Local levels of interleukin-1beta, -4, -6 and tumor necrosis factor alpha in an experimental model of murine osteomyelitis due to staphylococcus aureus.

The purpose of this study is to evaluate local levels of interleukin-1 beta (IL-1 beta), -4 (IL-4), -6 (IL-6), and tumour necrosis factor-alpha (TNF-alpha), in a model of murine osteomyelitis due to Staphylococcus aureus. Cytokine levels in supernatants derived from bone homogenates were determined by enzyme-linked immunosorbent assay, for 28 days following the direct implantation of murine tibiae with S.aureus. Levels of IL-1 beta and IL-6 in infected bone were elevated in the early post-infection period and then decreased. In contrast, TNF-alpha levels remained elevated 3 to 28 days post-infection, while IL-4 levels were elevated late in the course of infection. The histopathology of infected bone showed predominant infiltration of inflammatory cells and bone resorption 3 to 7 days after infection, and bone resorption and adjacent areas of formation 14 to 28 days after infection. These results suggest that the elevated IL-1 beta and IL-6 levels induced by infection may be related to bone damage mainly in the early phase of infection, and that TNF-alpha and IL-4 may at least in part be associated with histopathological changes, including both bone resorption and formation in the later phase of this osteomyelitis model.

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)-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) 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 roxithromycin administration and a group not receiving roxithromycin. IL-1beta and TNF-alpha levels were significantly lower for the administration group after 7-14 days and after 21-28 days, respectively. 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-1beta and TNF-alpha, and may exhibit an anti-inflammatory effect in this osteomyelitis model.