Metaphase and anaphase analysis of V79 cells exposed to erionite, UICC chrysotile and UICC crocidolite

Our plain-English summary of Metaphase and anaphase analysis of V79 cells exposed to erionite, UICC chrysotile and UICC crocidolite, by L.D. Palekar, J.F. Eyre, B.M. Most, et al (Carcinogenesis, 1987).

The study

• Authors: L.D. Palekar, J.F. Eyre, B.M. Most, D.L. Coffin
• Journal: Carcinogenesis
• Published: 1987;8(4):553-60
• Cited by: 43 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The cytogenetic effects of erionite treatment of V79 cells were compared with those of UICC crocidolite and UICC chrysotile treatment. A significant reduction in diploid cells with an accompanying increase in aneuploid and polyploid cells was observed with all three treatments. In the erionite-treated cultures, an increase in aneuploidy was observed at all dose levels ranging from 10 to 100 micrograms/ml, whereas in the crocidolite- and chrysotile-treated cultures, significant increases in aneuploidy were observed at all dose levels except the low dose, 10 micrograms/ml. Chromatid aberrations were observed in cultures treated with crocidolite and chrysotile and were especially pronounced at dose 100 micrograms/ml of chrysotile. The clastogenic effect of erionite was weaker but statistically significant at dose 100 micrograms/ml. An extrapolation of these cytogenetic changes over dose in number of fibers suggests that erionite was more reactive than the other two minerals in producing aneuploidy. The number of fibers required to produce a similar degree of cytogenetic effects was several orders of magnitude higher for chrysotile and crocidolite than erionite. These results correlate with the higher tumorigenic potency of erionite. In general, fewer cells treated with erionite entered anaphase than those treated with the other two minerals. As a result, abnormal anaphases representing chromosomal mis-segregation were observed only in the chrysotile- and crocidolite-treated cultures. To our knowledge, this is the first report on cytogenetic effects of erionite.

In plain English

This was a laboratory experiment on Chinese hamster lung cells (V79 cells), not a study of people. The authors exposed the cells for 24 hours to erionite, a fibrous non-asbestos mineral, or to UICC chrysotile or UICC crocidolite, at 10, 40, 60 and 100 micrograms per milliliter. They then examined the chromosomes in dividing cells. In untreated cultures, 89.7% of cells had the normal chromosome number. All three minerals significantly reduced that share. For erionite this held at every dose, and for chrysotile and crocidolite at 40 to 100 micrograms per milliliter. Chrysotile caused the most chromosome damage only at the highest dose; erionite's effect on such damage was significant only at that dose. Erionite most reduced the number of cells reaching the later stage of division (anaphase). Significant increases in abnormal anaphases were seen only with chrysotile. The erionite sample contained the fewest fibers per unit weight. The authors concluded that crocidolite and chrysotile needed 10 to 100 times more fibers than erionite to produce similar abnormal chromosome numbers, which may explain erionite's higher tumor-causing potency. This experiment did not test tumors. The authors called their significant findings exploratory.

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 examining chromosomes in dividing cells after 24-hour exposure to mineral fibers
• Who was studied: Chinese hamster lung V79 cells in culture; 600 control cells and 100 treated cells per dose level were scored for chromosome number
• Exposure: Erionite, UICC chrysotile and UICC crocidolite, each at 10, 40, 60 and 100 micrograms per milliliter for 24 hours; doses were also converted to numbers of fibers per milliliter
• Main results:
  • In untreated control cultures, 89.7% of cells were diploid (normal chromosome number), 10% were aneuploid and 0.3% were polyploid
  • All three minerals caused a significant decrease in diploid cells, with a parallel increase in aneuploid and polyploid cells
  • The reduction in diploid cells was significant for chrysotile and crocidolite at 40 to 100 micrograms per milliliter, and for erionite at all dose levels
  • The number of fibers per unit weight was highest in UICC chrysotile, intermediate in UICC crocidolite and lowest in erionite
  • If the trends in the dose-by-fiber-number figures can be extrapolated, fewer erionite fibers than crocidolite fibers, and considerably fewer than chrysotile fibers, were needed to produce similar percentages of non-diploid cells
  • The percentage of cells with chromosome aberrations was significantly increased with crocidolite at 40 and 60 micrograms per milliliter (6% each), chrysotile at 10, 60 and 100 micrograms per milliliter (4%, 5% and 15%), and erionite only at 100 micrograms per milliliter (5%). The control value was 0.83%.
  • Chrysotile produced the greatest percentage of cells with chromosome and chromatid aberrations, but only at the higher dose of 100 micrograms per milliliter
  • The chromosome-damaging (clastogenic) responses to crocidolite and erionite were weaker than the response to chrysotile
  • Erionite-treated cultures at 60 and 100 micrograms per milliliter had only 0.1% of cells in anaphase at both doses. The control value was 4.2%.
  • At the same two doses (60 and 100 micrograms per milliliter), 0.4% and 0.2% of chrysotile-treated cells were in anaphase, and 0.8% and 0.4% of crocidolite-treated cells
  • Abnormal anaphases were more frequent with chrysotile and crocidolite than with erionite
  • The only statistically significant anaphase results were in chrysotile-treated cultures at 10, 40 and 60 micrograms per milliliter, with total mis-segregations of 16.0%, 23.9% and 18.8% (100, 92 and 16 anaphases scored). The control value was 2.3%.
• The authors' conclusion: The authors concluded that, although the three minerals produced similar aneuploidy by mass dose, crocidolite and chrysotile needed 10 to 100 times more fibers than erionite to produce a similar effect. They suggested this may explain why erionite is more tumorigenic in humans and in animals.
• Limitations the authors state:
  • The analyses of the different kinds of effects were not independent, so the 'significant' findings are exploratory
  • Only limited quantitative anaphase analysis was possible because few cells were in anaphase at high mineral concentrations
  • Anaphase analysis detects only a small proportion of structural chromosome changes
  • It is unclear whether the chromosome changes come from fibers physically interfering with cell division or from other mechanisms

Topics

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

Medical terms in this study, explained in our Lexicon: erionite, UICC, Chrysotile, Crocidolite.

Related studies

• Induction of metaphase and anaphase/telophase abnormalities by asbestos fibers in rat pleural mesothelial cells in vitro — M. Yegles, L. Saint-Etienne, et al. (1993)
• Induction by asbestos fibers of anaphase abnormalities: mechanism for aneuploidy induction and possibly carcinogenesis — T.W. Hesterberg, J.C. Barrett (1985)
• 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)
• The in vitro genetic effects of fibrous erionite and crocidolite asbestos — K.T. Kelsey, E. Yano, et al. (1986)
• Significance of mass and number of fibers in the correlation of V79 cytotoxicity with tumorigenic potential of mineral fibers — L.D. Palekar, B.M. Most, et al. (1988)
• Role of fibre characteristics on cytotoxicity and induction of anaphase/telophase aberrations in rat pleural mesothelial cells in vitro: correlations with in vivo animal findings — M. Yegles, X. Janson, et al. (1995)

Browse more research in Carcinogenesis, or return to medical research.