Effect of chrysotile and crocidolite on the morphology and growth of rat pleural mesothelial cells

Our plain-English summary of Effect of chrysotile and crocidolite on the morphology and growth of rat pleural mesothelial cells, by M.C. Jaurand, I. Bastie-Sigeac, J. Bignon, et al (Environmental Research, 1983).

The study

• Authors: M.C. Jaurand, I. Bastie-Sigeac, J. Bignon, P. Stoebner
• Journal: Environmental Research
• Published: 1983;30(2):255-69
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The effects of the UICC asbestos fibers chrysotile A and crocidolite on the morphology and growth of rat pleural mesothelial cells were examined. The response was different according to the fiber used. Within 4 hr of treatment with 5, 10, 20, or 50 micrograms/ml of chrysotile fibers, cell morphology showed intense vacuolization, in both logarithmic and confluent cells. Following treatment of growing cells with 20 or 50 micrograms/ml of chrysotile fibers, cell spreading was also observed. Four hours after treatment of cells with 5, 10, or 20 micrograms/ml of crocidolite fibers, no such changes were seen. Vacuolization appeared later and was much less marked than for chrysotile fibers. The mesothelial cell population-doubling time of about 30 hr was not significantly altered by addition of 5 to 20 micrograms/ml of crocidolite fibers, but a concentration of 50 micrograms/ml lengthened doubling time to about 90 hr. Treatment with 5 or 10 micrograms/ml chrysotile fibers usually prolonged this time, but 20 or 50 micrograms/ml caused cell lysis. After 48 hr of incubation with both types of fiber, the proportion of mitosis was the same as in control cultures, whatever the fiber concentration, and asbestos fibers were often seen inside dividing cells.

In plain English

This laboratory study exposed rat pleural mesothelial cells to UICC chrysotile A and crocidolite asbestos. Four cell lines from four rats were treated for 48 hours with 5, 10, 20 or 50 micrograms per milliliter. Within 4 hours, chrysotile at every concentration caused intense vacuolization (small cavities inside the cells) in all cells. Crocidolite caused few or no vacuoles. In one cell strain, 74 hours after chrysotile, 29.3% of cells had two nuclei at 5 micrograms per milliliter and 37.3% at 10, versus 1.7% untreated. These chrysotile doses delayed growth by 48 or 72 hours, though not in more densely seeded cultures. The authors reported the toxicity was not permanent. At 20 the cells did not grow, and at 50 they died. Crocidolite at 5 or 10 did not significantly change cell numbers. At 50, the article's table gives a mean doubling time of 59.4 hours versus 31.0 in controls, but its abstract says about 90 hours. Fibers were often seen inside dividing cells. The authors concluded the cells were more sensitive to chrysotile than to crocidolite as regards growth and morphology.

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: Laboratory (in vitro) cell culture experiment comparing short-term treatment with two asbestos fiber types
• Who was studied: Rat pleural mesothelial cells obtained from the rat parietal pleura and cultured in France. Four cell lines grown from four different rats were used, between the 6th and 15th passages.
• Exposure: UICC chrysotile A and UICC crocidolite fibers, added 24 hours after subculturing for 48 hours at 5, 10, 20 or 50 micrograms per milliliter. DQ12 quartz was sometimes used as a reference sample.
• Main results:
  • After 4 hours with chrysotile at 5, 10, 20 or 50 micrograms per milliliter, all cells showed intense vacuolization.
  • No vacuolation was seen after 6 hours with crocidolite at 5 or 10 micrograms per milliliter. Some cells showed a few vacuoles at 20 or 50.
  • In Table 1 (strain 18), 74 hours after treatment, 29.3% of cells were binucleated (had two nuclei) with chrysotile at 5 micrograms per milliliter and 37.3% at 10, compared with 1.7% of untreated cells. The article's prose rounds this to 30% for both doses, versus 1 to 3% in controls.
  • Chrysotile at 5 or 10 micrograms per milliliter caused a 48- or 72-hour lag in cell growth. This lag was not observed when fibers were added to cultures with higher cell densities (5 x 10^5 to 6 x 10^5 cells per flask).
  • After 48 hours of treatment with chrysotile at 5 or 10 micrograms per milliliter, the number of treated growing cells was significantly lower than in control cultures (P less than 0.01).
  • With chrysotile at 20 micrograms per milliliter the cells did not grow, and at 50 they died.
  • The cytotoxicity from chrysotile was not permanent. Cell numbers 192 hours after 5 micrograms per milliliter, and 216 hours after 10, did not differ from controls. After 20 micrograms per milliliter, cell numbers at 216 hours remained lower than controls.
  • With crocidolite at 5 or 10 micrograms per milliliter, cell numbers at 48 or 72 hours did not differ significantly from controls.
  • With crocidolite at 50 micrograms per milliliter, the difference in cell numbers from controls was always significant (P less than 0.01). At 20 micrograms per milliliter, the response depended on the cell strain.
  • In crocidolite-treated cultures, Table 2 gives a mean population-doubling time of 31.0 hours in controls. It gives 31.8 hours at 5, 33.7 at 10, 35.5 at 20 and 59.4 at 50 micrograms per milliliter. The text gives a range of 44 to 216 hours at 50.
  • The article's own abstract states a different figure for crocidolite at 50 micrograms per milliliter. It says doubling time lengthened from about 30 hours to about 90 hours, which conflicts with the 59.4-hour mean in Table 2.
  • In chrysotile-treated cultures, mean population-doubling time (Table 2) was 29.7 hours in controls, 33.2 hours at 5 and 42.7 hours at 10 micrograms per milliliter. The text states the maximum increase was 120% of the control value and varied by strain.
  • After 48 hours with 50 micrograms per milliliter of fibers, 0.7 to 2% of cells were in mitosis (dividing), compared with 1 to 2% of untreated control cells. Asbestos fibers were often seen inside dividing cells.
• The authors' conclusion: The authors concluded that the rat pleural mesothelial cells were very sensitive to low doses of chrysotile. They also concluded the cells were more sensitive to chrysotile than to crocidolite as regards growth and morphology. They inferred that cells undergoing mitosis might be more sensitive to chrysotile than resting cells.
• Limitations the authors state:
  • The amount of asbestos fiber taken up by the cells was not measured.
  • The 50 micrograms per milliliter crocidolite concentration was very high and may have had non-specific effects, such as inhibiting cell adherence to the flask.
  • The experiments were short-term. The authors suggested long-term in vitro experiments would be of interest, given the different latency seen in animals.

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Crocidolite, Mesothelial Cells, UICC.

Related studies

• Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene — M.C. Jaurand, I. Bastie-Sigeac, et al. (1983)
• KGF and HGF are growth factors for mesothelial cells in pleural lavage fluid after intratracheal asbestos — I.Y. Adamson, J. Bakowska (2001)
• Comparative toxicities of different forms of asbestos on rat pleural mesothelial cells — M.C. Jaurand, I. Bastie-Sigeac, et al. (1983)
• 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)
• Sister chromatid exchanges in rat pleural mesothelial cells treated with crocidolite, attapulgite, or benzo 3-4 pyrene — S. Achard, M. Perderiset, et al. (1987)
• Increased expression of epidermal growth factor receptor in rat pleural mesothelial cells correlates with carcinogenicity of mineral fibres — S.P. Faux, C.E. Houghton, et al. (2000)

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