Characterization of a polyacrylamide gel-induced granuloma in mice: involvement of arachidonate metabolites.

The injection of polyacrylamide gel (Bio Gel P-4, 200-400 mesh) into the subcutaneous area of mice, induced an inflammatory reaction which was characterized by the migration of leukocytes (mainly neutrophils) from the blood vessels towards the polyacrylamide gel. A rapid protein accumulation was observed during the migration of cells towards the inflamed site. Neutrophils released some pro-inflammatory lipids (prostaglandins, leukotriene B4) and lysozyme, these products were assayed in the granuloma exudate at various times of the granuloma formation. In our experimental inflammatory model, the results suggest that neutrophils that are attracted by the polyacrylamide gel produce eicosanoids and lysozyme, which could act synergistically to potentiate cell migration and protein accumulation in the inflamed site.