Development of asbestos bodies on amosite, chrysotile and crocidolite fibres in guinea-pig lungs

Our plain-English summary of Development of asbestos bodies on amosite, chrysotile and crocidolite fibres in guinea-pig lungs, by S.K. Botham, P.F. Holt (The Journal of Pathology, 1971).

The study

• Authors: S.K. Botham, P.F. Holt
• Journal: The Journal of Pathology
• Published: 1971;105(3):159-67
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

When amosite, chrysotile and crocidolite asbestos fibres were inhaled by guinea-pigs, the fibres were distributed throughout the lungs. Some fibres were ingested by macrophages, and Perls-positive material, apparently derived from red cells, was deposited on them. Other intracellular fibres remained uncoated during the year after dusting, but after a further 6 mth uncoated chrysotile fibres were not found; there were a few anthophyllite fibres but rather more crocidolite, whilst amosite fibres were still common. Both crocidolite and amosite fibres showing early stages in coating were common 18 mth after the dusts were inhaled.

The morphological development of asbestos body coating followed the sequence : smooth, corrugated, partially beaded, and fully beaded. Occasionally the asbestos body, if more than 20 µm in length, fragmented before being entirely beaded and the fragments were ingested by surrounding macrophages. These changes were similar to those previously seen following the inhalation of anthophyllite asbestos, but the rates of development differed, the changes being more rapid with chrysotile, slower with crocidolite and slower still with amosite, as determined by changes with time in the percentages of the various stages in the sequence of asbestos body development. There was no apparent morphological difference between asbestos bodies at the same stage of development although formed on different types of asbestos fibres.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was an animal experiment. Three groups of albino male guinea-pigs breathed air containing fine amosite, chrysotile or crocidolite asbestos dust for 24 hours in a dust tunnel. They were killed at intervals over the next 18 months. Animals that died during the study were discarded, and lung sections from the remaining 21 animals were stained with Perls' stain and examined under the microscope. The authors compared the results with anthophyllite from their earlier study. By one month, fibres inside cells had a coating of Perls-positive material, apparently derived from red cells, which formed asbestos bodies. For each animal, 100 asbestos bodies were sorted into five stages: smooth, corrugated, partly beaded, fully beaded and fragmenting. All fibre types followed this same sequence, and bodies at the same stage looked alike. The changes were most rapid with chrysotile, slower with crocidolite and slowest with amosite. By 18 months no uncoated chrysotile fibres were seen inside cells, while amosite and crocidolite fibres were still common. The authors suggested that chrysotile fibres could eventually be removed from the lungs. They noted that fragmenting bodies were probably undercounted.

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 inhalation experiment: a single 24-hour dust exposure followed by killing animals at intervals and microscopic examination of lung sections.
• Who was studied: Albino male guinea-pigs in three dust groups (amosite, chrysotile, crocidolite). Two animals died in each of the amosite and chrysotile groups and three in the crocidolite group, and these were discarded. Lungs of the remaining 21 animals were examined. Undusted control guinea-pigs were also examined, and comparisons were made with an anthophyllite group from the authors' earlier work.
• Exposure: 24 hours of inhalation of fine amosite, chrysotile or crocidolite dust in a dust tunnel (anthophyllite from the earlier study used for comparison).
• Main results:
  • By 1 month after exposure, a Perls-positive coating had formed on fibres inside cells, producing asbestos bodies.
  • The coating material appeared to come from red cells.
  • For each animal, 100 randomly selected asbestos bodies were classified into five forms. The coating developed in the sequence smooth, corrugated, partially beaded and fully beaded, with fragmentation as the final form.
  • Asbestos bodies on the different asbestos types looked similar at each stage.
  • The rate of asbestos-body development differed by fibre type: fastest with chrysotile, slower with crocidolite and slower still with amosite.
  • Removal of fibres lying outside cells appeared faster with chrysotile and crocidolite than with amosite and anthophyllite.
  • By 18 months no uncoated chrysotile fibres were seen inside cells.
  • At 18 months, amosite and crocidolite fibres inside cells were still common in the walls between air sacs, and some were embedded in the muscular coats of the bronchioles.
  • The authors suggested that chrysotile fibres could eventually be removed from the lungs.
• The authors' conclusion: The authors concluded that asbestos bodies on amosite, chrysotile and crocidolite followed the same developmental sequence as on anthophyllite, but at different rates.
• Limitations the authors state:
  • Counts of fragmenting asbestos bodies were probably too low, because entirely fragmented bodies were hard to recognise and could not be counted.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Amosite, Chrysotile, Crocidolite, Macrophage, Anthophyllite, Asbestos Body Formation.

Related studies

• The development of glass-fibre bodies in the lungs of guinea-pigs — S.K. Botham, P.F. Holt (1971)
• Comparison of effects of glass fibre and glass powder on guinea-pig lungs — S.K. Botham, P.F. Holt (1973)
• The effects of inhaled crocidolites from Transvaal and North-west Cape mines on the lungs of rats and guinea-pigs — S.K. Botham, P.F. Holt (1972)
• The mechanism of formation of asbestos bodies — S.K. Botham, P.F. Holt (1968)
• Asbestos-body formation in the lungs of rats and guinea-pigs after inhalation of anthophyllite — S.K. Botham, P.F. Holt (1972)
• Rapid short-term clearance of chrysotile compared with amosite asbestos in the guinea pig — A. Churg, J.L. Wright, et al. (1989)

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