Abstract
BACKGROUND: Polyphenol catechins from green tea, particularly (-)-epigallocatechin-3-gallate (EGCG), exhibits numerous beneficial health effects, although the mechanisms remain unclear. METHODS: In this study, the mechanism of EGCG-mediated healing in an experimentally injured zebrafish model was examined at the cellular and molecular level using confocal microscopy and gene expression analysis. RESULTS: The mechanisms of action of EGCG were shown to involve: (1) reducing neutrophil response (accumulation, travel speed, and distance) and (2) downregulating the expression of IL-1β, TNFα, and related signaling pathways. As determined by dynamic time-lapse tracking studies, the local accumulation of neutrophils with high migration speeds after wounding (n=33 cells, v=0.020 μm/s, d=37.8 μm), underwent significant reduction following treatment with EGCG doses of 300 μM (n=22 cells, v=0.013 μm/s, d=39.5 μm) and 600 μM (n=18 cells, v=0.008 μm/s, d=9.53 μm). Reverse transcription polymerase chain reaction studies revealed that several signature genes in the IL-1β, TNFα, and related signaling pathways were downregulated after EGCG treatment. CONCLUSION: The convenience, transparency, and simplicity of the zebrafish model facilitate tracking of fluorescent neutrophils in real time, in order to monitor inflammation, and assess the impact of therapeutic agents.