A spin label study of the effects of asbestos, quartz, and titanium dioxide dusts on the bovine erythrocyte membrane

Our plain-English summary of A spin label study of the effects of asbestos, quartz, and titanium dioxide dusts on the bovine erythrocyte membrane, by W. Leyko, E. Gendek (British Journal of Industrial Medicine, 1985).

The study

• Authors: W. Leyko, E. Gendek
• Journal: British Journal of Industrial Medicine
• Published: 1985;42(4):281-4
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The effects of five UICC asbestos samples, titanium dioxide, and quartz on the bovine red cell membrane have been studied in erythrocyte ghosts by the spin labelling technique. Analysis of the electron paramagnetic resonance (EPR) spectra of two sulphydryl reactive spin labels and one fatty acid spin label in red cell ghosts showed modifications in membrane protein after asbestos treatment but no alterations in membrane lipids. In experiments with quartz no membrane changes were noted but titanium dioxide altered the proteins bound with the protein reactive spin label used in the present study. The possible mechanism for these effects is discussed.

In plain English

This was a laboratory study of cow red blood cell membranes, not of people or of disease. The authors exposed membranes ("ghosts") prepared from bovine blood to five UICC asbestos samples (chrysotile A, chrysotile B, crocidolite, amosite and anthophyllite), to quartz DQ-120 and to titanium dioxide. They then used chemical tags called spin labels to detect changes in membrane proteins and lipids. With one protein label, chrysotiles raised a measured ratio, while crocidolite, amosite, anthophyllite and titanium dioxide lowered it. With a second protein label, asbestos-treated membranes showed an increase in rotational correlation time, which the authors read as stronger immobilisation of membrane proteins; titanium dioxide and quartz did not change it. A lipid label showed no change after any dust, and quartz produced no membrane changes. The authors interpreted the results as suggesting that chrysotile releases a membrane protein called spectrin and that all the asbestos types increased the immobilisation of membrane proteins. They noted that their buffer may have blocked asbestos-lipid interactions, and that lipid changes could occur deeper in the membrane than they measured.

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) experiment using spin labelling and electron paramagnetic resonance (EPR) spectroscopy on red cell membranes
• Who was studied: Erythrocyte membranes (red cell ghosts) prepared from bovine blood collected at an abattoir. No humans or living animals were studied.
• Exposure: UICC asbestos samples chrysotile A, chrysotile B, crocidolite, amosite and anthophyllite, plus quartz DQ-120 and titanium dioxide
• Main results:
  • With the maleimide protein spin label (MSL), the ratio of weakly to strongly immobilised label increased in membranes treated with chrysotiles. It decreased with crocidolite, amosite, anthophyllite and titanium dioxide.
  • With the iodoacetamide protein spin label (ISL), the rotational correlation time increased in asbestos-treated membranes. The authors read this as increased immobilisation, meaning reduced mobility, of membrane proteins. Titanium dioxide and quartz DQ-120 did not alter this parameter.
  • With the lipid spin label, the order parameter S of control membranes was 0.61 plus or minus 0.01. It was not altered after treatment with any of the dusts.
  • Quartz produced no membrane changes. Titanium dioxide altered proteins bound with one of the protein-reactive labels.
• The authors' conclusion: The authors concluded that their results suggest spectrin is released from the membrane after chrysotile treatment. They also concluded that all asbestos types appeared to increase membrane protein immobilisation, and that phospholipid order was not altered by the dusts studied.
• Limitations the authors state:
  • The rotational correlation time was not calculated for the MSL spectrum.
  • The location of the MSL label in the membrane may differ from that assumed from earlier work, because of methodological differences.
  • Lipid changes might occur deeper in the membrane than was studied.
  • The phosphate buffer used may have prevented asbestos-phospholipid interactions.

Topics

Medical terms in this study, explained in our Lexicon: UICC.

Related studies

• A spin label study of the effect of chrysotile asbestos on erythrocyte membranes — E. Gendek, G. Bartosz, et al. (1984)
• Kinetics of the bronchoalveolar leucocyte response in rats during exposure to equal airborne mass concentrations of quartz, chrysotile asbestos, or titanium dioxide — K. Donaldson, R.E. Bolton, et al. (1988)
• Experimental studies in rats on the effects of asbestos inhalation coupled with the inhalation of titanium dioxide or quartz — J.M. Davis, A.D. Jones, et al. (1991)
• DNA double-strand breaks by asbestos, silica, and titanium dioxide: possible biomarker of carcinogenic potential? — Z. Msiska, M. Pacurari, et al. (2010)
• Acute biological effects of intratracheally instilled titanium dioxide whiskers compared with nonfibrous titanium dioxide and amosite in rats — Y. Ishihara, H. Kyono, et al. (1999)
• On the defensive action of glutamate against the cytotoxicity and fibrogenicity of quartz dust — K.I. Morosova, G.V. Aronova, et al. (1982)

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