Assessment of 2-Pentadecyl-2-oxazoline Role on Lipopolysaccharide-Induced Inflammation on Early Stage Development of Zebrafish (Danio rerio)

Abstract

Lipopolysaccharide (LPS), or bacterial endotoxin, is an important virulence factor in several human and animal pathologies. Oxazoline of Palmitoylethanolamide (PEAOXA) has shown strong anti-inflammatory activity in several animal models. LPS was applied for 24 h to zebrafish embryos to induce inflammation, and then the anti-inflammatory action of PEAOXA was evaluated for the first time in the zebrafish model (Danio rerio). Different concentrations of PEAOXA were tested for toxicity on zebrafish embryonic development; only the highest concentration of 30 mg/L showed toxic effects. Quantitative RT-PCR was applied to detect Tumor necrosis factor-α, Interleukin 1β, 6, and 8, and members of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). Exposure to LPS induced an increase in pro-inflammatory cytokines (tumor necrosis factor and interleukin 1, 6, and 8) in both gene and protein expression, as well as an increase of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the nuclear factor kappa light polypeptide enhancer in B-cells inhibitor (IκBα) gene expression. Furthermore, acute LPS exposure also induced an increase in tryptase release, related to mast cell activity, and in the production of apoptosis-related proteins (caspase 3, bax, and bcl-2). Treatment with PEAOXA 10 mg/L significantly counteracts LPS-induced inflammation in terms of cytokine expression and decreases tryptase release and the apoptosis pathway.