Measurement of reactive oxygen metabolites produced by human monocyte-derived macrophages exposed to mineral dusts

Our plain-English summary of Measurement of reactive oxygen metabolites produced by human monocyte-derived macrophages exposed to mineral dusts, by P. Nyberg, M. Klockars (International Journal of Experimental Pathology, 1990).

The study

• Authors: P. Nyberg, M. Klockars
• Journal: International Journal of Experimental Pathology
• Published: 1990;71(4):537-44
• Cited by: 29 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

The aim of the present work was to develop an in-vitro model for studying mineral dust-induced production of reactive oxygen metabolites by human macrophages. Monocytes isolated from human buffy coats were cultured in vitro for 1-6 days. Quartz particles induced both luminol- and lucigenin-dependent chemiluminescence (CL) by the adherent cells. However, the luminol response decreased form day to day, obviously due to a decrease in the myeloperoxidase (MPO) activity of the cells, whereas the lucigenin response showed no such MPO dependence. The luminol response was inhibited by superoxide dismutase (SOD), catalase, and the MPO-inhibitor azide, while the lucigenin response was inhibited by SOD and catalase but stimulated by azide. There was a positive correlation between the lucigenin responses and the results obtained with the established cytochrome c assay for superoxide, when opsonized zymosan was used as a stimulant. The effects of quartz, titanium dioxide, chrysotile asbestos, and wollastonite particles were investigated with the lucigenin assay. Quartz and chrysotile caused prominent light emission by 6-day-old macrophages, whereas titanium dioxide and wollastonite caused weak responses. We conclude that mineral dusts induce production of reactive oxygen metabolites by human monocyte-derived macrophages, and that the quantitative responses depend on both physical and physicochemical dust properties, the nature of which are still to be defined.

In plain English

This was a laboratory study. The authors aimed to develop a test-tube model for measuring how human macrophages (scavenger immune cells) produce reactive oxygen compounds when exposed to mineral dusts. The cells were grown from blood supplied by healthy donors through the Finnish Red Cross. Using quartz particles, the authors compared two light-producing chemical probes, luminol and lucigenin. The luminol signal fell as the cells matured, and by day 6 the lucigenin signal was stronger. With lucigenin, they then tested quartz, titanium dioxide, chrysotile A asbestos and wollastonite on 6-day-old cells. Quartz and chrysotile caused prominent light emission. Titanium dioxide and wollastonite, which the authors used as inert control dusts, caused weak responses. More than 90% of the adherent cells remained alive after 20 minutes of exposure to 100 micrograms per ml of each particle. The authors concluded that mineral dusts induce production of reactive oxygen compounds by these cells, and that the size of the response depends on dust properties not yet defined. They cautioned that the role of hydrogen peroxide in the lucigenin test remains unclear.

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 study developing a cell-culture model and chemiluminescence assay
• Who was studied: Macrophages grown in culture for 1 to 6 days from monocytes isolated from buffy coats of healthy blood donors, obtained from the Finnish Red Cross Blood Transfusion Service; the number of donors is not stated
• Exposure: Quartz, titanium dioxide, chrysotile A asbestos (International Union Against Cancer standard sample) and wollastonite FW 325, mainly at 100 micrograms per ml; opsonized zymosan was used as a standard stimulant
• Main results:
  • In quartz-exposed cultures, the luminol response fell with culture age. By day 3 it had dropped to the lucigenin level, and on day 6 the lucigenin responses were stronger than the luminol responses.
  • In quartz-exposed cells on day 1, SOD and catalase reduced both luminol and lucigenin light emission, while azide increased lucigenin and reduced luminol light emission
  • Lucigenin responses could not be matched to the established cytochrome c superoxide test for quartz-stimulated cells, but correlated closely with it when cells were stimulated with opsonized zymosan
  • In 6-day-old macrophages, quartz and chrysotile caused prominent lucigenin light emission, while titanium dioxide and wollastonite caused weak responses (shown as representative curves; no numbers given)
  • Light emission from the inert control dusts (titanium dioxide and wollastonite) was described by the authors as significantly weaker
  • More than 90% of adherent cells were viable, by trypan blue dye exclusion, after 20 minutes of exposure to each particle type at 100 micrograms per ml
• The authors' conclusion: The authors concluded that mineral dusts induce production of reactive oxygen metabolites by human monocyte-derived macrophages, and that the quantitative responses depend on physical and physicochemical dust properties
• Limitations the authors state:
  • The lucigenin test can be used for superoxide only cautiously, because the role of hydrogen peroxide in it remains unclear
  • The dust properties that determine the size of the response have not yet been defined

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

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

Related studies

• Polyvinylpyridine-N-oxide and carboxymethyl cellulose inhibit mineral dust-induced production of reactive oxygen species by human macrophages — P. Nyberg (1991)
• Effect of size of man-made and natural mineral fibers on chemiluminescent response in human monocyte-derived macrophages — M. Ohyama, T. Otake, et al. (2001)
• 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)
• Production of reactive oxygen species by phagocytic cells after exposure to glass wool and stone wool fibres - effect of fibre preincubation in aqueous solution — T. Zoller, W.J. Zeller (2000)
• Increased mineral dust-induced production of reactive oxygen species by blood monocytes from patients with malignant diseases — P.W. Nyberg, S.A. Nordman, et al. (1994)
• Pulmonary macrophages are attracted to inhaled particles through complement activation — D.B. Warheit, L.H. Overby, et al. (1988)

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