To investigate the regulated role of IL-1β in initiating and maintaining inflammation, PMA-differentiated THP-1 macrophages were exposed to two micro-sized crystalline silica particles (Si3-5μm and Si1μm) from 3h to 24h, respectively. Cytotoxicity and inflammatory cytokines (IL-1β, TNF-α and IL-6) expressions measured showed that they were induced by both silica particles in positive dose-dependent manners. The levels of inflammatory cytokines induced by Si1μm were higher than those induced by Si3-5μm at low concentration. When pretreated with anti-human IL-1β, not only the high levels of IL-1β but also elevated TNF-α and IL-6 induced by both silica particles were remarkably blocked, especially Si1μm particle. In addition, recombinant human IL-1β protein could induce macrophages to strikingly augment TNF-α and IL-6 expressions. Our data suggest that IL-1β could play a critical role of switching regulation in the downstream inflammation induced by micro-sized silica particles.
Keywords: IL-1β; Inflammatory cytokines; Macrophages; Silica particles.
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