Study of inflammatory responses to crocidolite and basalt wool in the rat lung

Our plain-English summary of Study of inflammatory responses to crocidolite and basalt wool in the rat lung, by Z. Adamis, T. Kerényi, K. Honma, et al (Journal of Toxicology and Environmental Health. Part a, 2001).

The study

• Authors: Z. Adamis, T. Kerényi, K. Honma, M. Jäckel, E. Tátrai, G. Ungváry
• Journal: Journal of Toxicology and Environmental Health. Part a
• Published: 2001;62(5):409-15
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The subacute effects of crocidolite and basalt wool dusts were studied by nmeans of biochemical, morphological. and histological methods 1 and .3 mo after intrabronchial instillation. The cell count, protein and phospholipid contents, and lactate dehydrogenase (LDH) activity were determined in the bronchoalveolar lavage (BAL). Both types of fibers induced a prolonged inflammatory reaction in the lung. All the parameters studied in the experimental groups were more markedly elevated after 3 mo. Relative to the control, the protein and LDH values were increased three- to fivefold, the phospholipid content twofold, and the number of free cells in the BAL exceeded the control level up to ninefold. The inflammatory responses to crocidolite and basalt wool in the lung did not differ significantly. In spite of this, basalt wool is recoinmended as an asbestos substitute, as the use of this man-nade fiber may result in a significantly lower release of dust than that from crocidolite.

In plain English

This was an animal experiment in male Wistar rats comparing the lung effects of crocidolite (blue asbestos) with basalt wool, a man-made mineral fiber. Each fiber-treated rat received a single 2 mg dose of either fiber in saline, placed directly into the right lung. Control rats received saline only. The authors examined fluid rinsed from the lungs (bronchoalveolar lavage) and lung tissue 1 and 3 months later. Both fibers produced a prolonged inflammatory reaction. Measures of cell damage, protein and phospholipids in the lung fluid were significantly higher than in controls and rose further by 3 months. Free cells in the lung fluid were about double the control level after 1 month and five- to ninefold higher after 3 months. Tissue showed alveolitis, foreign-body granulomas, peribronchitis and adenoma-like proliferation of the bronchi. The two fibers did not differ significantly in the size of these measured effects. The authors stated that this does not prove basalt wool has the same consequences as crocidolite. They recommended basalt wool as a crocidolite substitute because, they stated, it produces less fiber dust, but this study did not measure dust release. They called for further testing of its potential carcinogenicity.

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 experiment: single instillation of fibers into the rat lung, with examination at 1 and 3 months
• Who was studied: Male Wistar rats weighing 230 to 260 g, divided into six groups of six animals (crocidolite, basalt wool and saline controls). The location and dates of the experiment are not stated.
• Exposure: A single dose of 2 mg of UICC standard crocidolite or of basalt wool (made from basalt, dolomite and blast-furnace slag, with a resin or oil surface coating), suspended in 0.2 ml saline and placed into the right lower lung lobe. Basalt wool fibers were 3.5 to 4.5 µm in diameter, about 10 times thicker than crocidolite. Controls received saline only.
• Main results:
  • In both fiber groups, lactate dehydrogenase (LDH, a marker of cell damage), protein and phospholipid levels in the lung fluid were significantly higher than in controls, and they were higher at 3 months than at 1 month.
  • Relative to controls, protein and LDH values in the fiber-treated rats were increased three- to fivefold.
  • There was no significant difference between crocidolite and basalt wool in the size of the measured effects.
  • In both treated groups, free cell counts in the lung fluid were double the control level after 1 month and five- or ninefold after 3 months.
  • Mean free cells (millions): controls 0.91 ± 0.1; crocidolite 2.2 ± 0.5 at 1 month and 5.4 ± 1.1 at 3 months; basalt wool 2.7 ± 0.6 at 1 month and 8.5 ± 1.5 at 3 months.
  • At 3 months, the share of leukocytes among lung-fluid cells was significantly increased: 23% with crocidolite and 24% with basalt wool, compared with 13% in controls.
  • Tissue examination showed monocytic-leukocytic alveolitis after 1 month in rats given either fiber.
  • The most frequent tissue change with either fiber was adenoma-like proliferation of the bronchi with chronic inflammation. Foreign-body granulomas around fibers and lymphoplasmocytic peribronchitis were also seen.
• The authors' conclusion: The authors concluded that both fibers induced a prolonged inflammatory reaction in the lung. They recommended basalt wool to replace crocidolite on the grounds that processing and using it produces less fiber dust than asbestos. This study did not measure dust release.
• Limitations the authors state:
  • The authors stated that the lack of a significant difference does not sufficiently prove that inhaling basalt wool leads to the same consequences as inhaling crocidolite.
  • The authors stated that further toxicological testing of basalt wool fibers is needed, particularly for potential carcinogenicity.

Topics

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

Medical terms in this study, explained in our Lexicon: Crocidolite, Lactate Dehydrogenase (LDH), Bronchoalveolar Lavage (BAL).

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