Biochemical changes in guinea pig lungs due to amosite asbestos

Our plain-English summary of Biochemical changes in guinea pig lungs due to amosite asbestos, by V. Misra, Q. Rahman, P.N. Viswanathan (Environmental Research, 1978).

The study

• Authors: V. Misra, Q. Rahman, P.N. Viswanathan
• Journal: Environmental Research
• Published: 1978;16(1-3):58-61
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

In this animal experiment from Lucknow, India, the authors injected 50 mg of amosite asbestos dust into the windpipes of thirty-five adult guinea pigs and examined six at each of 40, 80, 120 and 160 days against controls. The authors' text reported that collagen rose 40% at 120 days and 65% at 160 days, glucosamine rose 24% at 160 days, and sialic acid was 50% higher at 40 days, then fell, then reached 2.75 times the control value. It reported that lung carbonic anhydrase rose at first, then fell 27% at 120 days and 18% at 160 days, and that at 160 days serum bicarbonate fell 53% and chloride rose 200%. The article's own tables, as scanned, give different figures for several of these, including the 120-day collagen, glucosamine, sialic acid and 120-day enzyme changes. In laboratory tests on normal lung tissue, all six dusts tested reduced the enzyme's activity, and chrysotile reduced it most. The authors concluded that this enzyme is a target of asbestos toxicity and may be involved in asbestos workers' breathing impairment.

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 (intratracheal injection of dust in guinea pigs), plus in vitro tests of dusts on lung homogenates
• Who was studied: Thirty-five adult guinea pigs from the ITRC animal colony (Industrial Toxicology Research Centre, Lucknow, India), with six animals sacrificed at each interval. The in vitro tests used pooled lung homogenates from two normal guinea pigs.
• Exposure: A single intratracheal injection of 50 mg amosite dust in 1.5 ml normal saline, with examination at 40, 80, 120 and 160 days. In vitro, 50 mg each of amosite, anthophyllite, chrysotile, mica, kaolin and talc.
• Main results:
  • In the amosite-injected guinea pigs, lung protein content did not change significantly at any stage
  • In the injected guinea pigs, the text reports that collagen increased only marginally up to 80 days, then by 40% at 120 days and 65% at 160 days. Table 1 as scanned gives 9.47 against a control of 5.24 at 120 days, which does not match 40%.
  • In the injected guinea pigs, the text reports a 24% glucosamine increase at 160 days. Table 1 as scanned gives 0.538 against a control of 0.155, which does not match.
  • In the injected guinea pigs, the text reports that sialic acid was 50% higher at 40 days, near control values at 80 days, and lower at 120 days. It was 2.75-fold the control value at the later stage, but Table 1 as scanned gives 1.809 against a control of 0.477 at 160 days.
  • In the injected guinea pigs, the text reports lung carbonic anhydrase activity 45% higher at 40 days and 15% higher at 80 days. At 120 days, it reports a 27% decrease, with serum bicarbonate 10% lower and serum chloride 104% higher (P less than 0.01). Table 2 as scanned gives 2.94 against a control of 4.26 for the enzyme at 120 days, which does not match 27%.
  • In the injected guinea pigs at 160 days, the text reports serum bicarbonate 53% lower (P less than 0.01), serum chloride 200% higher (P less than 0.001), and carbonic anhydrase 18% lower
  • In vitro, all the dusts inhibited carbonic anhydrase in both sucrose and water homogenates. In sucrose, the order of inhibition was chrysotile, anthophyllite, amosite, mica, kaolin and talc.
  • In vitro, silicic acid release was higher for chrysotile and anthophyllite. There was no quantitative correlation between silicic acid formation and enzyme inhibition, but a qualitative relation was apparent.
• The authors' conclusion: The authors concluded that lung carbonic anhydrase is a target of asbestos toxicity and may be involved in the respiratory impairment seen in asbestos workers. They also concluded that the changes in sialic acid, hexosamine and glucuronic acid support the view that lung cell membranes are among the targets of asbestos toxicity.
• Limitations the authors state:
  • The authors stated that little emphasis can be placed on the early-stage findings because of macrophage proliferation and changes in cellularity
  • The authors stated they could not yet decide whether sialic acid turnover is increased or whether it is released from membrane structures

Topics

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

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

Related studies

• Biochemical changes and pulmonary response of guinea pigs to asbestos dust — J. Singh, M.U. Beg, et al. (1976)
• Pathologic changes in the small airways of the guinea pig after amosite asbestos exposure — D. Filipenko, J.L. Wright, et al. (1985)
• Biochemical mechanisms in asbestos toxicity — Q. Rahman, B. Das, et al. (1983)
• Rapid short-term clearance of chrysotile compared with amosite asbestos in the guinea pig — A. Churg, J.L. Wright, et al. (1989)
• Development of asbestos bodies on amosite, chrysotile and crocidolite fibres in guinea-pig lungs — S.K. Botham, P.F. Holt (1971)
• Lung cell reactions in guinea pigs after inhalation of asbestos (amosite) — M. Sjöstrand, R. Rylander, et al. (1989)

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