Fibrogenic effect of wollastonite compared with asbestos dust and dusts containing quartz

Our plain-English summary of Fibrogenic effect of wollastonite compared with asbestos dust and dusts containing quartz, by M. Cambelová, A. Juck (Occupational and Environmental Medicine, 1994).

The study

• Authors: M. Cambelová, A. Juck
• Journal: Occupational and Environmental Medicine
• Published: 1994;51(5):343-6
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The distribution of length and diameter and the aspect ratio of crocidolite asbestos, a mineral substitute for asbestos (wollastonite), a manmade mineral fibre (glass wool), and synthetic fibres (polypropylene and polyacrylonitrite) were determined by light microscopy with phase contrast and, for crocidolite, also with transmission electron microscopy. The synthetic organic fibres and manmade mineral fibre used were of a size exceeding that considered respirable. Respirable materials were given to rats by the intratracheal method and after exposure for a standard time interval the main indices of fibrogenic effects--the total hydroxyproline content, the wet weight of the lung, and the total lipid content in the lung--were estimated. For wollastonite there was a significant increase in these variables in comparison with the controls. The fibrogenicity was considerably less than that of crocidolite and quartz.

In plain English

This was an animal experiment from Slovakia. The authors measured fibre length, diameter and aspect ratio for crocidolite asbestos, two wollastonite samples (a mineral asbestos substitute), glass fibre, and the synthetic fibres polypropylene and polyacrylonitrile. The glass fibre and both synthetic fibres were too large to reach the deep lung (not respirable). Male Wistar rats, about 18 per group, were given 25 mg of crocidolite, wollastonite, quartz or magnesite mine dust directly into the windpipe. Their lungs were examined after three months. Lung hydroxyproline, the main indicator of scarring (fibrogenicity), rose significantly with crocidolite and, less markedly, with wollastonite and mine dust. Lung wet weight showed similar results. The article words the wollastonite-crocidolite comparison differently in different places. The abstract calls wollastonite considerably less fibrogenic than crocidolite and quartz. The discussion says the more respirable wollastonite sample was less fibrogenic than quartz but comparable with crocidolite. The crocidolite fibres were short (mean length 4.42 micrometres). The authors concluded that wollastonite is not wholly inert and needs further research. They noted this short-term test could not assess cancer risk.

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: measurement of fibre dimensions plus intratracheal administration of dusts to rats, with lung fibrosis markers measured after three months
• Who was studied: Specific pathogen free male Wistar rats, about 300 g body weight, about 18 animals per group (total number not stated); dates not given
• Exposure: A single gravimetric dose of 25 mg in 1 ml of saline, given intratracheally, of crocidolite asbestos, wollastonite, standard quartz (high-fibrogenic comparison) or magnesite mine dust (low-fibrogenic comparison), compared with controls. Exposure lasted three months. Glass fibre, polypropylene and polyacrylonitrile were measured but were not respirable.
• Main results:
  • The glass fibre and the two synthetic organic fibres (polypropylene, polyacrylonitrile) were not respirable; the other samples were respirable. The article discusses respirability in terms of fibres reaching the alveolar spaces of the lung.
  • The crocidolite used had a mean length of 4.42 micrometres, and only 10% of its fibres were longer than 8 micrometres. The wollastonite (China) sample had an average length of 12.91 micrometres, diameter 1.57 micrometres and aspect ratio 11.88.
  • Lung hydroxyproline content, the main indicator of fibrogenicity, was increased significantly by crocidolite, and less markedly by wollastonite and by the magnesite mine dust.
  • Lung wet weight showed results similar to hydroxyproline.
  • Total lung lipid content was similar for crocidolite and wollastonite. The authors said lipid content was not a determining factor for fibrogenicity in this short-term study.
  • In the discussion, the more respirable of the two wollastonite samples was described as the more fibrogenic one, with fibrogenicity lower than quartz but comparable with crocidolite. The article's abstract, speaking of wollastonite generally, says its fibrogenicity was considerably less than that of crocidolite and quartz.
• The authors' conclusion: The authors concluded that wollastonite turned out not to be wholly inert and that further research on its biological effects is needed. They said synthetic organic fibres used in Slovakia, being non-respirable, are not supposed to present a health risk from the point of view of fibrogenicity.
• Limitations the authors state:
  • The experiment does not shed light on possible carcinogenic effects. The authors cite the view that short-term assays cannot accurately assess carcinogenic potential.
  • The crocidolite fibres were relatively short, which the authors say must be considered when judging its fibrogenicity.
  • Dosing by number of particles would have been imprecise because of differing particle sizes, so a weight-based dose was used.

Topics

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

Medical terms in this study, explained in our Lexicon: Fibrogenic, Wollastonite, Aspect Ratio (Length-to-diameter ratio), Crocidolite, Transmission Electron Microscopy (TEM).

Related studies

• Fibrogenic effect of wollastonite compared with asbestos dust and dusts containing quartz — E.E. McConnell (1995)
• Investigation of the biodurability of wollastonite and xonotlite — B. Bellmann, H. Muhle (1994)
• Mesothelial cell proliferation and biopersistence of wollastonite and crocidolite asbestos fibers — J.L. Macdonald, A.B. Kane (1997)
• Pulmonary toxicity of wollastonite in vivo and in vitro — E. Tátrai, Z. Kováciková, et al. (2004)
• Investigation on the durability of man-made vitreous fibers in rat lungs — B. Bellmann, H. Muhle, et al. (1994)
• Wollastonite exposure and lung fibrosis — M.S. Huuskonen, A. Tossavainen, et al. (1983)

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