In vitro study of human alveolar macrophages inflammatory mediator transcriptions and releases induced by soot FR 101, Printex 90, titandioxide and Chrysotile B.

Soot FR 101, Printex 90 and Chrysotile B are frequently found in indoor air pollutants phagocytized by alveolar macrophages (AM) involved in inflammatory pulmonary processes as, e.g. in cytokine secretions. The transcription factor NF-kappaB has a role in the trans-duction pathway of proinflammatory cytokines like IL-1beta, IL-6 and TNF-alpha. We therefore investigated whether the transcription factor NF-kappaB and subsequent inflammatory cytokine secretions by AM are induced by exposure to these particles compared to the inert TiO2. AM were incubated for 90 min at particle concentrations of up to 100 microg/10(6) cells. Sequential reverse transcription and semiquantitative cDNA amplification (RT-PCR) was used to measure NF-kappaB and cytokine mRNA expressions. Compared to control exposures these particles induced an up to 4.6-fold increase in gene expression of the transcription factor NF-kappaB (p < 0.01), resulting in up to 12.9-fold enhanced transcription rates of IL-1beta, IL-6 and TNF-alpha (p <0.05). The particles and fibre dependent increases in mRNA reached maximum levels at 90 min post exposure. After an exposure time of 8 hrs, IL-1beta, IL-6 and TNF-alpha proteins, measured by enzyme-linked immunosorbent assays (ELISA), were significant elevated in supernatants of AM, revealing an up to 30.5-fold increase in TNF-alpha secretion rates (p <0.01). Our results suggest that exposure of human AM to soot FR 101, Printex 90, TiO2 and Chrysotile B induce the transcription and production of proinflammatory cytokines via NF-kappaB and may play an important role in the pathogenesis of airway disease and lung parenchymal injury.