Cytotoxicity and anaphase aberrations induced by mineral fibres in cultured human mesothelial cells

Our plain-English summary of Cytotoxicity and anaphase aberrations induced by mineral fibres in cultured human mesothelial cells, by K. Pelin, K. Husgafvel-Pursiainen, M. Vallas, et al (Toxicology in Vitro, 1992).

The study

• Authors: K. Pelin, K. Husgafvel-Pursiainen, M. Vallas, E. Vanhala, K. Linnainmaa
• Journal: Toxicology in Vitro
• Published: 1992;6(5):445-50
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The in vitro cytotoxicity of two amphibole asbestos fibres (amosite and crocidolite), a serpentine asbestos (chrysotile), a non-asbestos fibrous aluminosilicate (erionite) and three different size fractions of both glass wool and rock wool fibres were assessed in an immortalized human mesothelial cell line, MeT-5A. We also investigated the induction of anaphase aberrations by the asbestos and erionite fibres. On a comparison by weight, amosite, crocidolite and chrysotile showed similar toxic effects (2-5 mug/cm(2) of the asbestos fibres caused 50% of cells to die) but erionite was less toxic (10-20 mug/cm(2) was needed for the same effect). When the doses were converted to the number of fibres/cm(2) of culture area, amosite was shown to be about 10 times more cytotoxic than crocidolite and chrysotile. Crocidolite and chrysotile showed similar cytotoxicity, and erionite was again less toxic. Of the man-made mineral fibres (MMMF), thin glass wool was the most cytotoxic (50% cell death for 10-20 mug/cm(2)), followed (in descending order of cytotoxicity) by thin rock wool, coarse glass wool, milled rock wool, milled glass wool and coarse rock wool. In general, the MMMF samples were less toxic than the asbestos and erionite samples. All three asbestos types studied induced anaphase aberrations at high (near toxic) doses. A statistically significant increase in the number of aberrant anaphases was observed in cultures treated with crocidolite or chrysotile at 5 mug/cm(2). The increase was caused by lagging chromatids, chromosomes or chromosome fragments.

In plain English

This laboratory study exposed an immortalized, non-tumour-forming human mesothelial cell line (MeT-5A) to mineral fibres. The fibres were amosite, crocidolite and chrysotile asbestos, erionite, and three size fractions each of glass wool and rock wool. By weight, the three asbestos types were similarly toxic, with 2 to 5 micrograms per square centimetre killing half the cells; erionite needed 10 to 20. Counted by number of fibres, amosite was about 10 times more toxic than crocidolite and chrysotile. Glass wool and rock wool were less toxic by weight; thin glass wool was the most toxic. At 5 micrograms per square centimetre, a toxic dose with under 40% cell survival, crocidolite and chrysotile significantly increased abnormal cell divisions (anaphase aberrations): 29.7% and 36.7% of scored anaphases, against 19.0% in controls. Amosite and erionite produced no statistically significant increase, although the amosite increase at 5 micrograms per square centimetre was described as approaching significance. The authors concluded that the fibres themselves, particularly long thin fibres, are responsible for the cell damage. They judged that non-fibrous particles likely added to the glass wool and rock wool samples' toxicity.

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: Laboratory (in vitro) experiment on cultured human cells, measuring cell death and abnormal cell divisions (anaphase aberrations)
• Who was studied: An immortalized, non-tumorigenic human mesothelial cell line, MeT-5A, studied at the Institute of Occupational Health, Helsinki, Finland. No people were studied.
• Exposure: The fibres were UICC standard amosite and crocidolite (amphibole asbestos), UICC chrysotile A (Rhodesian, serpentine asbestos), Oregon erionite, and 'coarse', 'thin' and 'milled' fractions of glass wool and rock wool. Doses were measured in micrograms per square centimetre of culture area. Anaphase aberrations were tested only for the asbestos fibres and erionite.
• Main results:
  • Compared by weight, amosite, crocidolite and chrysotile were similarly toxic: 2 to 5 micrograms per square centimetre killed 50% of cells. Erionite was less toxic, needing 10 to 20 micrograms per square centimetre for the same effect.
  • When doses were expressed as number of fibres per unit of culture area, amosite was about 10 times more cytotoxic than crocidolite and chrysotile. Erionite was still less toxic than any of the asbestos fibres.
  • Among the glass wool and rock wool samples, thin glass wool was the most cytotoxic, followed by thin rock wool, coarse glass wool, milled rock wool, milled glass wool and coarse rock wool. These samples were less toxic by weight than the asbestos samples.
  • At the highest dose (5 micrograms per square centimetre, a toxic dose with less than 40% cell survival), total aberrant anaphases were significantly increased in cultures treated with crocidolite (29.7%, 64 cells analysed, P less than 0.01) and chrysotile (36.7%, 60 cells analysed, P less than 0.001). Controls had 19.0% (300 cells analysed). The increase was due to lagging chromatin material.
  • No statistically significant increase in aberrant anaphases was seen with amosite or erionite. At 5 micrograms per square centimetre, amosite produced an increase described as approaching statistical significance.
  • Only the toxic dose of asbestos fibres (less than 40% cell survival) induced aberrant anaphases.
• The authors' conclusion: The authors concluded that, in human cells too, the fibres themselves, and particularly long thin fibres, are responsible for the cell-damaging effects of mineral fibre samples.
• Limitations the authors state:
  • The glass wool and rock wool samples contained many non-fibrous particles. The authors judged it likely that these particles contributed to the samples' overall toxicity.
  • Because of the high proportion of non-fibrous particles, doses of glass wool and rock wool were not expressed as number of fibres per unit of culture area.
  • The authors suggested that the lack of effect of erionite on anaphases might be explained by the high proportion of non-fibrous particles in the erionite sample.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Amphibole Asbestos, Amosite, Crocidolite, Serpentine Group, Chrysotile, erionite.

Related studies

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• Specificity of asbestos-induced chromosomal aberrations in short-term cultured human mesothelial cells — K. Olofsson, J. Mark (1989)
• Cytotoxicity of oxidants and asbestos fibers in cultured human mesothelial cells — V.L. Kinnula, K. Aalto, et al. (1994)
• Studies on the role of oxygen radicals in asbestos-induced cytopathology of cultured human lung mesothelial cells — E.W. Gabrielson, G.M. Rosen, et al. (1986)
• Effects of asbestos and man-made vitreous fibers on cell division in cultured human mesothelial cells in comparison to rodent cells — K. Pelin, P. Kivipensas, et al. (1995)
• Cytogenetic response to asbestos fibers in cultured human primary mesothelial cells from 10 different donors — K. Pelin, A. Hirvonen, et al. (1995)

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