Periarticular tissue levels of cytokine- and endothelin-1-like immunoreactivity during the course of antigen-induced arthritis in the rat

Abstract.

Objective and Design: To correlate the changes in periarticular tissue levels of pro-inflammatory cytokines and endothelin-1 (ET-1) to local pathophysiology in rats with antigen-induced arthritis (AIA).¶Materials: The periarticular soft tissue was excised from sixty-six rats at different stages of AIA.¶Methods: The samples were homogenized and the levels of immune like (LI) reactivities were determined. The levels in the arthritic joints were compared to those in non-arthritic tissue. Statistical significance was determined by ANOVA followed by Fisher PLSD.¶Results: Compatible with a role in an early alarm reaction some mediators (tumor necrosis factor α-LI, interleukin-2-LI and interferon-γ-LI) were elevated prior to the vascular inflammatory activity. The curve for ET-1-LI closely followed the intensity of the inflammation whereas these parameters preceeded the elevation of interleukin-1β-LI.¶Conclusions: Transient waves of different mediators appear during the course of the arthritis. This indicates the presence of active downregulatory mechanisms. Here the model could differ from human rheumatoid arthritis.