Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests

Our plain-English summary of Assessment of progression of asbestosis in the sheep model by bronchoalveolar lavage and pulmonary function tests, by R. Bégin, M. Rola-Pleszczynski, S. Massé, et al (Thorax, 1983).

The study

• Authors: R. Bégin, M. Rola-Pleszczynski, S. Massé, D. Nadeau, G. Drapeau
• Journal: Thorax
• Published: 1983;38(6):449-57
• Cited by: 42 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

To study the relationship between the results of bronchoalveolar lavage and pulmonary function tests during induction and progression of asbestosis, three groups of six sheep were exposed repeatedly by intratracheal injection to either saline (controls), low doses of Canadian chrysotile UICC asbestos (cumulative exposure 328 mg) (low-dose group), or high doses of the same fibres (cumulative dose 2282 mg) (high-dose group) until there was clear evidence of alveolitis from the lung biopsy specimens of all sheep of the high-dose group. During the course of this induction and for the following eight months lung biopsies, bronchoalveolar lavage and pulmonary function tests were performed at two-month intervals. At the time of initial alveolitis in the high-dose group there was no significant change in the cellularity of the bronchoalveolar lavage fluid, but static lung compliance (Cst), vital capacity (VC), arterial oxygen tension (Pao2), and diffusion capacity (DL/VA) were significantly lower than in the other groups. In the following months, as the alveolitis evolved into a fibrosing process, macrophages and neutrophils from the bronchoalveolar lavage fluid increased significantly and pulmonary function deteriorated. Proteins and enzymes in the bronchoalveolar lavage fluid also increased significantly in the high-dose group. These data show that in the sheep model of asbestosis simple tests of pulmonary function correlate well with histological changes and changes in the bronchoalveolar lavage fluid in the course of the disease and can be used to assess progression of asbestosis.

In plain English

This was an animal experiment in sheep. Eighteen male sheep were divided into three groups of six. Over the first 12 months, by injection into the windpipe, the control group received saline, a low-dose group received a cumulative 328 mg of UICC Canadian chrysotile asbestos, and a high-dose group received a cumulative 2282 mg. Every two months, for 20 months in all, the sheep had lung biopsies, lung washing (bronchoalveolar lavage) and lung function tests. The low-dose group showed no definite microscopic lung changes. However, its static lung compliance, total lung capacity and vital capacity began to differ from controls at month 16. By month 12, all high-dose sheep had definite inflammatory lung lesions (alveolitis), and scarring (interstitial fibrosis) was seen later. In the high-dose group, lung function worsened. The lavage fluid showed rising enzyme and protein levels, followed by rising cell counts. In that group, changes in several lung function measures were correlated with lavage changes, with r above 0.8 for most correlations. The authors concluded that simple lung function tests can be used to assess progression of asbestosis in the sheep model.

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 (repeated intratracheal exposure of sheep, with serial testing every two months)
• Who was studied: 18 male sheep weighing 25-50 kg at the start, in three groups of six (controls, low-dose, high-dose), followed for 20 months; one sheep per group was killed at month 12 and at month 20 for detailed study
• Exposure: UICC Canadian chrysotile asbestos fibres in saline, given by intratracheal injection: cumulative 328 mg (low-dose group) or 2282 mg (high-dose group); controls received saline. Exposure stopped after the 12th month.
• Main results:
  • High-dose group: all sheep had definite lung lesions (alveolitis) at month 12, and interstitial fibrosis was observed in the following months
  • Low-dose group: no definite microscopic changes were seen in biopsy or necropsy lung specimens
  • High-dose group: lavage fluid lactate dehydrogenase rose significantly from month 8; later, total cells, macrophages and neutrophils in the fluid increased significantly. Control and low-dose groups could not be told apart on lavage.
  • High-dose group: static lung compliance was significantly lower from month 6 onward; vital capacity changed significantly at month 12 and total lung capacity at month 16
  • Low-dose group: began to differ from controls at month 16 in static lung compliance, total lung capacity and vital capacity
  • High-dose group: gas exchange measures differed significantly from month 8. Hypoxia, rapid breathing and diffusion impairment worsened significantly from month 12 to month 20 (p less than 0.01).
  • High-dose group: changes over time in several lung function measures (compliance, total lung capacity, vital capacity, arterial oxygen, diffusion) were highly correlated with lavage changes (r greater than 0.8 for most correlations, p less than 0.01). FRC, RV and minute ventilation did not correlate with lavage changes.
• The authors' conclusion: The authors concluded that in the sheep model of asbestosis, simple lung function tests (vital capacity, diffusion capacity, arterial oxygen) correlate well with lavage fluid changes over the course of the disease and can be used to assess its progression.

Topics

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

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Pulmonary Function Test (PFT), Chrysotile, UICC, Cumulative Exposure, Biopsy, Macrophage.

Related studies

• Fibronectin and procollagen 3 levels in bronchoalveolar lavage of asbestos-exposed human subjects and sheep — R. Bégin, M. Martel, et al. (1986)
• Asbestosis: assessment by bronchoalveolar lavage and measurement of pulmonary epithelial permeability — A.R. Gellert, J.A. Langford, et al. (1985)
• Morphologic features and function of the airways in early asbestosis in the sheep model — R. Bégin, S. Massé, et al. (1982)
• Biochemical components of bronchoalveolar lavage in early experimental asbestosis of the sheep: phospholipase A2 activity, prostaglandin E2 and proteins — P. Sirois, G. Drapeau, et al. (1983)
• Asbestos-induced lung injury in the sheep model: the initial alveolitis — R. Bégin, M. Rola-Pleszczynski, et al. (1983)
• Bronchoalveolar lavage in pulmonary fibrosis: comparison of cells obtained with lung biopsy and clinical features — P.L. Haslam, C.W. Turton, et al. (1980)

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