ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro

Our plain-English summary of ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro, by E. Dopp, S. Yadav, F.A. Ansari, et al (Particle and Fibre Toxicology, 2005).

The study

• Authors: E. Dopp, S. Yadav, F.A. Ansari, K. Bhattacharya, U. von Recklinghausen, U. Rauen, K. Rödelsperger, B. Shokouhi, S. Geh, Q. Rahman
• Journal: Particle and Fibre Toxicology
• Published: 2005;2:9
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time-dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO4 appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both.

In plain English

This laboratory study tested asbestos-cement powder, made by grinding asbestos cement sheet, on V79 cells (Chinese hamster lung fibroblast cells) grown in culture. It was compared with UICC chrysotile asbestos, with calcium sulphate (CaSO4) as the negative control. Cell viability fell for both asbestos-cement powder and chrysotile as concentration and exposure time increased, and chrysotile was more cytotoxic. Asbestos-cement powder caused a significant increase in micronuclei, a sign of chromosome damage, at all tested concentrations after 24 and 48 hours. Chrysotile at 1 µg/cm2 caused about as many micronuclei as asbestos-cement powder at 3 µg/cm2. Combining the two raised micronuclei, but the difference from either material alone was not statistically significant. Iron-binding chemicals reduced micronuclei to control levels or lower. Both materials increased TBARS, a marker of oxidative damage. The authors concluded that both materials had cytotoxic and genotoxic properties, that chrysotile was more toxic, and that combined exposure showed weak additive genotoxic effects.

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: V79 cells (Chinese hamster lung fibroblast cells) obtained from the European Collection of Cell Cultures; no people or animals were studied
• Exposure: Asbestos-cement powder ground from asbestos cement sheet, compared with UICC chrysotile (positive control) and CaSO4 (negative control), mostly at 1 to 20 µg/cm2 for 24, 48 and 72 hours
• Main results:
  • Cell viability decreased with increasing concentration and exposure time for both asbestos-cement powder and chrysotile
  • Chrysotile was more cytotoxic than asbestos-cement powder at all three exposure times
  • Asbestos-cement powder caused a significant increase in micronucleated cells at all concentrations tested (1, 3, 5 and 10 µg/cm2) after 24 and 48 hours
  • Chrysotile at 1 µg/cm2 induced almost the same number of micronuclei as asbestos-cement powder at 3 µg/cm2
  • Co-exposure to asbestos-cement powder (3 µg/cm2) and chrysotile (1 µg/cm2) increased micronuclei compared with either alone, but the difference was not statistically significant
  • In the kinetochore analysis, differences in kinetochore-negative micronuclei between exposed cells and the untreated control were not statistically significant
  • The iron chelators 2,2'-dipyridyl and desferal reduced the number of induced micronuclei to the control level or lower
  • TBARS (a marker of lipid peroxidation) reached 0.063 nmol/mg at 36 hours in asbestos-cement-exposed cells and 0.089 nmol/mg at 48 hours in chrysotile-exposed cells
  • In co-exposed cells, TBARS formation was delayed, reaching 0.089 nmol/mg at 72 hours
• The authors' conclusion: The authors concluded that both asbestos-cement powder and chrysotile were cytotoxic and genotoxic, that chrysotile was more toxic, and that co-exposure showed weak additive genotoxic effects

Topics

Medical terms in this study, explained in our Lexicon: Genotoxicity, Asbestos-Cement, Chrysotile, Reactive Oxygen Species (ROS), Micronuclei.

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