Abrogation of the inflammatory response in LPS‐stimulated RAW 264.7 murine macrophages by Zn‐ and Cu‐doped bioactive sol–gel glasses

Abstract The attenuation of an in vitro inflammatory response in RAW 264.7 murine macrophages stimulated with lipopolysaccharide (LPS) endotoxin was tested using sol–gel‐derived bioactive glasses. Three general types of sol–gel‐derived samples were evaluated: 58S, zinc‐containing glasses, and copper‐containing glasses. Distinct experimental procedures were used to test the potential of bioactive glasses to attenuate the inflammatory response in three situations: (1) therapeutically following LPS stimulation, (2) prophylactically before LPS stimulation of macrophages, and (3) indirectly via the glass dissolution products after stimulation with LPS. A sandwich enzyme‐linked immunosorbent assay (ELISA) was used to monitor the concentration of tumor necrosis factor‐α (TNF‐α) secreted by macrophage cells. The strongest reduction in TNF‐α concentration was observed when macrophage cells were first incubated with bioactive glass powder and then stimulated with LPS. This suggests a possible prophylactic application of these bioactive glasses for the prevention of inflammation. The 58S glass was capable of reducing the expression of TNF‐α by macrophages, although the zinc‐ and copper‐containing were more effective at suppressing the inflammatory response. The additional benefit of using zinc‐ and copper‐doped bioactive glasses may be explained by the direct interactions of zinc and copper ions in key regulatory pathways for the inflammation response. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009