Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells

Our plain-English summary of Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells, by M.C. Jaurand, L. Kheuang, L. Magne, et al (Mutation Research, 1986).

The study

• Authors: M.C. Jaurand, L. Kheuang, L. Magne, J. Bignon
• Journal: Mutation Research
• Published: 1986;169(3):141-8
• Cited by: 70 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The induction of chromosomal aberrations in rat pleural mesothelial cells (RPMC) following in vitro treatment with chrysotile fibres has been demonstrated. The production of chromosomal aberrations was also observed after treatment of the cells with benzo-3,4-pyrene (BP). The yield of abnormal metaphases was dose-dependent and reached 58% at a BP dose of 2 micrograms/ml. Chrysotile fibres at 7 micrograms/ml induced 21% abnormal metaphases and the frequency decreased with further increases in fibre concentration. Their decline is possibly related to a lethal effect. Chrysotile-induced chromosomal aberrations were primarily of the chromatid type and included breaks and fragments. BP induced chromosome exchanges which were not seen following chrysotile treatment. Minutes and double minutes were detected in BP-treated RPMC and occasionally found after chrysotile application. These results confirm that chrysotile fibres are clastogenic for some cultured cells and demonstrate that the fibres induce chromosome damage in target RPMC.

In plain English

This was a laboratory experiment on rat pleural mesothelial cells grown in culture. The authors exposed the cells for 48 hours to Canadian chrysotile asbestos fibres at a range of concentrations, or to the chemical benzo-3,4-pyrene (BP) for comparison. They examined 100 dividing cells per treatment for chromosome damage. BP produced damage that rose with dose, reaching 58% abnormal cells at 2 micrograms per millilitre. Chrysotile also produced damage, at a lower yield than BP. At 7 micrograms per millilitre, 21% of cells were abnormal, and the proportion fell at higher concentrations. The authors thought this fall was probably related to the fibres' toxicity. Chrysotile damage was mainly of the chromatid type, with no chromatid exchanges. Chrysotile also reduced the proportion of cells with 42 chromosomes. The authors concluded that chrysotile fibres are clastogenic (cause chromosome breaks) and damage chromosomes in these target cells. They noted that the cells probably had undergone some spontaneous transformation in culture.

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) cell-culture experiment
• Who was studied: Rat pleural mesothelial cells (RPMC) from the parietal pleura, grown in culture and used between the 11th and 18th passage; 100 metaphases (dividing cells) examined per treatment
• Exposure: Canadian chrysotile fibres (1.9 x 10^7 fibres per microgram) supplied by the Société Nationale de l'Amiante, Sherbrooke, Quebec, added at various concentrations for 48 hours; benzo-3,4-pyrene (BP) used as a reference agent
• Main results:
  • In BP-treated cells, abnormal metaphases increased with dose and reached 58% at 2 micrograms per ml
  • Chrysotile also induced chromosome abnormalities, but at a lower yield than BP
  • In chrysotile-treated cells, 7 micrograms per ml produced 21% abnormal metaphases; the frequency decreased at higher fibre concentrations
  • Chrysotile-induced aberrations were mainly of the chromatid type, with no chromatid exchanges
  • Minutes and double minutes were found in BP-treated cells and only occasionally in chrysotile-treated cells
  • Chrysotile reduced the frequency of cells with 42 chromosomes even at 2 micrograms per ml, with a parallel increase in cells having 80-86 chromosomes
  • The authors considered the fall in abnormal cells at higher chrysotile doses probably related to toxicity and growth inhibition
• The authors' conclusion: The authors concluded that their results confirm chrysotile fibres are clastogenic for some cultured cells and show that the fibres induce chromosome damage in target rat pleural mesothelial cells
• Limitations the authors state:
  • About 40% of metaphases had a chromosome number other than 42; the authors thought the cells had likely undergone some spontaneous transformation
  • Whether cells remained diploid could not be determined without analysing banded metaphases
  • The reason aberrations decreased at higher chrysotile doses was not clear

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Mesothelial Cells.

Related studies

• In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene — M.J. Paterour, J. Bignon, et al. (1985)
• Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene — M.C. Jaurand, I. Bastie-Sigeac, et al. (1983)
• Sister chromatid exchanges in rat pleural mesothelial cells treated with crocidolite, attapulgite, or benzo 3-4 pyrene — S. Achard, M. Perderiset, et al. (1987)
• Morphological transformation of Syrian hamster embryo cells induced by mineral fibres and the alleged enhancement of benzo[a]pyrene — S.O. Mikalsen, E. Rivedal, et al. (1988)
• The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study — N.S. Wang, M.C. Jaurand, et al. (1987)
• Coinhibition of viral interferon induction by benzo[a]pyrene and chrysotile asbestos — N. Hahon, J.A. Booth (1986)

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