The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study

Our plain-English summary of The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study, by N.S. Wang, M.C. Jaurand, L. Magne, et al (The American Journal of Pathology, 1987).

The study

• Authors: N.S. Wang, M.C. Jaurand, L. Magne, L. Kheuang, M.C. Pinchon, J. Bignon
• Journal: The American Journal of Pathology
• Published: 1987;126(2):343-9
• Cited by: 61 articles, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

Rat pleural mesothelial cells (PMCs) in culture at the exponential growing phase were exposed to 5 micrograms/ml of chrysotile (CH) or crocidolite (CR) asbestos fibers: the cells and their chromosomes were studied 48 hours thereafter by light, scanning, and transmission electron microscopy (LM, SEM, TEM). PMCs phagocytized both CH and CR. Mild vacuolar cytoplasmic changes by LM and a few small surface blebbings by SEM were present, mainly in cells treated with CH. Metaphase chromosomes were well separated and retained surface details by SEM in the control group. Chromosomes were frequently entangled with, adherent to, and severed or pierced by long and thin curvilinear CH with occasional chromatin fibers threading over the partly severed asbestos. Similar chromosomal changes were much less frequently found in CR-treated cells; TEM confirmed the same findings. CH and CR have different physicochemical properties and also appear to have direct, intricate, but different interactions with chromosomes, as well as the cytoplasm, of PMCs.

In plain English

This laboratory study used rat pleural mesothelial cells (cells from the lining of the chest cavity) grown in culture. The authors exposed growing cells to 5 micrograms per milliliter of UICC chrysotile A or crocidolite asbestos fibers, kept a control group without fibers, and examined the cells and their chromosomes 48 hours later with light, scanning and transmission electron microscopes. The cells took up both fiber types. Cytoplasm vacuoles and small surface blebs were seen mainly in chrysotile-treated cells. Chrysotile fibers were found in 21 of 23 groups of dividing-cell chromosomes and appeared to sever, puncture, or stick to and tangle with chromosomes. Similar obvious fiber-chromosome interactions with crocidolite were found in only 2 of 21 groups. The authors concluded that the two fiber types appear to interact directly but differently with chromosomes, and that this could support the idea that asbestos-related chromosome changes play a role in cancer. They noted that the dose was high compared with conceivable human exposure and that the meaning of the difference between the fibers was unclear.

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 examined by light, scanning and transmission electron microscopy, with an unexposed control group
• Who was studied: Rat pleural mesothelial cells grown in culture, used between 12 and 20 passages; the number of cultures is not stated apart from the counts of metaphase chromosome groups examined
• Exposure: 5 micrograms per milliliter of UICC chrysotile A or crocidolite asbestos fibers in the culture medium, with cells examined after 48 hours of incubation
• Main results:
  • There was no evidence of cell destruction, and asbestos fibers were readily found in the cytoplasm of most cells in both the chrysotile and crocidolite groups
  • Mild to moderate vacuolar changes of the cytoplasm and a few small surface blebs were found in some chrysotile-treated cells but seldom or rarely in crocidolite-treated or control cells
  • Chrysotile fibers were mostly in groups, curvilinear, with fragmented or frayed ends, and partly enveloped by or inserted into the cells. Crocidolite fibers were mostly isolated and straight and more likely to lie next to or stuck on the cells
  • In chrysotile-treated cells, chrysotile fibers were found in 21 of 23 groups of metaphase chromosomes and appeared to sever, puncture, or adhere to and mingle with chromosomes, causing deformities; occasionally chromatin fibers appeared to thread over the asbestos fiber in a partly severed chromosome
  • In crocidolite-treated cells, most fibers were located next to or between chromosomes; obvious fiber-chromosome interactions similar to those with chrysotile were found in only 2 of 21 groups of metaphase chromosomes
  • Polyploidy (extra sets of chromosomes) was noted in all groups but more in the chrysotile-treated groups
  • By transmission electron microscopy, fibers were mostly next to the chromosomes but occasionally within a chromosome, especially in the chrysotile-treated group. Fibers inside the nucleus were found only very rarely, in chrysotile-treated cells
• The authors' conclusion: The authors concluded that chrysotile and crocidolite appear to have direct, intricate, but different interactions with the chromosomes and cytoplasm of these cells. They suggested that asbestos fibers can cause chromosomal changes by direct physical damage, and that their findings could explain and further support the idea that asbestos-related chromosomal changes play a role in asbestos carcinogenesis
• Limitations the authors state:
  • The dose used was high for both chrysotile and crocidolite compared with conceivable human exposure
  • The significance of the difference in how often chrysotile and crocidolite caused chromosomal alterations is unclear
  • Possible interference with the cell-division spindle could not be evaluated because spindle structures were dissolved during preparation
  • Precise interpretation of other chromosomal details was difficult, partly because the preparations were not uniform
  • The fiber-chromosome interactions might have occurred during processing, including air-drying, although the authors considered this unlikely

Topics

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Chrysotile, Crocidolite, Transmission Electron Microscopy (TEM).

Related studies

• Induction of metaphase and anaphase/telophase abnormalities by asbestos fibers in rat pleural mesothelial cells in vitro — M. Yegles, L. Saint-Etienne, et al. (1993)
• Phagocytosis of chrysotile fibers by pleural mesothelial cells in culture — M.C. Jaurand, H. Kaplan, et al. (1979)
• Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells — M.C. Jaurand, L. Kheuang, et al. (1986)
• Metaphase and anaphase analysis of V79 cells exposed to erionite, UICC chrysotile and UICC crocidolite — L.D. Palekar, J.F. Eyre, et al. (1987)
• 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)
• Analysis of cell cycle disruptions in cultures of rat pleural mesothelial cells exposed to asbestos fibers — V. Levresse, A. Renier, et al. (1997)

Browse more research in The American Journal of Pathology, or return to medical research.