Interaction of bioactive glasses with peritoneal macrophages and monocytes in vitro

Macrophage activation was analyzed following exposure to pure, crystalline a-quartz powders, two bioactive gel-glass powders of different compositions, and a melt-derived glass, 45S5 Bioglass((R)). The release of reactive oxygen metabolites (chemiluminescence test), modifications of cell morphology, the amount of tumor necrosis factor alpha (TNFalpha) secreted, and the amount of TNFa mRNA expression were evaluated. The 45S5 Bioglass((R)) powders elicited the highest chemiluminescence response while the two sol-gel glasses had a lower response with less of an oxidative burst difference between them. Particulate bioactive glasses are actively ingested by mouse peritoneal macrophages, and only the 58S sol-gel glass had a moderate toxic effect on the macrophages. Macrophage cell morphology showed increased size and cell spreading, consistent with the high level of cytokine secretion induced by 45S5 Bioglass((R)). The 45S5 Bioglass((R)) powders led to an increased release of TNFa and expression of TNFa mRNA relative to unstimulated and control treated monocytes. Bioactive glasses (and particularly 45S5 Bioglass((R))) that in vivo induce rapid bone growth appear to activate an autocrine-like process in which the response evoked by the material (for example monocyte and macrophage activation with cytokine production) enhances subsequent interactions with cells in contact with the material. (C) 2002 John Wiley & Sons, Inc. J Biomed Mater Res 60: 79-85,2002.