Animal Experiments with Man-Made Mineral Fibres

Our plain-English summary of Animal Experiments with Man-Made Mineral Fibres, by J.C. Wagner, G. Berry, R.J. Hill, et al (1980).

The study

• Authors: J.C. Wagner, G. Berry, R.J. Hill, D.E. Munday, J.W. Skidmore
• Published: BIOLOGICAL EFFECTS OF MINERAL FIBRES (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 30., PP 361-362 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This short report described two rat experiments with man-made mineral fibres. The fibres were glass microfibre (Johns Manville code 100), glass wool, rock wool and slag wool. The wools were tested as supplied and after their resins were removed. In the first experiment, groups of 48 Sprague-Dawley rats were injected into the chest cavity (intrapleurally) with each dust. Another 48 received UICC African chrysotile asbestos, and 24 controls received saline. Mesotheliomas developed in six rats given chrysotile, four given glass microfibre, five given rock wool (three with resin, two without) and one given glass wool. In the second experiment, groups of 56 Fischer rats inhaled UICC Canadian chrysotile, glass microfibre, glass wool with or without resin, or rock wool for 35 hours a week for one year. Rats killed at three and 12 months showed reaction to dust in every exposed group, but less in the man-made fibre groups than in the chrysotile group. The chrysotile reaction was greater at 12 months than at three, while the man-made fibre groups changed little. The remaining rats were still alive, so final results were not yet available.

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: animal experiments: an intrapleural injection experiment and an inhalation experiment in rats (short report of work still in progress)
• Who was studied: Rats at the MRC Pneumoconiosis Unit, Penarth, UK. Injection experiment: 48 Sprague-Dawley rats per dust, 48 given chrysotile, 24 saline controls. Inhalation experiment: 56 Fischer rats per dust.
• Exposure: Injection: glass microfibre (Johns Manville code 100), glass wool, rock wool and slag wool (the wools as supplied and with resins extracted), compared with UICC African chrysotile. Inhalation: UICC Canadian chrysotile, glass microfibre (JM 100), glass wool, glass wool without resin, and rock wool. The respirable concentration was 10 mg per unit volume (the unit is cut off in the scan), for 35 hours a week for one year. Diameters were 0.03 to 2 µm for chrysotile and glass microfibre (geometric mean 0.3 µm) and 0.2 to 3 µm for the wools (geometric mean 0.8 µm).
• Main results:
  • Injection experiment: mesotheliomas occurred in six rats in the chrysotile group and four in the glass microfibre (JM 100) group (48 rats per group).
  • Injection experiment: five mesotheliomas occurred in the rock wool groups, three with resin and two without resin.
  • Injection experiment: a single mesothelioma occurred with glass wool.
  • Inhalation experiment: all exposed groups showed evidence of reaction to dust, but there was less in all the man-made mineral fibre groups than in the chrysotile group.
  • Inhalation experiment: reaction in the chrysotile group was greater at 12 months than at three months, while there was little change in the man-made mineral fibre groups.
• The authors' conclusion: The authors gave no formal conclusion. They stated that the injection results for chrysotile and glass microfibre were as expected from previous work, and that the remaining inhalation rats were living out their lives in dust-free conditions, so final results were pending.

Topics

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

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