Evaluation of the dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to chrysotile or crocidolite asbestos in a 28-day quantitative inhalation toxicology study

• Published in: Toxicology and applied pharmacology 2018-07, Vol.351, p.74-92
• Main Authors: Bernstein, D.M., Toth, B., Rogers, R.A., Sepulveda, R., Kunzendorf, P., Phillips, J.I., Ernst, H.
• Format: Article
• Language: English
• Subjects: Animals; Asbestos, Crocidolite - administration & dosage; Asbestos, Crocidolite - toxicity; Asbestos, Serpentine - administration & dosage; Asbestos, Serpentine - toxicity; Dose-Response Relationship, Drug; Dust; Inhalation Exposure - adverse effects; Lung - drug effects; Particle Size; Pleura - drug effects; Rats; Time Factors
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2018.04.033

This study provides an understanding of the biokinetics and potential toxicology in the lung and pleura following inhalation of brake-dust (brakes manufactured with chrysotile). The design included a 28-day repeated multi-dose inhalation exposure (6 h/d, 5 d/wk, 4 wks) followed by 28-days without exposure. Fiber control groups included a similar grade chrysotile as used in the brakes and a commercial crocidolite asbestos. Aerosol fiber distributions of the chrysotile and crocidolite were similar (fiber-length > 20 μm/cm3: Chrysotile-low/high 42/62; Crocidolite-low/high 36/55; WHO-fibers/cm3: Chrysotile-low/high 192/219; Crocidolite-low/high 211/255). The total number of aerosol particles/cm3 in the brake-dust was similar to that in the chrysotile (Brake-dust 710–1065; Chrysotile 532–1442). Brake-dust at particle exposure levels equal to or greater than chrysotile or crocidolite caused no indication of microgranulomas, epithelial hyperplasia, or fibrosis (Wagner score