Sister chromatid exchanges in rat pleural mesothelial cells treated with crocidolite, attapulgite, or benzo 3-4 pyrene

Our plain-English summary of Sister chromatid exchanges in rat pleural mesothelial cells treated with crocidolite, attapulgite, or benzo 3-4 pyrene, by S. Achard, M. Perderiset, M.C. Jaurand (British Journal of Industrial Medicine, 1987).

The study

• Authors: S. Achard, M. Perderiset, M.C. Jaurand
• Journal: British Journal of Industrial Medicine
• Published: 1987;44(4):281-3
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Summary of the article

The authors tested whether attapulgite fibres induced sister chromatid exchanges (SCEs) in cultured rat pleural mesothelial cells. They described these cells as target cells in fibre-related diseases. They compared the effects with crocidolite asbestos fibres and with benzo 3-4 pyrene (BP), a known mutagen. The attapulgite sample came from Senegal and had fibres shorter than 2 µm. The crocidolite was a Union Internationale contre le Cancer sample. Cells between the 12th and 15th passage were treated with 10, 15 or 20 µg/ml of fibres for 48 hours, or with 0.5 µg/ml BP dissolved in dimethyl sulphoxide (DMSO) or acetone for different periods. Cells were then incubated with 5-bromodeoxyuridine for 70 hours. Thirty metaphases were scored per condition, and groups were compared with the Mann-Whitney test. Attapulgite did not significantly increase SCEs at 10 or 20 µg/ml, although electron microscopy showed fibres inside the cells. Crocidolite significantly increased SCEs at all doses, by about 30% at 10 µg/ml and 40% at 15 µg/ml. The effect was lower at 20 µg/ml, which the authors suggested could be related to cytotoxicity. BP increased SCEs in both solvents, by 300% after 30 hours. The effect was stronger in acetone, and acetone alone produced a significant rise at 48 hours. The authors concluded that this short-fibre attapulgite did not induce SCEs, whereas crocidolite did. They considered both findings consistent with animal carcinogenicity data.

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In plain English

This was a laboratory experiment on cultured rat pleural mesothelial cells, by authors in Créteil, France. The authors tested whether attapulgite fibres, crocidolite asbestos fibres, and the chemical benzo 3-4 pyrene (BP) increased sister chromatid exchanges. These are a chromosome change used as a sensitive test for agents that damage genetic material. The attapulgite came from Senegal and its fibres were shorter than 2 micrometres. Cells were exposed to the fibres for 48 hours, and 30 dividing cells were scored for each treatment. Attapulgite at 10 and 20 micrograms per millilitre produced no significant increase. Crocidolite significantly increased exchanges at every dose tested: by about 30% at 10 and 40% at 15 micrograms per millilitre. The authors suggested the smaller effect at 20 might reflect cell toxicity. BP had a stronger effect: exchanges rose by 300% after 30 hours, while the rise with crocidolite did not exceed 48%. The authors concluded that, if the test is taken as an indicator of cancer-causing potency, their results did not disagree with animal studies, because this attapulgite sample contained short fibres.

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: In vitro laboratory experiment on cultured cells
• Who was studied: Cultured rat pleural mesothelial cells (secondary cultures, between the 12th and 15th passage), from a laboratory at CHU Henri Mondor, Créteil, France; 30 metaphases (dividing cells) scored per treatment, in two separate experiments
• Exposure: Attapulgite from Senegal (fibres less than 2 micrometres long; tested at 10 and 20 micrograms per millilitre) and UICC crocidolite (10, 15 and 20 micrograms per millilitre), each for 48 hours; also benzo 3-4 pyrene at 0.5 micrograms per millilitre dissolved in DMSO or acetone, for different periods
• Main results:
  • Attapulgite did not induce sister chromatid exchanges: there was no significant increase per metaphase at 10 or 20 micrograms per millilitre
  • The authors reported that attapulgite fibres had been taken up by the cells: intracellular fibres were seen with electron microscopy
  • Crocidolite significantly increased the number of sister chromatid exchanges per metaphase at all doses tested
  • Crocidolite at 10 micrograms per millilitre increased sister chromatid exchanges by about 30%, and at 15 micrograms per millilitre by 40%. The authors suggested the lower effect at 20 micrograms per millilitre could be related to cytotoxicity
  • Benzo 3-4 pyrene was more potent than crocidolite: after 30 hours, exchanges were enhanced by 300%, while the increase with crocidolite did not exceed 48%
  • The solvent acetone (0.1%) on its own also increased exchanges, significantly at 48 hours. Benzo 3-4 pyrene dissolved in acetone had a larger effect than when dissolved in DMSO
• The authors' conclusion: The authors concluded that this attapulgite sample did not induce sister chromatid exchanges in cultured rat pleural mesothelial cells, but crocidolite did. If the test is taken as an indicator of cancer-causing potency, they wrote, these results did not disagree with animal data. This attapulgite contained short fibres, which according to Stanton's hypothesis would not be carcinogenic. They also said the crocidolite result agreed with its known carcinogenicity in animals
• Limitations the authors state:
  • The test scores only cells in metaphase, so cells with high levels of exchanges may have been killed or badly injured and therefore not detected. The authors offered this as a possible reason for the lower effect at the highest crocidolite dose

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Crocidolite, Palygorskite (Attapulgite).

Related studies

• A retrospective cohort mortality study of males mining and milling attapulgite clay — R.J. Waxweiler, R.D. Zumwalde, et al. (1988)
• The lung biological activity of American attapulgite — R. Bégin, S. Massé, et al. (1987)
• Characterisation of palygorskite specimens from different geological locales for health hazard evaluation — R.P. Nolan, A.M. Langer, et al. (1991)
• Sister-chromatid exchange and cell kinetics in CHO-K1 cells, human fibroblasts and lymphoblastoid cells exposed in vitro to asbestos and glass fibre — G. Casey (1983)
• Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells — M.C. Jaurand, L. Kheuang, et al. (1986)
• In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene — M.J. Paterour, J. Bignon, et al. (1985)

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