Effects of intraarticular glucocorticoids on macrophage infiltration and mediators of joint damage in osteoarthritis synovial membranes: Findings in a double‐blind, placebo‐controlled study

Objective To investigate the effects of intraarticular glucocorticoid treatment on macrophage infiltration, the expression of the chemokines monocyte chemoattractant protein 1 (MCP‐1) and macrophage inflammatory protein 1α (MIP‐1α), and the expression of matrix metalloproteinases 1 and 3 (MMPs 1 and 3) and their inhibitors, the tissue inhibitors of metalloproteinases 1 and 2 (TIMPs 1 and 2), in osteoarthritis (OA) synovial membranes. Methods Forty patients underwent arthroscopic biopsy before and 1 month after intraarticular injection of glucocorticoids. Twenty‐one patients received 120 mg of methylprednisolone acetate (Depo‐Medrol; Upjohn, Kalamazoo, MI), and 20 patients received placebo (1 patient received placebo in 1 knee and methylprednisolone acetate in the other). Immunoperoxidase staining for the expression of CD68, MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 was performed, and the immunostaining was quantified by color video image analysis. Results CD68, MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 immunostaining was observed in all synovial membranes. Intraarticular glucocorticoid treatment was associated with a small (30%) but statistically significant (P = 0.048) reduction in CD68+ macrophage staining in the synovial lining layer, but there was no change in the CD68 expression in the synovial sublining layer. No significant differences were observed for MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 immunostaining in the synovial lining or sublining layers. Conclusion Intraarticular glucocorticoids may reduce CD68+ macrophage infiltration into the synovial lining layer, but not the expression of MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 in the synovial membrane, in patients with OA.