Epigallocatechin-3-gallate suppresses neutrophil migration speed in a transgenic zebrafish model accompanied by reduced inflammatory mediators

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-1 beta, TNF alpha, 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 mu m/s, d=37.8 mu m), underwent significant reduction following treatment with EGCG doses of 300 mu M (n=22 cells, v=0.013 mu m/s, d=39.5 mu m) and 600 mu M (n=18 cells, v=0.008 mu m/s, d=9.53 mu m). Reverse transcription polymerase chain reaction studies revealed that several signature genes in the IL-1 beta, TNF alpha, 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.