The effect of (-)-epigallocatechin 3-gallate (EGCG), a major polyphenol of green tea, on neutrophil migration has been studied using multiwell-type Boyden chambers in vitro and a fluorescein isothiocyanate-labeled ovalbumin (FITC-OVA)-induced rat allergic inflammation model in vivo. EGCG inhibited rat neutrophil chemotaxis toward cytokine-induced neutrophil chemoattractant-1 (CINC-1) in a concentration-dependent manner. In addition, CINC-1-induced neutrophil chemotaxis was suppressed by the pretreatment of rat neutrophils with EGCG at the concentration over 15 microg/mL. EGCG caused concentration-dependent suppression of the transient increase in CINC-1-induced intracellular free calcium level in both rat neutrophils and rat CXC chemokine receptor 2 (CXCR2)-transfected HEK 293 cells. EGCG inhibited CINC-1 production by IL-1beta-stimulated rat fibroblasts (NRK-49F cells) and lipopolysaccharide-stimulated rat macrophages at the concentration over 50 microg/mL, a comparatively high concentration. Oral administration of EGCG (1.0 mg or 1.5 mg/rat) at 1 h before the challenge with FITC-OVA suppressed neutrophil infiltration into the air pouch (inflammatory site) in the air-pouch type FITC-OVA-induced allergic inflammation in rats. Chemokine levels in the pouch fluids, however, were not influenced by EGCG administration. The results suggest that EGCG suppressed neutrophil infiltration by a direct action on neutrophils, but not by indirect actions, including the suppression of chemokine production at the inflammatory site.
Fibroblasts play a critical role in chronic inflammation and wound healing. In this study, a fibroblast growthstimulating factor was purified from the exudate of carrageenan-induced inflammation in rats. The purified protein was a disulfide-linked homodimer. Amino acid sequence analysis of the peptides generated by cleavage with cyanogen bromide and proteinase V8 resulted in identification of the protein as S100A9. Recombinant S100A9 as well as its disulfide-linked homodimer stimulated the proliferation of fibroblasts at a similar concentration of the purified protein. The concentration of S100A9 in the exudate was determined by immunoblot analysis. The total protein concentration in the exudate reached a maximum 4 days after carrageenan injection and then slightly decreased, whereas the concentration of S100A9 reached a maximum at day 3 and then decreased rapidly. These studies show that S100A9 is present at a high concentration in the exudate of carrageenan-induced inflammation in rats, and that S100A9 stimulates proliferation of fibroblasts, suggesting that it plays a role in chronic inflammation.
Our results suggest that CINC-2, a novel rat CXC chemokine and CINC-3 play an important role in neutrophil recruitment in the rat air pouch/LPS-induced inflammation.
Background: Recently we demonstrated that activated rat macrophages produced neutrophil chemotactic factors (chemokines) including cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2α, CINC-2β, CINC-3/rat macrophage inflammatory protein (MIP)-2 and rat MIP-1α (rMIP-1α). Methods: In the present study, by using an enzyme-linked immunosorbent assay specific for each chemokine, we determined the levels of the chemokines in the pouch fluid (inflammatory site) of the fluorescein isothiocyanate-labeled ovalbumin (FITC-OVA)-induced allergic inflammation in rats. Effects of anti-chemokine antibodies on neutrophil chemotaxis were determined in vivo and in vitro. Results: CINC-1 was the major chemokine which rapidly increased after challenge with FITC-OVA, whereas CINC-3 was a minor one, and CINC-2, CINC-3 and rMIP-1α increased slowly with a lag time of about 2 h. Anti-CINC-1/CINC-2 antibodies, which inhibited all the CINCs, suppressed both neutrophil infiltration in vivo and neutrophil chemotactic activity of the 8-hour pouch fluid in vitro, whereas anti-rMIP-1α antibody slightly suppressed the chemotaxis in vivo and in vitro. Conclusion: Our results suggest that CINCs, especially CINC-1 and CINC-2, play an important role in the infiltration of neutrophils into the inflammatory site of FITC-OVA-induced allergic inflammation in rats.
Five striking and prey capture events of two goblin sharks were videotaped at sea for the first time, showing their extraordinary biting process. The goblin sharks swung their lower jaw downward and backward to attain a huge gape and then rapidly protruded the jaws forward a considerable distance. The jaws were projected at a maximum velocity of 3.1 m/s to 8.6–9.4% of the total length of the shark, which is by far the fastest and greatest jaw protrusion among sharks. While the jaws were being retracted, the mouth opened and closed again, which was considered a novel feeding event for sharks. Phylogenetic evidence suggested that their feeding behavior has evolved as an adaptation to food-poor deep-sea environments, possibly as a trade-off for the loss of strong swimming ability.
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