Chromosomal aberrations induced by chrysotile and crocidolite in human lymphocytes in vitro

Our plain-English summary of Chromosomal aberrations induced by chrysotile and crocidolite in human lymphocytes in vitro, by F. Valerio, M. de Ferrari, L. Ottaggio, et al (Mutation Research, 1983).

The study

• Authors: F. Valerio, M. de Ferrari, L. Ottaggio, E. Repetto, L. Santi
• Journal: Mutation Research
• Published: 1983;122(3-4):397-402
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

The authors investigated whether two asbestos fiber types, chrysotile and crocidolite, induce chromosomal aberrations in human lymphocytes in vitro. Blood lymphocytes were obtained from 18 subjects in two groups. Chrysotile was tested in 4 men and 5 women aged 23 to 33 years, and crocidolite in 3 men and 6 women aged 24 to 37 years. UICC fibers were ultrasonicated, sterilized and added to cultures at a final concentration of 10 µg/ml, with an untreated control sample for each subject. After 72 hours of incubation, up to 100 metaphases per sample were scored for numerical changes and for chromatid and chromosome anomalies. Results were analysed with Wilcoxon's test. With chrysotile, chromatid breaks totalled 118 in treated cells versus 39 in controls (p<0.001), and chromosome breaks 25 versus 3 (p<0.05). With crocidolite, chromatid breaks were 149 versus 57 (p<0.001) and chromosome breaks 76 versus 9 (p<0.001). Changes in chromosome number and polyploidy were not significant. Rings, dicentrics and endoreduplications appeared only in crocidolite-treated cells, but their incidence was not statistically significant. A repeat chrysotile experiment with 48-hour incubation showed a significant increase in chromosome aberrations in 5 of 9 subjects, and in chromatid aberrations in 8 subjects. The authors concluded that the chromosome-type aberrations reflected a direct effect of the fibers. They stated that the mechanism and its significance for carcinogenicity need further investigation.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This laboratory study tested whether UICC chrysotile and crocidolite asbestos fibers damage chromosomes in human lymphocytes (white blood cells). Cells from 18 subjects were used, 9 for each fiber. Each subject's cells were grown for 72 hours with fibers at 10 micrograms per ml, beside an untreated sample. Gaps and breaks were scored together. With chrysotile, chromatid gaps and breaks totaled 118 in treated cells versus 39 in untreated cells, and chromosome gaps and breaks 25 versus 3. With crocidolite, the totals were 149 versus 57 and 76 versus 9. Seven of those 9 in untreated cells came from one subject professionally exposed to chemicals. These increases were statistically significant; changes in chromosome number and polyploidy were not. Rings, dicentrics and endoduplications appeared only in crocidolite-treated cells, but not at a statistically significant level. A repeat 48-hour chrysotile test showed more chromosome aberrations in 5 of 9 subjects, a statistically significant increase by a one-tailed sign test across subjects. The authors concluded that the chromosome-type damage reflected a direct effect of the fibers, whose mechanism and cancer significance need further investigation.

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) cytogenetic experiment. Cultured human lymphocytes from each subject were exposed to asbestos fibers and compared with an untreated control sample from the same subject. Gaps and breaks were scored together, without distinguishing them.
• Who was studied: Blood lymphocytes from 18 subjects in two groups. Chrysotile was tested on cells from 4 men and 5 women aged 23 to 33. Crocidolite was tested on cells from 3 men and 6 women aged 24 to 37.
• Exposure: UICC chrysotile (described as Rhodesian) and UICC crocidolite fibers, added to cultures at a final concentration of 10 micrograms per ml. Cells were incubated for 72 hours, with an additional 48-hour chrysotile experiment.
• Main results:
  • Chrysotile group (9 subjects): chromatid gaps and breaks (scored together; labeled breaks in the table) totaled 39 in control cells and 118 in treated cells (p less than 0.001). Chromosome gaps and breaks totaled 3 in control cells and 25 in treated cells (p less than 0.05).
  • Crocidolite group (9 subjects): chromatid gaps and breaks (scored together; labeled breaks in the table) totaled 57 in control cells and 149 in treated cells (p less than 0.001). Chromosome gaps and breaks totaled 9 in control cells and 76 in treated cells (p less than 0.001).
  • For both fibers, changes in chromosome number and the incidence of polyploidy were not statistically significant.
  • The largest increase after treatment with either fiber was in chromosome alterations, about 7-fold.
  • Of the 9 chromosome breaks counted in untreated control cells in the crocidolite test, 7 came from one subject who was professionally exposed to chemicals.
  • Rings, dicentrics and endoduplications were seen only in crocidolite-treated cells, but their incidence was not statistically significant.
  • Repeat chrysotile experiment in the same donors: after 48 hours, the text reports the increase in chromosome aberrations in 5 of 9 subjects. After 72 hours, chromosome aberrations were seen in 7 of 9 subjects.
  • The Figure 3 caption gives the statistical significance of the increase in chromosome alterations after 48 hours of chrysotile exposure, tested across subjects, as p less than 0.03 (one-tailed sign test; printed with the letter O in place of zero).
  • In the same repeat chrysotile experiment, chromatid aberrations were seen in 8 subjects after 48 hours and in all 9 after 72 hours. The Figure 2 caption gives the significance of the 48-hour increase in chromatid alterations as p less than 0.004 (one-tailed sign test; printed with the letter O in place of zero).
• The authors' conclusion: The authors concluded that the chromosome-type aberrations reflected a direct effect of the fibers, not merely an amplification of chromatid-type damage from the first cell division.
• Limitations the authors state:
  • The authors stated that the mechanism behind the chromosome and chromatid-type aberrations is not known.
  • The authors stated that how these aberrations form, and what they mean for carcinogenicity, still need to be investigated.

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, UICC.

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• Specificity of asbestos-induced chromosomal aberrations in short-term cultured human mesothelial cells — K. Olofsson, J. Mark (1989)
• In vitro chromosomal aberrations induced by various shapes of multi-walled carbon nanotubes (MWCNTs) — T. Sasaki, M. Asakura, et al. (2016)
• Oxygen radical-mediated mutagenic effect of asbestos on human lymphocytes: suppression by oxygen radical scavengers — L.G. Korkina, A.D. Durnev, et al. (1992)
• Induction of chromosomal aberrations in bone marrow cells of asbestotic rats — N. Fatma, S.G. Khan, et al. (1992)

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