Early cartilage degradation in cationic immune complex arthritis in mice : relative role of interleukin 1, the polymorphonuclear cell (PMN) and PMN elastase

Objective. To determine the relative role of interleukin 1 (IL-1), polymorpbonuclear cell (PMN) and PMN elastase in early cartilage degradation in cationic immune complex mediated arthritis (ICA) in mice. ICA is characterized by early production of IL-1, pronounced influx of PMN and marked cartilage degradation within one day. Methods. IL-1 was neutralized by polyclonal antibodies against IL-1α and IL-1β, given shortly before arthritis induction. The role of PMN was studied in mice made neutropenic by whole body irradiation (750 rad). The effect of elastase was examined in beige mice with PMN deficient in elastase. Results. Neutralizing IL-1 during arthritis induction reduced PMN infiltration significantly and diminished cartilage degradation by 50%