The effect of adjuvant arthritis on the subsequent local inflammatory response in rats

An assessment was made of the cellular inflammatory response to the subcutaneous implantation of sterile nitrocellulose discs and polyvinyl sponges in both normal rats and rats with adjuvant-induced arthritis. It was found that from 3 days after adjuvant injection the treated animals exhibited a reduced accumulation of inflammatory cells onto the nitrocellulose discs and that this impairment in response was not apparent until the discs had been retained for longer than 24 h. When discs were implanted after non-arthritogenic doses of adjuvant constituents or injection of brewer's yeast no effect was seen on the subsequent response. When polyvinyl sponges were used in adjuvant-treated animals a similar initial reduction in cellular accumulation was observed, which was later followed by increased cell numbers associated with enhanced granuloma formation. Differential cell counts revealed that both neutrophil and mononuclear cell types were affected. Some of the possible mechanisms involved in these observations are discussed.