Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene

Our plain-English summary of Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene, by M.C. Jaurand, I. Bastie-Sigeac, L. Magne, et al (Environmental Health Perspectives, 1983).

The study

• Authors: M.C. Jaurand, I. Bastie-Sigeac, L. Magne, M. Hubert-Habart, J. Bignon
• Journal: Environmental Health Perspectives
• Published: 1983;51:159-65
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cultures of rat pleural mesothelial cells (PMC) were exposed to nonlethal doses of UICC chrysotile A. The morphology was studied by optical and electron microscopy. The consequences of chrysotile ingestion on the rate of pinocytosis of horseradish peroxidase (HPR) metabolism and benzo-3-4-pyrene (BP) were studied. Nonlethal doses of chrysotile (5 micrograms/mL) induced a time-dependent vacuolation of PMC; a dose-dependent inhibition of the vacuolation was observed when PMC were pretreated with DMSO. The origin of the vacuoles is not clear, but some features of autophagy and lysosomal storage were observed. Chrysotile fibers did not modify the rate of pinocytosis of HRP. Similarly, the metabolism of BP was unchanged when BP and chrysotile were both added to the culture medium or when PMC were preincubated with the fibers 24 hr prior to the addition of BP.

In plain English

This was a laboratory study of rat pleural mesothelial cells (cells from the lining of the chest cavity) grown in culture and exposed to UICC chrysotile A asbestos fibers at doses chosen not to kill the cells. After 20 hours, 99 ± 1% of cells exposed to 5 micrograms per mL excluded a viability dye, compared with 73 ± 14% at 50 micrograms per mL. At 5 micrograms per mL, chrysotile caused clear bubbles (vacuoles) to form inside the cells. After 20 hours, 80.2 ± 20% of cells contained them, averaging 6.6 ± 3.7 vacuoles per cell. Under the electron microscope, fibers were seen inside engulfing (phagocytic) vacuoles, while the large vacuoles were generally empty. Pretreating the cells with the solvent DMSO reduced vacuole formation in a dose-dependent way. Chrysotile did not change how fast the cells took up a test protein (horseradish peroxidase). At 2 micrograms per mL, it did not significantly change how the cells processed the hydrocarbon benzo-3-4-pyrene. The authors concluded that nonlethal chrysotile doses caused structural abnormalities in these cells but left these aspects of metabolism unchanged. They stated that the mechanism of the vacuoles was not defined.

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: in vitro laboratory (cell culture) experiment
• Who was studied: Cultured rat pleural mesothelial cells (PMC), used at confluency between the 8th and 20th passage; several cell strains
• Exposure: UICC chrysotile A fibers dispersed by sonication. Viability was tested at a range of concentrations; 5 µg/mL was used for the morphology and HRP experiments and 2 µg/mL for the benzo-3-4-pyrene (BP) metabolism experiments. DMSO pretreatment was also tested.
• Main results:
  • After 20 hr, 5 µg/mL chrysotile did not highly modify cell viability: 99 ± 1% of cells were unstained by trypan blue and LDH released was 7.3 ± 4.5%. At 50 µg/mL the figures were 73 ± 14% and 21.1 ± 16.9% (Table 1).
  • With 5 µg/mL chrysotile, 80.2 ± 20% of PMC contained vacuoles after 20 hr (mean of four cell strains)
  • The mean number of vacuoles per PMC was 3.0 ± 2.6 after 8 hr and 6.6 ± 3.7 after 20 hr of incubation with the fibers
  • Electron microscopy after 2 hr showed phagocytic vacuoles containing chrysotile fibers and large regular vacuoles that were generally empty or contained traces of membrane whorls
  • DMSO added 1 hr before chrysotile produced a dose-dependent inhibition of vacuolation
  • Adding 5 µg/mL chrysotile did not change the rate of pinocytosis of horseradish peroxidase (HRP)
  • After 24 hr, 60% of BP was metabolized by PMC. With 2 µg/mL chrysotile added together with BP, the fraction metabolized was not significantly different.
  • Pretreating PMC with chrysotile did not change the proportions of water-soluble and organic-soluble radioactivity (Table 3): BP alone 37% and 63%; BP plus chrysotile 40% and 60%; chrysotile 24 hr before BP 37% and 63%; chrysotile 4 hr before BP 35% and 65%.
• The authors' conclusion: The authors concluded that nonlethal concentrations of UICC chrysotile A fibers induced morphological abnormalities in rat pleural mesothelial cells in culture. They also concluded that the rate of HRP pinocytosis and the metabolism of BP were unchanged.
• Limitations the authors state:
  • The authors stated that the significance and mechanism of the large empty vacuoles were not clear and that further studies were needed
  • The authors stated that the reason DMSO inhibited vacuolation was not clear

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, Mesothelial Cells, UICC.

Related studies

• In vitro transformation of rat pleural mesothelial cells by chrysotile fibres and/or benzo[a]pyrene — M.J. Paterour, J. Bignon, et al. (1985)
• Effects of crocidolite and chrysotile asbestos on cellular uptake and metabolism of benzo(a)pyrene in hamster tracheal epithelial cells — B.T. Mossman, A. Eastman, et al. (1983)
• Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells — M.C. Jaurand, L. Kheuang, et al. (1986)
• Effect of chrysotile asbestos and silica on the microsomal metabolism of benzo(a)pyrene — C. Kandaswami, P.J. O'Brien (1983)
• Enhancement of benzo[a]pyrene mutagenicity by chrysotile asbestos in rat liver epithelial cells — B. Reiss, C. Tong, et al. (1983)
• Study of the cell-transforming ability of amosite and crocidolite asbestos and the ability to induce changes in the metabolism and macromolecular binding of benzo(a)pyrene in C3H10T1/2 cells — A. Poole, R.C. Brown, et al. (1983)

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