Pulmonary toxicity of wollastonite in vivo and in vitro

Our plain-English summary of Pulmonary toxicity of wollastonite in vivo and in vitro, by E. Tátrai, Z. Kováciková, M. Brózik, et al (Journal of Applied Toxicology, 2004).

The study

• Authors: E. Tátrai, Z. Kováciková, M. Brózik, E. Six
• Journal: Journal of Applied Toxicology
• Published: 2004;24(2):147-54
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pulmonary toxicity of wollastonite has been studied in both in vivo long-term sequential and in vitro methods in Sprague-Dawley rats. Wollastonite was administered by intratracheal instillation and the lungs were examined after 1, 3 and 6 months by morphological methods. UICC crocidolite was applied as the positive control. In addition, the effects of both fibres were examined in primary cultures of pulmonary alveolar macrophages and type II pneumocytes to determine the effects of the fibres on the membranes of these cells, the activity of Cu,Zn/superoxide dismutase and the redox system and the release of proinflammatory peptides: macrophage chemoattractant protein-1 (MCP-1) and macrophage inhibitory protein-1alpha (MIP-1alpha). By the end of six months wollastonite had induced mild pulmonary interstitial fibrosis, whereas crocidolite induced progressive interstitial fibrosis as a function of time. The membranes of macrophages and pneumocytes were disrupted at the lowest concentration of crocidolite. The activity of enzymes of the redox system and cytoplasmic superoxide dismutase significantly decreased with crocidolite. Wollastonite decreased only the activity of gamma-glutamyl transpeptidase and glutathione peroxidase. Crocidolite induced expression of the proinflammatory peptides at the lowest concentration (1 micro g ml(-1)) but wollastonite increased production of these peptides only at medium and high concentrations (5 and 10 micro g ml(-1)). These results underline the importance of further human epidemiological studies and the need for the determination of a hygienic standard.

Copyright 2004 John Wiley & Sons, Ltd.

In plain English

This was an animal experiment in male Sprague-Dawley rats, with a live-animal part and a cell-culture part. It compared wollastonite, a fibrous calcium silicate mineral used as an asbestos replacement, with UICC crocidolite asbestos. Rats received a single 1 mg dose of either fibre, or saline, into the windpipe, and their lungs were examined 1, 3 and 6 months later. Wollastonite caused mild chronic inflammation with a minimal increase in connective-tissue (argyrophilic) fibres by one month (Wagner grade 3 to 4), and this did not progress at 3 and 6 months. Crocidolite caused intense inflammation and fibrosis that became more intense over time, reaching Wagner grade 8. Rat lung cells were also exposed in culture to 1, 5 or 10 micrograms per millilitre. Crocidolite lowered the activity of all enzymes measured and damaged cell membranes at the lowest concentration. Wollastonite lowered two enzymes in one cell type and reduced membrane staining only at the highest concentration. It also raised two inflammatory signalling proteins less than crocidolite did. The authors concluded that wollastonite is less cytotoxic than crocidolite, and they called for further human studies and a hygienic standard.

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: long-term in vivo study with sequential sacrifice in rats, plus in vitro study in primary cultures of rat lung cells; UICC crocidolite as positive control, saline as negative control
• Who was studied: Male Sprague-Dawley rats. In vivo: five animals per group for light microscopy and three per group for electron microscopy, killed at 1, 3 or 6 months. In vitro: alveolar macrophages and type II pneumocytes isolated from rats, in three series of experiments using six animals each. The study was carried out in Hungary.
• Exposure: Wollastonite (supplied from Guangzhou, China) and UICC crocidolite. In vivo: single intratracheal instillation of 1 mg per animal; controls received 1 ml physiological saline. In vitro: 1, 5 and 10 µg per ml for 20 hours.
• Main results:
  • Wollastonite-treated rats at 1 month: multifocal, mild chronic inflammation in the interstitium with a minimal increase in argyrophilic fibres in the interalveolar septa (Wagner's classification 3 to 4)
  • Wollastonite-treated rats: the inflammation did not progress, fibrosis stayed at the same degree at 3 and 6 months, and the regional lymph nodes showed no changes
  • Crocidolite-treated rats: very intense multifocal interstitial inflammation at 1 month (Wagner 6), which became more intense by 3 and 6 months with fibrosis at Wagner's classification 8
  • Electron microscopy at 6 months, crocidolite-treated rats: collagen fibres accumulated in the interalveolar septa and under the epithelium and endothelium
  • Electron microscopy at 6 months, wollastonite-treated rats: collagen fibrils were only very rarely seen
  • Cultured type II pneumocytes: wollastonite decreased the activity of glutathione peroxidase (GSH-Px) and gamma-glutamyl transpeptidase (GGT), P less than 0.01
  • Cultured alveolar macrophages exposed to wollastonite: enzyme activity increased with dose
  • Cultured cells exposed to crocidolite: activity of all enzymes examined decreased in both macrophages and pneumocytes
  • Lectin staining, crocidolite: membranes of both cell types fragmented irregularly at 1 µg per ml
  • Lectin staining, wollastonite: decreased membrane reaction with MPA only at the highest concentration
  • Inflammatory signalling proteins, crocidolite: MIP-1α production increased significantly, especially in pneumocytes at the medium and high concentrations
  • Inflammatory signalling proteins, wollastonite: MIP-1α in alveolar macrophages increased significantly (P less than 0.05)
  • Comparison: wollastonite induced expression of MCP-1 and MIP-1α to a lesser extent than crocidolite
• The authors' conclusion: The authors concluded that their data suggest wollastonite, a potential asbestos substitute, is less cytotoxic than crocidolite. They said the results underline the importance of further human epidemiological studies and the urgency of setting a hygienic standard.

Topics

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

Medical terms in this study, explained in our Lexicon: Wollastonite, UICC, Crocidolite, Alveolar Macrophage, Superoxide, Macrophage, Interstitial Fibrosis, Glutathione (GSH).

Related studies

• Red blood cell damage by wollastonite: in vitro study — M. Aslam, M.J. Arif, et al. (1995)
• Fibrogenic effect of wollastonite compared with asbestos dust and dusts containing quartz — E.E. McConnell (1995)
• Wollastonite fibers in vitro generate reactive oxygen species able to lyse erythrocytes and activate the complement alternate pathway — M. Governa, L. Camilucci, et al. (1998)
• Wollastonite exposure and lung fibrosis — M.S. Huuskonen, A. Tossavainen, et al. (1983)
• Investigation of the biodurability of wollastonite and xonotlite — B. Bellmann, H. Muhle (1994)
• Fibrogenic effect of wollastonite compared with asbestos dust and dusts containing quartz — M. Cambelová, A. Juck (1994)

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