Resveratrol treatment attenuates the wound-induced inflammation in zebrafish larvae through the suppression of myeloperoxidase expression

Resveratrol, a polyphenolic phytoalexin found in many plants, was reported to exhibit anti-inflammatory effects, but its molecular mechanism is not fully understood. This study was aimed to investigate the anti-inflammatory effects of resveratrol in vivo using a zebrafish model of wound-induced inflammation. Caudal fin-wounded zebrafish larvae were treated with resveratrol for 8 h. Neutrophil recruitment was visualized in transgenic line "Tg (mpx: GFP)" expressing GFP-tagged neutrophil-specific myeloperoxidase (mpx). The enzymatic activity of Mpx was evaluated by histochemical staining. Relative mRNA levels of mpx and cyclooxegenase-2 (cox2) were quantified by qRT-PCR, and the protein expression levels of Mpx and Cox2 were detected by immunostaining. Results showed that wound-induced neutrophil recruitment in zebrafish was not affected by resveratrol, but Mpx enzymatic activity in zebrafish was significantly suppressed by resveratrol in a dose-dependent manner. Moreover, both mRNA and protein expression levels of Mpx and Cox2 were significantly down-regulated by resveratrol. Taken together, our results provide in vivo evidence that the anti-inflammatory effects of resveratrol on wound-induced inflammation are significantly mediated through the suppression of Mpx and Cox2 at both transcriptional and protein levels, rather than the down-regulation of neutrophil recruitment. In conclusion, this in vivo zebrafish model can be readily applied to screen other potential anti-inflammatory compounds at a whole-organism level.