Airway region-specific effects of carbon black nanoparticles (CBNP)

CBNP are present in industrially produced carbon black used for reinforcement of elastomers (e.g. in tyres) but also for paints, toner and batteries. CBNP may have lung cytotoxic and pro-inflammatory effects.

The commercially available CBNP Printex 90 (P90) was shown to possess cytotoxic and pro-inflammatory properties in mice and human epithelial cell lines. We sought to investigate whether these particles exert similar effects in distal versus proximal airway explants of mice. Further, we aim to investigate whether surface modifications on CBNP can lead to increase or decrease in their biological effects.

The impact of CBNP on different airway regions was assessed by microdissection of proximal and distal airways from mouse lungs and ex vivo stimulation for 0.5 – 48 hours. Cytotoxicity was measured by LDH release and cytokine mRNA expression by qRT-PCR.

Our study could not show any cytotoxic effects on microdissected airways after incubation with Printex 90 or acetylene soot which displays PAHs on its surface. Interestingly, the pro-inflammatory cytokine IL-6 (mRNA) was upregulated after 4h of exposure to either particles but only in proximal airways. IL-1 β, KC and TNF α mRNA expression remained unchanged in mice and epithelial cell lines.

Although our results do not show significant cytotoxic effects of P90 and acetylene soot on proximal and distal airways, this does not exclude that oxidative stress, apoptosis or proliferation of airway cells are affected by P90 or acetylene soot. Apart from looking into these other parameters, other chemically modified CBNP will be analysed to reveal the impact of other functional surface groups (9-nitroantracene, benzo(a)pyrene) on the particle's toxicological properties.

Supported by the BMBF: joint project Carbon Black (03X0093A)