Cytotoxicity of heated chrysotile

Our plain-English summary of Cytotoxicity of heated chrysotile, by H. Hayashi (Environmental Health Perspectives, 1974).

The study

• Author: H. Hayashi
• Journal: Environmental Health Perspectives
• Published: 1974;9:267-70
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cytotoxicity and hemolysis were studied in chrysotile and quartz. The biological activity of the surface seemed to be different between chrysotile and quartz. Quartz lost its cytotoxicity on heating over about 500 degrees C. However chrysotile showed remarkable toxicity and induced hemolysis on heating between 650 and 800 degrees C, compared with the original unheated specimens. The mice injected intraperitoneally with minerals heated in this temperature range generally died within 48 hr after injection, while those injected with untreated chrysotile or chrysotile heated in the other heat ranges did not. The products in this range were highly disorded materials. It was assumed that the change of biological effects resulting from heat treatment may be related to the disordered state of chrysotile in the process of transformation into forsterite. The relationship between chemical character and cytotoxicity of the heated chrysotile specimens was also studied.

In plain English

This was a laboratory study that included an animal experiment. The author heated chrysotile asbestos (a UICC reference sample) for 1 hour at various temperatures. The author then tested its effects on macrophages (immune cells), on red blood cells (hemolysis, meaning the cells burst), and in mice injected in the abdominal cavity. Quartz dust was also tested. Hemolysis caused by chrysotile was striking after heating at 500 to 800 degrees C. Adding the protein albumin greatly reduced the effects of unheated chrysotile, but much less so for heated samples. Halving hemolysis took 11 micrograms of albumin for unheated chrysotile but 4000 micrograms for chrysotile heated at 750 degrees C. All mice injected with chrysotile heated at 650 or 750 degrees C died within 2 days. When heated to 500 to 700 degrees C, chrysotile was converting into forsterite, with both minerals present together. The author suggested that the changed biological effects may be related to the disordered state of the mineral during this transformation. The article does not report how many mice were used.

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 (cell) experiments with an animal experiment in mice
• Who was studied: Macrophages, red blood cells (erythrocytes) and mice exposed to chrysotile (UICC) samples. Quartz was also tested. The number of mice is not reported. The article does not state where the experiments were done; the author's listed affiliation is the National Institute of Industrial Health, Kawasaki, Japan.
• Exposure: Chrysotile (UICC) heated at various temperatures for 1 hour, compared with unheated chrysotile. Alkali-treated and ground quartz were also tested.
• Main results:
  • Hemolysis caused by chrysotile was striking after heating in the range 500 to 800 degrees C.
  • In the macrophage test, lactic acid production increased up to 500 degrees C. It then fell abruptly up to 650 degrees C, and rose again with higher heating temperature.
  • Albumin markedly reduced the inhibitory effect of unheated chrysotile on lactic acid production. It did not reduce the effect of chrysotile heated at 650 degrees C.
  • Halving hemolysis took 11 micrograms of albumin for unheated chrysotile, compared with 4000 micrograms for chrysotile heated at 750 degrees C.
  • All mice injected with chrysotile heated at 650 or 750 degrees C died within 2 days. Mice injected with untreated chrysotile, or with chrysotile heated at other temperatures, did not.
  • Samples heated at 650 and 750 degrees C were agitated in water. That water had a higher pH, and more dissolved silicon and magnesium, than water from the other samples.
  • X-ray and infrared analysis showed that chrysotile was converted into forsterite on heating to 500 to 700 degrees C. Chrysotile and forsterite coexisted in this range.
  • When pH was adjusted to 7.8, the samples' effects on macrophages were nearly the same. Hemolysis caused by chrysotile heated at 650 degrees C did not depend on pH.
  • Quartz lost its cytotoxicity when heated above about 500 degrees C. This is stated in the article's summary paragraph.
• The authors' conclusion: The author assumed that the change in biological effects caused by heating may be related to the disordered state of chrysotile as it transforms into forsterite.

Topics

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

Related studies

• Experimental studies on the effects of heated chrysotile asbestos and automobile brake lining dust injected into the body cavities of mice — J.M. Davis, S.W. Coniam (1973)
• Cytotoxicity of respirable dusts from industrial minerals: comparison of two naturally occurring and two man-made silicates — D. Nadeau, L. Fouquette-Couture, et al. (1987)
• Biological effects and comparative cytotoxicity of thermal transformed asbestos-containing materials in a human alveolar epithelial cell line — F. Giantomassi, A.F. Gualtieri, et al. (2010)
• Comparison of cytotoxicity of man-made vitreous fibres — K. Luoto, M. Holopainen, et al. (1997)
• Effectiveness of serum megakaryocyte potentiating factor in evaluating the effects of chrysotile and its heated products on respiratory organs — A. Takata, H. Yamauchi, et al. (2011)
• Thermal modification of chrysotile asbestos: evidence for decreased cytotoxicity — R. Valentine, M.J. Chang, et al. (1983)

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