The development of glass-fibre bodies in the lungs of guinea-pigs

Our plain-English summary of The development of glass-fibre bodies in the lungs of guinea-pigs, 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;103(3):149-56
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Guinea-pigs were kept in an atmosphere that contained glass-fibre particles of submicron diameter. Much of the dust retained in the lung was later cleared in the bronchiolar debris as both extra- and intra-cellular fibres. Some fibres were uncoated 18 mth after inhalation.

The dust caused leakage of red cells from alveolar capillaries. Haemolysis of these cells was followed by the appearance of iron-containing material in alveolar macrophages.

Deposition of iron-containing material on intracellular glass fibres produced structures morphologically identical with asbestos bodies. These glass-fibre bodies also showed similar stages in their development, the original smooth coating becoming successively corrugated and beaded and finally separating into beads, so exposing the fibre which then fragmented.

The main difference lay in the timing of these changes, since coating of a glass fibre, its subsequent beading and fragmentation, were more rapid than with anthophyllite asbestos.

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

In plain English

This was an animal experiment. Eighteen male guinea-pigs breathed air with a high concentration of glass-fibre dust for 24 hours and were then killed at intervals up to 18 months later. Three unexposed control animals were also examined. Most of the dust fibres were thinner than one micrometre. The authors compared the lungs with those of guinea-pigs from their earlier study that had inhaled anthophyllite asbestos. Free glass fibres were cleared from the bronchioles (small airways) by one month, faster than anthophyllite. Within 48 hours, a thin iron-containing coating began forming on some glass fibres inside lung cells. The resulting "glass-fibre bodies" looked the same as asbestos bodies and passed through the same stages: smooth, corrugated, beaded, then fragmented. Fragmentation was first seen at 4 weeks, compared with 13 weeks for anthophyllite bodies. By 18 months most bodies were fragmenting. Animals killed at one month or later showed some thickening of the walls between air sacs, which rarely closed off the air spaces. Collagen increased little. The authors concluded that these changes were more rapid with glass fibre than with anthophyllite asbestos. They noted that the guinea-pig's short life-span made it impossible to tell whether the wall thickening was temporary.

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, with lung findings compared against guinea-pigs from the authors' earlier anthophyllite study
• Who was studied: 18 male guinea-pigs exposed to glass-fibre dust and killed at intervals up to 18 months after exposure, plus three control animals
• Exposure: Glass-fibre dust at high concentration for 24 hours, then no further exposure. Fibres were up to 0.5 mm long with a maximum diameter of 3.0 micrometres, though most were thinner than one micrometre.
• Main results:
  • In the exposed guinea-pigs, free glass fibres were completely cleared from the bronchioles by 1 month, faster than with anthophyllite.
  • Within 48 hours of exposure, a thin iron-staining (Perls-positive) coating appeared on some glass fibres inside lung cells.
  • Fragmentation of glass-fibre bodies was first seen in the animal killed at 4 weeks. Fragmenting anthophyllite bodies were first seen at 13 weeks.
  • At 18 months after exposure, most glass-fibre bodies were fragmenting.
  • Glass-fibre bodies were usually much shorter than asbestos bodies. The longest was 80 micrometres, compared with just over 100 micrometres for anthophyllite, and most were shorter than 30 micrometres.
  • All exposed animals killed at 1 month or later had some thickening of the walls between air sacs, but this rarely led to obliteration of the air spaces, unlike in anthophyllite-treated animals.
  • There was little general increase in collagen over time after exposure.
• The authors' conclusion: The authors concluded that iron-containing coatings on glass fibres produced structures morphologically identical to asbestos bodies, which went through the same developmental stages. They found that coating, beading and fragmentation happened more rapidly than with anthophyllite asbestos.
• Limitations the authors state:
  • Because of the guinea-pig's short life-span, the authors could not determine whether the thickening of the air-sac walls was transient.

Topics

Medical terms in this study, explained in our Lexicon: Alveolar Macrophage, Deposition, Asbestos Bodies, Anthophyllite.

Related studies

• Comparison of effects of glass fibre and glass powder on guinea-pig lungs — S.K. Botham, P.F. Holt (1973)
• Development of asbestos bodies on amosite, chrysotile and crocidolite fibres in guinea-pig lungs — S.K. Botham, P.F. Holt (1971)
• Asbestos-body formation in the lungs of rats and guinea-pigs after inhalation of anthophyllite — S.K. Botham, P.F. Holt (1972)
• 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)
• Formation of pseudo-asbestos bodies on sized glass fibres in the hamster lung — A. Holmes, A. Morgan, et al. (1983)
• The mechanism of formation of asbestos bodies — S.K. Botham, P.F. Holt (1968)

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