Refractory ceramic fibers (RCFs) induce germline aneuploidy in Drosophila oocytes

Our plain-English summary of Refractory ceramic fibers (RCFs) induce germline aneuploidy in Drosophila oocytes, by C.J. Osgood (Mutation Research, 1994).

The study

• Author: C.J. Osgood
• Journal: Mutation Research
• Published: 1994;324(1-2):23-7
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mineral fibers are ubiquitous in the natural environment and are widely used in industry in such applications as insulators. We have previously shown that asbestos fibers induce aneuploidy in oocytes of Drosophila melanogaster; here we extend those studies by testing refractory ceramic fibers (RCFs) for their mutagenicity to germ cells. The results establish that the tested RCFs are inducers of aneuploidy following feeding of adult females. A subset of the RCFs were also effective following larval feeding. Our results suggest that RCFs, like certain asbestos fibers, may pose a hazard to germ cells.

In plain English

In this laboratory experiment on fruit flies (Drosophila melanogaster), the author tested whether four refractory ceramic fibers (RCFs), used in industry as insulation, cause aneuploidy (eggs with a missing or extra X chromosome) in females. Chrysotile asbestos served as the positive control. Females either ate fiber slurries for three days as adults or were raised as larvae on food containing fibers. Their offspring were checked for eye colors that signal a lost or gained chromosome. After adult feeding, all fibers significantly raised the rate of such offspring, generally 2 to 3 times the control rate: control 0.02%, RCFs 0.052% to 0.076%, chrysotile 0.070%. The author called the effects modest. After larval feeding, only RCF-1 and RCF-3 had significant effects. RCF-2 and RCF-4 did not, even at a higher dose. The author noted that actual fiber consumption was not measured. The author concluded that RCFs may pose a threat as inducers of aneuploidy, at least in fruit-fly female germ cells. The author added that, to the extent fly results apply to higher organisms, some concern may be appropriate for workers exposed to high levels of mineral fibers.

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: a laboratory genetic test (the ZESTE test) in fruit flies for chromosome loss and gain in egg cells, with negative (water or sucrose water) and positive (chrysotile asbestos) controls
• Who was studied: Female fruit flies (Drosophila melanogaster). Some were fed as adults, 50 females per bottle for 3 days. Others were fed throughout larval development. Their offspring were collected in three broods and counted: 12,738 to 59,512 offspring per group.
• Exposure: The test fibers were four refractory ceramic fibers, RCF-1 to RCF-4. RCF-4 is the furnace-heated 'after service' form of RCF-2. Chrysotile asbestos was the positive control. Adult feeding used 25 mg/ml fiber in 5% sucrose-water. Larval feeding used 0.25 g fiber per bottle, and 1.0 g per bottle for RCF-2 and RCF-4.
• Main results:
  • After adult feeding, all tested fibers produced statistically significant increases in exceptional (aneuploid-derived) offspring compared with controls. Rates were generally 2 to 3 times the control rate: control 3 of 15,690 (0.02%); RCF-1 19 of 36,424 (0.052%); RCF-2 29 of 38,408 (0.076%); RCF-3 20 of 32,295 (0.062%); RCF-4 24 of 42,830 (0.056%); chrysotile 14 of 20,820 (0.070%).
  • After adult feeding, RCF-1 and chrysotile increased chromosome gain. The other fibers increased chromosome loss only.
  • The author described the effects of adult feeding as modest but statistically significant.
  • After larval feeding at 0.25 g per bottle, RCF-1 and RCF-3 significantly increased both chromosome gain and loss. Exceptional offspring were 18 of 18,180 (0.099%) for RCF-1 and 21 of 26,510 (0.079%) for RCF-3, against 9 of 59,512 (0.015%) for controls.
  • After larval feeding, RCF-2 and RCF-4 showed no significant effect, either at 0.25 g or at the higher dose of 1 g per bottle.
• The authors' conclusion: The author concluded that, at least for fruit-fly female germ cells, RCFs may pose a threat as inducers of aneuploidy. The author added that, to the extent fly results can be extrapolated to higher organisms, some concern may be appropriate for workers exposed to high levels of mineral fibers.
• Limitations the authors state:
  • Actual fiber consumption was not measured. Larvae may have received a lower dose than adults.
  • The fibers formed thick slurries that were hard to dispense evenly onto the feeding surfaces.
  • Results for each treated group come from a single experiment at one dose.
  • The author was reluctant to draw conclusions about apparent differences between broods and said further experiments would be needed.
  • Any concern for workers exposed to high levels of mineral fibers depends on how far fruit-fly results can be extrapolated to higher organisms.

Topics

Medical terms in this study, explained in our Lexicon: Mineral Fiber, Insulator.

Related studies

• Chrysotile and amosite asbestos induce germ-line aneuploidy in Drosophila — C. Osgood, D. Sterling (1991)
• On the mechanism of the electrophysiological changes and membrane lesions induced by asbestos fiber exposure in Xenopus laevis oocytes — A. Bernareggi, G. Conte, et al. (2019)
• Effect of Synthetic Vitreous Fiber Exposure on TMEM16A Channels in a Xenopus laevis Oocyte Model — M. Zangari, G. Zabucchi, et al. (2024)
• Refractory ceramic fiber exposure and pleural plaques — J. Lockey, G. Lemasters, et al. (1996)
• Mechanism of refractory ceramic fiber- and rock wool-induced cytotoxicity in alveolar macrophages — K.A. Kim, W.K. Lee, et al. (2001)
• Refractory ceramic fibers activate alveolar macrophage eicosanoid and cytokine release — G.D. Leikauf, S.P. Fink, et al. (1995)

Browse more research in Mutation Research, or return to medical research.