| Abstract
| - Objectives. To investigate the role of macrophages in the pathogenesis of chronic streptococcal cell wall (SCW)-induced arthritis using liposomal clodronate. Methods. Female Lewis rats with SCW-induced arthritis received a single intravenous injection of 20 mg of clodronate encapsulated within small unilamellar vesicles (SUVc) 10 days post-arthritis induction. Results. SUVc significantly suppressed the development of chronic SCW-induced arthritis for up to 26 days after treatment. At this time point, ED1+ macrophages were significantly depleted in the liver and ankle joints, although splenic macrophage numbers were not significantly different from control groups. Macrophage elimination induced a significant reduction in local levels of interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNFα) and matrix metalloproteinase-9 (MMP-9) from ankle joints. Conclusions. Macrophage elimination by SUVc inhibits local production of IL-1β, IL-6, TNFα and MMP-9, and the pathogenesis of inflammatory arthritis.
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