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 1alpha (MIP-1alpha), 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.
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-1alpha, MMP-1, MMP-3, TIMP-1, and TIMP-2 was performed, and the immunostaining was quantified by color video image analysis.
CD68, MCP-1, MIP-1alpha, 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-1alpha, MMP-1, MMP-3, TIMP-1, and TIMP-2 immunostaining in the synovial lining or sublining layers.
Intraarticular glucocorticoids may reduce CD68+ macrophage infiltration into the synovial lining layer, but not the expression of MCP-1, MIP-1alpha, MMP-1, MMP-3, TIMP-1, and TIMP-2 in the synovial membrane, in patients with OA.