Production of reactive oxygen species by man-made vitreous fibres in human polymorphonuclear leukocytes

Our plain-English summary of Production of reactive oxygen species by man-made vitreous fibres in human polymorphonuclear leukocytes, by M. Ruotsalainen, M.R. Hirvonen, K. Luoto, et al (Human & Experimental Toxicology, 1999).

The study

• Authors: M. Ruotsalainen, M.R. Hirvonen, K. Luoto, K.M. Savolainen
• Journal: Human & Experimental Toxicology
• Published: 1999;18(6):354-62
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Human polymorphonuclear leukocytes (PMNL) or erythrocytes, isolated from human blood, were exposed to graded doses of asbestos (chrysotile), quartz, or man-made vitreous fibres (MMVF), i.e. refractory ceramic fibres (RCF), glasswool, or rockwool fibres. None of the MMVF affected either the viability of PMNL, as measured by trypan blue exclusion test, or induced haemolysis, whereas the positive controls, quartz and chrysotile, dose-dependently induced haemolysis in PMNL. MMVF did not increase the release of lactate dehydrogenase (LDH) from the PMNL, whereas the positive controls, chrysotile and quartz, induced a marked and dose-dependent release of LDH. When PMNL were exposed to MMVF, some of the fibre types slightly increased the levels of free intracellular calcium ([Ca2+]i) within the cells in a manner similar to that induced by chrysotile or quartz. All MMVF induced a dose-dependent production of reactive oxygen species (ROS) in PMNL, with RCF-induced production of ROS being the most marked. Production of ROS by MMVF seemed to depend on the availability of extracellular calcium because it could be attenuated with a Ca2+ channel blocker, verapamil, or a Ca2+ chelating agent, EGTA. Production of ROS may be a common pathway through which PMNL respond to MMVF-induced cell activation, but alterations of levels of free intracellular Ca2+ do not seem to be an absolute prerequisite for this effect. Fibre length seemed not to be an important factor in affecting the ability of MMVF to induce ROS production in PMNL. However, the balance between different elements in the fibre seemed importantly to affect the biological activity of a fibre.

In plain English

This laboratory study tested how white blood cells (polymorphonuclear leukocytes) and red blood cells from healthy donors reacted to man-made vitreous fibres. They were two refractory ceramic, two glasswool (one with and without binder) and three rockwool fibres. Chrysotile asbestos and quartz were comparison substances. None of the man-made fibres lowered cell survival, significantly raised release of LDH (an enzyme signalling cell damage) or broke open red cells. Chrysotile and quartz raised LDH release and broke open red cells; at the highest dose, chrysotile caused 99.4% and quartz 64.3% of maximal breakdown. Their effect on white-cell survival was not tested here. Some man-made fibres slightly raised calcium inside white cells; all increased production of reactive oxygen species, most strongly the refractory ceramic fibres. Among four fibres tested further, verapamil, a calcium channel blocker, at its highest dose reduced this for all four; EGTA, a calcium-binding agent, for three. The chrysotile and quartz calcium and reactive oxygen results came from earlier studies. The authors concluded that fibre length seemed unimportant within the sizes tested, but the balance of chemical elements might matter.

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 isolated human blood cells
• Who was studied: Polymorphonuclear leukocytes (and, for haemolysis tests, erythrocytes) isolated from the blood of healthy adult donors in Finland. The number of donors is not stated.
• Exposure: Man-made vitreous fibres supplied by Paroc Oy Ab: fibres 1 and 7 refractory ceramic fibres; fibres 2 and 3 glasswool (2a without binder, 2b with binder); fibres 4, 5 and 6 rockwool. UICC chrysotile A and Min-u-sil quartz were positive controls. Doses were printed as 10 to 1000 mg/ml depending on the test.
• Main results:
  • White-cell viability after 30 minutes at the highest man-made fibre dose (printed as 1000 mg/ml) was always more than 90%; control cells were 98.6% viable.
  • Man-made fibres did not significantly increase LDH release from white cells (0 to 11.0%).
  • At the highest dose, quartz induced 36.4% and chrysotile 56.1% LDH release relative to the positive control value.
  • In red blood cells, the highest dose of quartz caused haemolysis of 64.3% and chrysotile 99.4% of positive control values. Man-made fibres showed no haemolytic activity.
  • White-cell viability after exposure to quartz or chrysotile was not tested in this study.
  • At the highest dose (printed as 500 mg/ml), refractory ceramic fibres 1 and 7, glasswool fibre 3 and rockwool fibre 6 slightly increased free intracellular calcium in white cells.
  • Glasswool without a binder (fibre 2a) tended to raise intracellular calcium; glasswool with a binder (fibre 2b) did not.
  • All man-made fibres increased reactive oxygen species production. Unstimulated white cells measured 3.4 mV (plus or minus 0.2). At the highest dose, refractory ceramic fibre 1 produced 286.3 mV (plus or minus 46.1) and fibre 7 produced 226.4 mV (plus or minus 1.3).
  • The calcium tests on reactive oxygen production used four selected fibres: refractory ceramic fibres 1 and 7, glasswool fibre 3 and rockwool fibre 4.
  • The highest dose of the calcium channel blocker verapamil significantly reduced reactive oxygen production induced by all four of these fibres.
  • The calcium chelator EGTA significantly reduced reactive oxygen production induced by fibres 3, 4 and 7.
  • The chrysotile and quartz experiments on intracellular calcium and reactive oxygen species were carried out in earlier studies and are not reported in detail here.
• The authors' conclusion: The authors concluded that fibre length was not an important factor in the ability of man-made vitreous fibres to induce reactive oxygen production in these cells, at least within the size range used. They suggested that the balance between different elements in a fibre seems to contribute to its biological activity.
• Limitations the authors state:
  • The authors noted that size differences may need to be much larger than those in this study to be detected by chemiluminescence measurements.
  • The authors stated that their observations did not clearly identify any single chemical constituent responsible for reactive oxygen production.
  • Viability of the cells after exposure to quartz or chrysotile was not studied here; the authors relied on earlier data.

Topics

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

Medical terms in this study, explained in our Lexicon: Reactive Oxygen Species (ROS), Vitreous, Chrysotile, Lactate Dehydrogenase (LDH).

Related studies

• Changes in free intracellular calcium and production of reactive oxygen metabolites in human leukocytes by soluble and particulate stimuli — M. Tuomala, M.R. Hirvonen, et al. (1993)
• Production of reactive oxygen metabolites induced by asbestos fibres in human polymorphonuclear leucocytes — M. Hedenborg, M. Klockars (1987)
• Cellular mechanisms of reactive oxygen metabolite generation from human polymorphonuclear leukocytes induced by crocidolite asbestos — T. Ishizaki, E. Yano, et al. (1997)
• Crocidolite-induced reactive oxygen metabolites generation from human polymorphonuclear leukocytes — T. Ishizaki, E. Yano, et al. (1994)
• Chemiluminescent detection of induced reactive oxygen metabolite production of human polymorphonuclear leucocytes by anthophyllite asbestos — T. Iwata, N. Kohyama, et al. (2002)
• IgG and IgA enhance the chrysotile-induced production of reactive oxygen metabolites by human polymorphonuclear leucocytes — M. Klockars, M. Hedenborg, et al. (1989)

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