Effects of chrysotile and acid-treated chrysotile on macrophage cultures

Our plain-English summary of Effects of chrysotile and acid-treated chrysotile on macrophage cultures, by E.G. Beck, P.F. Holt, E.T. Nasrallah (British Journal of Industrial Medicine, 1971).

The study

• Authors: E.G. Beck, P.F. Holt, E.T. Nasrallah
• Journal: British Journal of Industrial Medicine
• Published: 1971;28(2):179-85
• Cited by: 46 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Beck, E. G., Holt, P. F., and Nasrallah, E. T. (1971).Brit. J. industr. Med.,28, 179-185. Effects of chrysotile and acid-treated chrysotile on macrophage cultures. The addition of chrysotile asbestos to monolayer cultures of peritoneal and alveolar macrophages produces an increase in membrane permeability, as measured by eosin uptake and lactic dehydrogenase activity of the supernatant fluid. The lactate synthesis is increased, however. It is suggested that the permeability of the cell membrane is increased while dust particles are being phagocytosed, which may take several hours when the particles are fibrous, but that this does not imply cell damage. Treatment of chrysotile with acid, which leaves a silica surface, results in a product that reduces lactate synthesis, implying cytotoxicity. This change is counteracted by poly(2-vinyl-pyridine 1-oxide). The polymer does not affect the properties of the native chrysotile.

In plain English

This laboratory experiment tested a high-grade Rhodesian chrysotile asbestos on cultured macrophages (scavenger cells) taken from the abdominal cavity (peritoneal) and the lungs (alveolar) of guinea-pigs. Cells were exposed to chrysotile, acid-treated chrysotile, each of these coated with a polymer (PVNO), quartz, corundum (a control dust) or no dust. Cell harm was judged at 3, 6 and 20 hours by eosin dye uptake, leakage of the enzyme LDH, and lactate production. In alveolar macrophages after 20 hours, 51% of cells took up dye with chrysotile, against 14% with no dust and 99% with quartz. Chrysotile raised dye uptake and LDH in both cell types, but it increased lactate production, whereas quartz decreased it. Acid-treated chrysotile raised dye uptake and LDH further and reduced lactate production. PVNO did not greatly change chrysotile's effects. Acid-treated chrysotile coated with PVNO gave results similar to untreated chrysotile. The authors concluded that chrysotile was not acutely toxic to cells under these conditions. They suggested the leakiness arose while fibres were slowly engulfed, and judged acid-treated chrysotile apparently more toxic.

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, with a separate chemical measurement of how much PVNO polymer sticks to chrysotile
• Who was studied: Cultured peritoneal and alveolar macrophages from guinea-pigs, 4 to 5 million cells per culture tube. Each table value is the average of four experiments. The article does not say where or when the experiments were done, beyond the authors' institutes in Düsseldorf and Reading. It was received for publication in June 1970.
• Exposure: A high-grade Rhodesian chrysotile, either untreated or treated with hydrochloric acid (which leaves a mainly silica surface), each with or without a PVNO polymer coating. It was added at 150 micrograms of dust per million cells. Quartz (DQ 12), corundum and no dust were used for comparison.
• Main results:
  • Alveolar macrophages, 20 hours: cells stained by eosin-Y were 14% (range 10-15) with no dust, 51% (40-61) with chrysotile, 76% (62-87) with acid-treated chrysotile and 99% (98-100) with quartz.
  • In alveolar macrophages, chrysotile increased eosin-Y uptake and LDH release, as quartz did. But chrysotile increased lactate production, while quartz decreased it. At 20 hours lactate was 220 micrograms with chrysotile, 152 with no dust and 30 with quartz.
  • Peritoneal macrophages, 20 hours: chrysotile increased eosin-Y staining (32% vs 14% with no dust) and LDH (157 vs 90 mU). Lactate also rose (402 vs 175 micrograms).
  • In peritoneal macrophages, acid-treated chrysotile increased eosin-Y uptake two to three times, considerably increased LDH and reduced lactate synthesis. At 20 hours, compared with untreated chrysotile, eosin staining was 70% vs 32%, LDH 525 vs 157 mU, and lactate 208 vs 402 micrograms.
  • The authors judged acid-treated chrysotile apparently more toxic to cells than untreated chrysotile.
  • Coating untreated chrysotile with PVNO did not greatly change its effects on alveolar macrophage cultures, although phagocytosis (engulfing of particles) was increased.
  • Acid-treated chrysotile coated with PVNO gave results similar to untreated chrysotile.
  • PVNO adsorption apparently reached a single complete layer at about 40 mg per g on acid-washed chrysotile, and at about 23 mg per g on chrysotile not treated with acid.
  • The authors suggested that the increased cell permeability seen with chrysotile probably occurs while the fibres are being engulfed, which can take many hours.
• The authors' conclusion: The authors concluded that, under the conditions of their experiments, chrysotile was not acutely cytotoxic (not acutely toxic to the cells).
• Limitations the authors state:
  • The authors note that repeated biological tests do not give identical values; each table value is an average of four experiments.
  • The authors state that the results with peritoneal macrophages were similar to those with alveolar macrophages but less significant.

Topics

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

Related studies

• Comparison of effects on macrophage cultures of glass fibre, glass powder, and chrysotile asbestos — E.G. Beck, P.F. Holt, et al. (1972)
• Response of cell cultures to asbestos fibers — J. Bruch (1974)
• Macrophage functions after exposure to mineral fibers — F. Tilkes, E.G. Beck (1983)
• The effects of chrysotile asbestos dust on lung macrophages maintained in organ culture. An electron-microscope study — J.M. Davis (1967)
• In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene — M.C. Jaurand, L. Magne, et al. (1981)
• In vitro biodegradation of chrysotile fibres by alveolar macrophages and mesothelial cells in culture: comparison with a pH effect — M.C. Jaurand, A. Gaudichet, et al. (1984)

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