Short-term crocidolite inhalation studies in mice: validation of an inhalation chamber

Our plain-English summary of Short-term crocidolite inhalation studies in mice: validation of an inhalation chamber, by B. Rihn, E. Kauffer, P. Martin, et al (Toxicology, 1996).

The study

• Authors: B. Rihn, E. Kauffer, P. Martin, C. Coulais, M. Villa, M.C. Bottin, J.C. Vigneron, A. Edorh, N. Martinet
• Journal: Toxicology
• Published: 1996;109(2-3):147-56
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A nose-only inhalation chamber is described: this chamber being computer automated has been particularly designed for mice on which it was validated using a crocidolite aerosol at a nominal concentration of 13.6 mg/m3, 6 h/day during 5 days. A month later the mice showed typical inflammatory bronchoalveolar liquids with many polynucleated or activated macrophages and asbestos bodies. The burden of crocidolite fibers ranged from 345,000 to 1,300,000 fibers per mg of dried lung. This study demonstrates that during the month that followed a short-term mice exposure to crocidolite fibers, the inflammatory response was still persistent. These toxicological endpoints validate the nose-only inhalation chamber to be useful for common or transgenic mice.

In plain English

This was an animal experiment. The authors built a computer-controlled, nose-only inhalation chamber for mice and tested it with crocidolite asbestos. Fifteen male Balb/c mice breathed a crocidolite aerosol for 6 hours a day over 5 days, at a measured dust concentration that averaged 13.6 mg/m3. Five control mice were held in the same exposure tubes without crocidolite. The experiment ended four weeks after exposure stopped. At that point, the three exposed mice tested had 345 000 to 1 300 000 crocidolite fibers per mg of dried lung; the three controls tested had none. Fluid washed from the exposed mice's lungs contained more binucleated macrophages (4800 versus 600 per ml in controls) and more lymphocytes (20 100 versus 5600 per ml). Giant multinucleated macrophages appeared only in exposed mice. Levels of the inflammatory signal TNF-alpha did not rise. Exposed lungs showed inflammatory cells and asbestos bodies. The authors concluded that a relatively mild 5-day exposure produced a chronic inflammatory response and a high lung fiber burden one month later, and that the chamber was validated for mice.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment (short-term inhalation study in mice) used to validate a nose-only inhalation chamber
• Who was studied: Male Balb/c mice (printed as twenty seven-week-old mice). Fifteen were exposed and 5 were controls. Some analyses used fewer animals: fiber burden was measured in 3 treated and 3 control mice, and Table 2 lists 9 treated and 3 control.
• Exposure: Nose-only inhalation of crocidolite aerosol (a batch replacing the original UICC sample), 6 h/day for 5 days. Dust concentration was 10.8 to 16.0 mg/m3 (mean 13.6, plus or minus 2.1 mg/m3, n = 8). The mean concentration of fibers longer than 5 micrometres and thinner than 3 micrometres was 3594 (plus or minus 1142) fibers/ml.
• Main results:
  • About one month after exposure, the lung fiber burden in the three exposed mice measured was 361 to 1583 ng/mg, corresponding to 345 000 to 1 300 000 fibers per mg of dried lung. No fibers were found in the three control mice measured.
  • Binucleated alveolar macrophages in lung washings were 4800 (plus or minus 1100) per ml in exposed mice versus 600 (plus or minus 200) in controls. The authors reported this change as significant.
  • Total viable cells in lung washings were 118 000 (plus or minus 24 000) per ml in treated mice versus 93 000 (plus or minus 28 000) in controls. Table 2 marks this comparison with P greater than 0.05.
  • Giant multinucleated macrophages (800, plus or minus 400, per ml) were detected only in the crocidolite-exposed group.
  • Lymphocytes were higher in treated mice than in controls: 20 100 (plus or minus 8300) versus 5600 (plus or minus 300) per ml.
  • No increase in TNF-alpha was observed: 36.5 (plus or minus 23.9) U/mg in treated mice versus 43.2 (plus or minus 52.0) U/mg in controls.
  • Exposed mice showed perivascular and peribronchiolar inflammatory cells (Wagner scale value of 2) and asbestos bodies in terminal bronchioles. Control mice had no such changes.
• The authors' conclusion: The authors concluded that a relatively mild 5-day crocidolite exposure gave a chronic inflammatory response and a high fiber burden in mouse lungs 1 month later, and that the nose-only chamber was validated for use with common or transgenic mice.
• Limitations the authors state:
  • The authors noted that results in rodents are difficult to extrapolate to humans, because breathing patterns and airway branching differ.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Crocidolite.

Medical terms in this study, explained in our Lexicon: Crocidolite, Macrophage, Asbestos Bodies.

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