Cytotoxicity and multinucleate giant cell formation in Chinese hamster lung fibroblast caused by crocidolite and chrysotile

Our plain-English summary of Cytotoxicity and multinucleate giant cell formation in Chinese hamster lung fibroblast caused by crocidolite and chrysotile, by Y.C. Hong, S.S. Choi (Journal of Korean Medical Science, 1997).

The study

• Authors: Y.C. Hong, S.S. Choi
• Journal: Journal of Korean Medical Science
• Published: 1997;12(2):99-104
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The mechanism of carcinogenic action of asbestos remains unclear but the physical properties of the fiber appear to be important in this process. Asbestos may cause multinucleate giant cell formation primarily by interfering with the normal course of mitosis. We evaluated the cytotoxicity and multinucleate giant cell formation induced by crocidolite and chrysotile in Chinese hamster lung fibroblast (V79 cell) with observation of phagocytic activities. Asbestos fibers were rapidly ingested by V79 cells and most fibers were inside the cells. Cytotoxicity was evaluated by observing inhibition of V79 cell proliferation with trypan blue exclusion test. For determination of frequency of multinucleate giant cells, the cells were treated with different doses of crocidolite or chrysotile for 72 hours. Crocidolite and chrysotile induced cytotoxicity in V79 cells in a dose-dependent manner. The pattern of inhibition of cell proliferation is similar for both types of fibers, but chrysotile was more potent at the highest level (20.0 micrograms/ml) of fiber concentration. There was a good relationship (regression coefficientcrocidolite = 0.02, P < 0.01; regression coefficientchrysotile = 0.04, P < 0.01) between the dose of both asbestos fibers and the frequency of multinucleate giant cells. Chrysotile was again more potent at inducing multinucleate giant cells in higher levels of fiber concentrations. We found that asbestos fibers were cytotoxic after phagocytosis and induced multinucleate giant cells by interfering mitosis.

In plain English

This was a laboratory experiment on cells grown in dishes. It used Chinese hamster lung fibroblasts, called V79 cells, and exposed them to UICC standard crocidolite or chrysotile asbestos at 0.16 to 20.0 micrograms per millilitre. Under scanning electron microscopy, the cells rapidly took in the fibers, and most fibers ended up inside the cells. Both fibers reduced cell growth after 24 hours, and the effect grew with the dose. Chrysotile left the fewest living cells at the highest dose. The trypan blue dye test suggested that most exposed cells were still alive. After 72 hours, both fibers increased the number of multinucleate giant cells, which are enlarged cells with many nuclei, as the dose rose. At 20 micrograms per millilitre the increase was over 100-fold, and chrysotile was more potent at that dose. The authors concluded that the cytotoxic effect was closely associated with the cells taking in the fibers. They also concluded that giant cell formation, as a sign of disturbed cell division, seems to be a useful marker for testing asbestos carcinogenicity. They noted that this change is not specific to asbestos.

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: Chinese hamster lung fibroblasts (V79 cells) obtained from the American Type Culture Collection, grown in duplicated culture flasks; no humans or animals were studied
• Exposure: UICC standard crocidolite (average diameter 0.35 µm) and chrysotile (average diameter 0.22 µm), at concentrations from 0.16 to 20.0 µg/ml; 24 hours of incubation for the cytotoxicity test and 72 hours for giant cell counts
• Main results:
  • In V79 cells exposed to either fiber, scanning electron microscopy showed most fibers inside the cells; long fibers often penetrated the cells
  • Both crocidolite and chrysotile inhibited V79 cell proliferation significantly and in a dose-dependent manner (regression coefficient for crocidolite -0.37, P<0.01; for chrysotile -0.60, P<0.01)
  • Doses that markedly inhibited growth had little effect on trypan blue exclusion, which the authors took to suggest that most asbestos-exposed cells were still alive
  • Chrysotile produced the lowest number of viable cells at the highest fiber concentration
  • The dose of both fibers was statistically significantly related to the frequency of multinucleate giant cells (regression coefficient for crocidolite 0.02, P<0.01; for chrysotile 0.04, P<0.01)
  • At the lowest dose (0.16 µg/ml), giant cells rose slightly above background in crocidolite-treated cells, with no change in chrysotile-treated cells
  • After 72 hours at 20 µg/ml, both fibers increased the frequency of multinucleate giant cells over 100-fold, and chrysotile was more potent at that dose
  • In giant cells from asbestos-treated cultures, the number of nuclei in a single cell sometimes rose to over 10
• The authors' conclusion: The authors concluded that the cytotoxic effect of both fibers was closely associated with phagocytic activity. They also concluded that multinucleate giant cell formation, as an index of mitotic disturbance, seems to be a useful marker in carcinogenesis assays of asbestos fibers.
• Limitations the authors state:
  • The authors stated that multinucleate giant cell formation is not a change specific to asbestos, and that other mineral fibers of similar dimensions may have the same effect
  • The authors noted that these giant cells are unlikely to give rise to tumor cells directly, because they cannot keep multiplying

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: Fibroblast, Crocidolite, Chrysotile, Carcinogenic, Phagocytosis.

Related studies

• Amosite, chrysotile and crocidolite asbestos are mutagenic in Chinese hamster lung cells — S.L. Huang (1979)
• A comparison of the cytogenetic response to asbestos and glass fibre in Chinese hamster and human cell lines. Demonstration of growth inhibition in primary human fibroblasts — A.M. Sincock, J.D. Delhanty, et al. (1982)
• Fibre-induced lipid peroxidation leads to DNA adduct formation in Salmonella typhimurium TA104 and rat lung fibroblasts — P.J. Howden, S.P. Faux (1996)
• Genotoxicity and cytotoxicity of multi-wall carbon nanotubes in cultured Chinese hamster lung cells in comparison with chrysotile A fibers — M. Asakura, T. Sasaki, et al. (2010)
• Effects of asbestos fibers on cell division, cell survival, and formation of thioguanine-resistant mutants in Chinese hamster ovary cells — K. Kenne, S. Ljungquist, et al. (1986)
• Kerosene soot genotoxicity: enhanced effect upon co-exposure with chrysotile asbestos in Syrian hamster embryo fibroblasts — M. Lohani, E. Dopp, et al. (2000)

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