In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene

Our plain-English summary of In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene, by M.C. Jaurand, L. Magne, J.L. Boulmier, et al (Toxicology, 1981).

The study

• Authors: M.C. Jaurand, L. Magne, J.L. Boulmier, J. Bignon
• Journal: Toxicology
• Published: 1981;21(4):323-42
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The effects of 3 UICC asbestos fibres (A chrysotile, crocidolite, amosite) were observed in vitro on red blood cells (RBC) and alveolar macrophages (AM). THe reactivity of the fibres after leaching with 0.1 N oxalic acid or adsorption of SO2 or benzo-3,4-pyrene (BP) was studied. The haemolytic activity of crocidolite and amosite was very low. A cytotoxic effect on AM occurred when the fibres were present in high concentration (100 microgram/ml), this was characterized by a release of both cytoplasmic (LDH) and lysosomal (beta-galactosidase) enzymes. The leached fibres were more haemolytic than the unleached ones, and more beta-galactosidase (beta-Gal) than lactic dehydrogenase (LDH) was released from the AM. In contrast to the amphiboles, chrysotile fibres were highly haemolytic and induced a selective release of beta-Gal from AM. Leached fibres were less haemolytic and were cytotoxic for AM (both enzymes were released). Their in vitro reactivity was similar to that observed with quartz. The results showed that SO2 changed the reactivity very little. BP sorption on acid-leached chrysotile decreased the LDH release from AM. The difference in the in vitro reactivity related to the chemical state of asbestos fibres might explain the difference in their in vivo reactivity (latency, degree of fibrosis). This point is discussed.

In plain English

This was a laboratory (in vitro) study. The authors exposed human red blood cells and rabbit alveolar macrophages (lung scavenger cells) to UICC A chrysotile, crocidolite and amosite. Fibres were tested untreated, after leaching with 0.1 N oxalic acid, and after taking up sulfur dioxide (SO2) or benzo-3,4-pyrene (BP). BP-treated fibres were tested on macrophages only. Quartz, glass fibres and nemalite served as comparisons. At lower doses, untreated crocidolite and amosite had very weak effects on both cell types. At higher doses, the authors suggested these fibres were cytotoxic to macrophages. Chrysotile was highly haemolytic (it broke open red blood cells) and made macrophages release mainly a lysosomal enzyme. Acid leaching made the amphiboles more reactive. Leaching made chrysotile less haemolytic and its effect on macrophages similar to that of quartz. SO2 changed reactivity very little. BP on leached chrysotile cut LDH release from 20% to 5%. The authors suggested that leached amphiboles acting like chrysotile might help explain why tumours generally appear later after injection of amphibole fibres than after chrysotile. They did not check whether dispersing the fibres removed the SO2 or BP.

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 cells
• Who was studied: Human red blood cells from healthy donors and alveolar macrophages taken from rabbits. The article does not state how many donors or animals were used.
• Exposure: UICC A chrysotile, crocidolite and amosite, tested untreated, leached with 0.1 N oxalic acid, or with adsorbed SO2 or benzo-3,4-pyrene. Comparison particles were two quartz samples, JM 104 glass fibres and nemalite. Macrophages were usually exposed to 50 micrograms per ml, with some tests at higher concentrations.
• Main results:
  • Untreated amosite and crocidolite had a similar, very weak effect on red blood cells and macrophages.
  • At 50 micrograms per ml, amosite had no effect on macrophages, and crocidolite led to release of 8% LDH.
  • With untreated amphiboles, macrophages released more enzyme as the fibre concentration increased.
  • The authors suggested that amphiboles were cytotoxic and killed the macrophages under these experimental conditions.
  • Untreated chrysotile at 50 micrograms per ml for 20 h led macrophages to release 20.1% beta-galactosidase but only 2.4% LDH.
  • The authors concluded that chrysotile fibres stimulate macrophages to release lysosomal enzymes.
  • At a mean concentration of 0.5 mg/ml, the amphibole fibres were about 100 times less haemolytic than chrysotile.
  • After oxalic acid leaching, amosite and crocidolite had greater effects than untreated fibres on both red blood cells and macrophages.
  • Less than 2 mg of leached amphibole fibres was needed for 100% haemolysis, compared with 4 mg of untreated fibres.
  • Oxalic acid leaching cut chrysotile's initial rate of haemolysis at 0.5 mg/ml by 5 times, to 25% per minute.
  • On macrophages, leached chrysotile acted like quartz: it was cytotoxic and released both enzymes, mostly LDH.
  • Adsorbed SO2 changed fibre reactivity very little.
  • BP-treated fibres were tested only on macrophages, not on red blood cells.
  • BP adsorbed onto leached chrysotile reduced LDH release from macrophages from 20% to 5%.
  • Across the particles tested, LDH release rose in a linear relationship with each particle's capacity to adsorb the phospholipid DPPC (r = 0.90).
• The authors' conclusion: The authors noted that, after leaching, amphibole activity was similar to that of chrysotile. They suggested this could explain why the latent period for tumour production is generally longer after injection of amphibole fibres than after chrysotile. Tumours were not studied in this experiment.
• Limitations the authors state:
  • The authors did not check whether the sonication used to disperse the fibres removed the SO2 or BP.
  • The authors described their results with leached fibres as less clear-cut.
  • Leached chrysotile fibres were sometimes massed together, so accurate size measurements were not possible.
  • Results for one crocidolite concentration (100 micrograms per ml) were uncertain.
  • The nemalite comparison samples contained traces of talc, which may have affected the cells.

Topics

Medical terms in this study, explained in our Lexicon: Alveolar Macrophage, UICC, Chrysotile, Crocidolite, Amosite, Amphibole Group, LDH Release, Latency.

Related studies

• Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells — M.C. Jaurand, J. Bignon, et al. (1978)
• 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)
• Leaching of chrysotile asbestos in human lungs. Correlation with in vitro studies using rabbit alveolar macrophages — M.C. Jaurand, J. Bignon, et al. (1977)
• Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene — M.C. Jaurand, I. Bastie-Sigeac, et al. (1983)
• In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene — M.J. Paterour, J. Bignon, et al. (1985)
• Response of bovine alveolar macrophages in vitro to welding fume particles — L.R. White, A.B. Marthinsen, et al. (1983)

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