Biological Effects of Chrysotile

Our plain-English summary of Biological Effects of Chrysotile, by M.C. Jaurand, J. Bignon, A. Gaudichet, et al (1978).

The study

• Authors: M.C. Jaurand, J. Bignon, A. Gaudichet, L. Magne, A. Oblin
• Published: Environmental Research 17:216-227. Received September 23, 1977. (1978)
• Type of article: Journal article
• 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 rabbit study tested whether UICC A chrysotile asbestos became more toxic after sulfur dioxide (SO2) was sorbed onto the fibers. In the animal experiments, rabbits received one injection of 10 mg of either natural or SO2-sorbed chrysotile into the trachea. Lung-wash cells were collected 68 hours later. Both chrysotile groups yielded fewer harvested cells than controls. The two chrysotile groups did not differ significantly in viable cells, and oxygen consumption was not changed compared with controls. In the SO2-sorbed group compared with the natural-chrysotile group, the authors reported about 45% higher acid phosphatase and about 37% higher LDH enzyme activity, though the article's table shows LDH means of 56.9 (natural) and 95.8 (SO2-sorbed), which do not match the 37% figure. In laboratory-dish experiments, chrysotile lowered macrophage viability by 38% and raised enzyme release versus controls, equally for both fiber types. Both types caused the same red blood cell damage. The authors concluded that, with a low dose and short exposure, the results confirmed chrysotile toxicity but did not demonstrate a synergistic effect. Parts of the scanned text are unreadable.

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 with in vivo (rabbit) and in vitro (rabbit alveolar macrophages and red blood cells) tests comparing natural and SO2-sorbed chrysotile
• Who was studied: Rabbits (EC 601 EVIC CEBA, France), plus alveolar macrophages obtained by lung washing and red blood cells from the ear vein. The laboratories were in Créteil and Paris, France. Group sizes in the tables are partly illegible in the scan.
• Exposure: UICC A chrysotile fibers shorter than 100 micrometers, either natural or after SO2 sorption. In vivo, animals received a single intratracheal injection of 10 mg of fibers in 1.2 ml of saline, compared with a saline-injected control group and an uninjected control group.
• Main results:
  • In vivo, the number of harvested lung-wash cells decreased in both the chrysotile and the SO2-sorbed chrysotile groups compared with controls.
  • In vivo, there was no significant difference between the two chrysotile groups in the number of viable cells or in the nature of the cells harvested.
  • In vivo, oxygen consumption of the alveolar macrophages was not modified compared with controls.
  • The discussion states that LDH activity rose by about 37% and acid phosphatase activity by about 45% in the SO2-sorbed chrysotile group compared with the natural chrysotile group.
  • Table 2 prints mean LDH activity of 73 in controls, 56.9 in the natural chrysotile group and 95.8 in the SO2-sorbed chrysotile group. This does not match the about 37% LDH increase stated in the discussion.
  • Lung tissue examined under the microscope showed light alveolar type 2 cell hyperplasia, a moderate amount of alveolar exudate and no diffuse interstitial fibrosis. Which group this refers to is not clear in the damaged scan.
  • In vitro, chrysotile fibers decreased alveolar macrophage viability by 38% and increased cellular enzyme release compared with controls.
  • In vitro, alveolar macrophages showed the same results with the two kinds of chrysotile fibers.
  • With rabbit red blood cells, hemolysis and potassium (K+) leakage were identical for the natural and SO2-sorbed chrysotile groups.
• The authors' conclusion: The authors concluded that, under their specific conditions, the results confirmed chrysotile toxicity, but a possible synergistic effect of SO2 and chrysotile was not demonstrated. They suggested that the failure to detect greater differences may be due to the chemical form of the sorbed SO2.
• Limitations the authors state:
  • The experiments used a low dose of chrysotile and a short exposure time.
  • In the in vitro experiments, the decrease in cell viability may have hidden the enzyme differences seen in vivo.

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, UICC, Macrophage, Synergistic Effect.

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