cells become stellate in the presence of all concentrations of ECG. Loss of cell integrity was observed after 24 h with 10 microM ECG and represented only 6% of cells, in contrast with 2% observed at basal conditions. ECG (1-10 microM) induced a decrease (about 36%) in glutamate uptake after 1 h of incubation. After 6 h, an opposite effect occurred and ECG induced a sustained increase in glutamate uptake of about 70% from 0.1 microM. In addition, a significant increase in S100B was observed at 1 microM ECG (36%) and 10 microM ECG (69%) after 1 h, in contrast to 6 h of treatment, where all doses of ECG induced a significant increase (about 60%) in S100B secretion. These data demonstrate that ECG induces a significant improvement in glutamate uptake and S100B secretion in C6 cells, indicating that ECG could contribute to the neuroprotective role of astroglial cells.