Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells

Our plain-English summary of Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells, by M.C. Jaurand, J. Bignon, A. Gaudichet, et al (Environmental Research, 1978).

The study

• Authors: M.C. Jaurand, J. Bignon, A. Gaudichet, L. Magne, A. Oblin
• Journal: Environmental Research
• Published: 1978;17(2):216-27
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An experimental study has been carried out using different biological and biochemical in vivo and in vitro tests for assessing the toxicity of natural UICC (A) chrysotile and SO2-sorbed UICC (A) chrysotile and for detecting a possible synergistic effect. For in vivo studies, rabbits received an intratracheal injection of chrysotile fibers suspended in physiological saline (PS). The control group received only PS; all animals were sacrificed after 68 hr. The alveolar free cells were harvested by pulmonary lavage. The results have shown that chrysotile induces a decrease in the free cell population but there was no significant difference in the number of viable cells or in the nature of cells harvested between the two chrysotile groups. Enzymatic activities of the alveolar macrophages from animals injected with SO2-sorbed chrysotile showed a significant increase of the enzymes LDH and acid phosphatases. The LDH increase could be related to the affinity of the enzyme regarding some chemical forms of SO2. In vitro studies using alveolar macrophages harvested by pulmonary lavage have shown no differences between the two chrysotile groups when cell viability and enzyme release were studied. The toxic effect was due to chrysotile fibers (decrease of 38% in cell viability and increase in cellular enzyme release when compared with control). When rabbit red blood cells were used, both natural and SO2 chrysotile fibers showed the same hemolytic activity. The failure to detect high differences between the two chrysotile groups may be related to the chemical form of sorbed SO2.

In plain English

In this animal and laboratory experiment, the authors tested whether UICC A chrysotile asbestos that had absorbed sulfur dioxide (SO2), an air pollutant, was more harmful than untreated chrysotile. Rabbits received one injection into the windpipe of 10 mg of either fiber type, and a control group received salt water. After 68 hours, cells were washed out of the lungs and studied. Both chrysotile groups yielded fewer cells than controls, but cell viability and oxygen use did not differ. The lungs showed mild inflammation with some fibrous nodules and no diffuse interstitial fibrosis. Macrophages from rabbits given SO2-treated chrysotile had higher LDH and acid phosphatase enzyme activity. In laboratory dishes, rabbit macrophage viability fell to 47% with chrysotile and 41% with SO2-treated chrysotile, against 73% in controls. The two fiber types did not differ in enzyme release or in damage to rabbit red blood cells. The authors concluded that, with a low dose and short exposure, the results confirmed chrysotile toxicity but did not demonstrate a combined (synergistic) effect.

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 intratracheal injection in rabbits, examined after 68 hours) combined with in vitro tests on rabbit alveolar macrophages and red blood cells
• Who was studied: Rabbits, used for the in vivo injection experiments and as the source of alveolar macrophages (by lung washing) and red blood cells (from the ear vein). Group sizes varied by test, for example 14 control, 7 chrysotile and 11 SO2-chrysotile animals in the in vivo enzyme measurements.
• Exposure: UICC A chrysotile, either natural or after SO2 sorption, with fibers under 100 micrometres long. In vivo, 10 mg was injected into the trachea in 1.2 ml of saline. In vitro, 75 micrograms per ml was added to macrophages, and concentrations such as 0.75 mg per ml were used with red blood cells. Quartz was used for comparison in the macrophage tests.
• Main results:
  • In vivo, fewer cells were recovered from the lungs in both the chrysotile and SO2-chrysotile groups than in saline controls. Mean counts were 40 x 10^6 for controls, 23 x 10^6 for chrysotile (P less than 0.05) and 20 x 10^6 for SO2 chrysotile (P less than 0.02). The authors described this as a decrease of about 43%.
  • In vivo, macrophage viability and the volume of washing fluid recovered did not differ among the saline control, chrysotile and SO2-chrysotile groups.
  • In vivo, oxygen consumption of the macrophages did not differ significantly among the three groups.
  • Lungs of animals examined at 68 hours showed mild peribronchiolar and centriacinar inflammatory lesions with some giant cells and fibrous nodular reaction, and no diffuse interstitial fibrosis.
  • In vivo, macrophage LDH activity was higher in the SO2-chrysotile group than in controls (P less than 0.02) and than in the chrysotile group (P less than 0.01). Means were 95.8 for SO2 chrysotile, 70.3 for controls and 56.9 for chrysotile, in mU per 10^6 cells per ml. Acid phosphatases showed the same trend (means 14.2, 8.1 and 9.8; P less than 0.02 compared with control). Three other lysosomal enzymes were unchanged.
  • In vitro, after 20 hours, macrophage viability was 47% with chrysotile and 41% with SO2 chrysotile, compared with 73% in controls (P less than 0.001). Viability was 23% with quartz at the same concentration. The table lists 3 cases for SO2 chrysotile.
  • In vitro, both chrysotile types significantly increased LDH activity in the culture medium, and lysosomal enzyme activities were three- or fourfold higher. There was no difference between the two chrysotile groups.
  • With rabbit red blood cells, potassium and hemoglobin release at 90 minutes did not differ between natural chrysotile and SO2 chrysotile.
• The authors' conclusion: The authors concluded that, under their specific conditions, the results confirmed chrysotile toxicity, but a possible synergistic effect of SO2 sorption was not demonstrated. They suggested that the lack of larger differences may be related 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 drop in cell viability may have hidden the enzyme differences seen in vivo.

Topics

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

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

Related studies

• In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene — M.C. Jaurand, L. Magne, et al. (1981)
• Biological effects of chrysolite after SO2 sorption. iii. effects on the biochemical components of alveolar washing — A. Oblin, J.M. Warnet, et al. (1978)
• Activation of alveolar macrophages and peripheral red blood cells in rats exposed to fibers/particles — F. Afaq, P. Abidi, et al. (1998)
• In vitro biodegradation of chrysotile fibres by alveolar macrophages and mesothelial cells in culture: comparison with a pH effect — M.C. Jaurand, A. Gaudichet, et al. (1984)
• Effects of chrysotile on a lysosomal enzyme preparation and on the hydrolytic enzyme activity of cultured alveolar macrophages — R. Desai, R.J. Richards (1983)
• Effects of asbestos and beryllium on release of alveolar macrophage enzymes — K.Y. Kang, D. Bice, et al. (1979)

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