The effect of surface modification of particles on MIP-2 release, TNF-α release and apoptosis. A) MIP-2 release, B) TNF-α release and C) Apoptosis. Hornfels-2 and quartz-2 particles were treated in the absence or presence of aluminium lactate as described in Materials and Methods, and thereafter added to the cultured macrophages for 20 h. The MIP-2 and TNF-α release were analysed by ELISA, and apoptosis by flow cytometry after Hoechst 333258 staining. The results represent the mean +/- SEM of 3–5 independent experiments. *Significant reduction in MIP-2 release in aluminium lactate-coated versus non-coated hornfels-2 particles (p ≤ 0.05).