Inhibitory effect of roxithromycin on the local levels of bone-resorbing cytokines in an experimental model of murine osteomyelitis

Objectives: The purpose of this study was to evaluate the inhibitory effect of roxithromycin on the production of interleukin (IL)-1β, IL-6 and tumour necrosis factor-α (TNF-α) in a murine tibial osteomyelitis model using Staphylococcus aureus. Methods: Cytokine levels in supernatants derived from bone homogenates were measured by enzyme-linked immunosorbent assay for 28 days, after oral administration of roxithromycin at 5 mg/kg/day. Results: There was no significant difference in IL-6 levels between a group receiving roxithro- mycin administration and a group not receiving roxithromycin. IL-1β and TNF-α levels were significantly lower for the administration group after 7-14 days and after 21-28 days, respect- ively. However, a significant difference in bacterial counts in bone between the groups was not observed. Conclusion: These results indicate that roxithromycin suppresses the local expression of IL-1β and TNF-α, and may exhibit an anti-inflammatory effect in this osteomyelitis model.