Results of current intraperitoneal carcinogenicity studies with mineral and vitreous fibres

Our plain-English summary of Results of current intraperitoneal carcinogenicity studies with mineral and vitreous fibres, by M. Roller, F. Pott, K. Kamino, et al (Experimental and Toxicologic Pathology, 1996).

The study

• Authors: M. Roller, F. Pott, K. Kamino, G.H. Althoff, B. Bellmann
• Journal: Experimental and Toxicologic Pathology
• Published: 1996;48(1):3-12
• Cited by: 40 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The study includes some 50 groups of male or female Wistar rats tested in three series. Except for one untreated group and 3 vehicle control groups, the animals were injected intraperitoneally (i.p.) once or repeatedly with dust suspensions and then examined, after lifetime observation up to 30 months, for tumours in the abdominal cavity. 1 granular dust (silicon carbide), 2 asbestos dusts (crocidolite, tremolite) and 11 vitreous fibre dust samples were administered. 5 of the vitreous fibre types were fine fibre fractions from 4 commercial insulation wools and 1 experimental wool, the others were prepared by milling glass microfibres, which have, per se, a small diameter range. The dosage per rat differed over a wide range in accordance with experience from earlier studies. The lowest dose was 0.04 x 10(9) crocidolite fibres in 0.5 mg dust, and the highest amounted to 20 x 10(9) glass fibres in 1000 mg divided into 40 weekly injections. Two mesotheliomas were found in a total of 395 rats treated with saline or granular silicon carbide (250 or 1000 mg). Eleven fibre dusts produced dose-dependent mesotheliomas at rates of up to 97 %, but the calculated fibre number > 5 micrometers in length required for inducing a 25 % tumour risk differed between the fibre samples tested in the relation of 1 to about 1000. UICC-like crocidolite heads the ranking order; the glass fibre B-01, which possesses a low durability in the body, ends it together with a rather thin sample of glass fibre type B-09. The stone fibre MMVF-21 takes a high place in the ranking order, similar to the tremolite sample. The results correspond to those of earlier i.p. tests.

In plain English

This interim report of an animal experiment covered some 50 groups of male or female Wistar rats in three series. Most rats were injected into the abdominal cavity once or repeatedly and observed up to 30 months for abdominal tumours. The dusts were granular silicon carbide, two asbestos dusts (crocidolite, tremolite) and 11 vitreous fibre samples, including fine fractions of glass, stone and slag insulation wools. Two mesotheliomas were found among 395 rats given saline or granular silicon carbide. Eleven fibre dusts produced dose-dependent mesotheliomas at rates of up to 97 %. The calculated number of fibres longer than 5 micrometres needed for a 25 % tumour risk differed between samples by about 1 to 1000. Crocidolite headed this ranking; the stone fibre MMVF-21 ranked high, similar to tremolite. The glass fibre B-01, which has low durability in the body, ended it together with a rather thin B-09 glass fibre sample. The authors concluded that fibrous mineral and vitreous particles are a specific carcinogenic agent if sufficiently long, thin and durable. Histological examination was incomplete for some groups.

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 (intraperitoneal injection carcinogenicity study in rats); interim report presented as a poster
• Who was studied: Some 50 groups of male or female Wistar rats in three series (A, B, C), observed for up to 30 months; groups ranged from 24 to 96 rats; findings as of March 1995; institutes in Düsseldorf and Hannover, Germany
• Exposure: Intraperitoneal injections of granular silicon carbide, crocidolite, tremolite and 11 vitreous fibre samples. Five vitreous samples were fine fractions of 4 commercial insulation wools and 1 experimental wool; the others were milled glass microfibres. Controls received saline or no treatment. Doses ranged widely, up to 1000 mg of glass fibre given in 40 weekly injections.
• Main results:
  • Two mesotheliomas were found in a total of 395 rats treated with saline or granular silicon carbide (250 or 1000 mg).
  • Eleven fibre dusts produced dose-dependent mesotheliomas at rates of up to 97 %.
  • The calculated number of fibres longer than 5 micrometres required to induce a 25 % tumour risk differed between the fibre samples in the relation of 1 to about 1000.
  • Crocidolite headed the ranking. The glass fibre B-01, which has low durability in the body, ended it together with a rather thin sample of glass fibre type B-09.
  • The stone fibre MMVF-21 took a high place in the ranking order, similar to the tremolite sample.
  • Compared with saline controls, the reduction in weight gain was less than 10 %, even in groups given up to 1000 mg of dust or with mesothelioma frequencies above 50 %.
• The authors' conclusion: The authors concluded that there were no significant signs of toxicity that would support tumour induction being a non-specific effect. They concluded that fibrous mineral and vitreous particles are a specific carcinogenic agent if they are sufficiently long, thin and durable.
• Limitations the authors state:
  • Histopathological diagnoses were not yet completed for all groups, so some 25 % tumour-dose values may change after final evaluation.
  • The 'positive' rat counts include rats only macroscopically suspected of having mesothelioma.
  • This is an interim report, and the authors discussed the results only very briefly.

Topics

Medical terms in this study, explained in our Lexicon: Vitreous, Crocidolite, Tremolite, Mesothelioma, UICC.

Related studies

• Detection of mineral fibre carcinogenicity with the intraperitoneal test--recent results and their validity — F. Pott (1995)
• Dose-response relationship of fibrous dusts in intraperitoneal studies — M. Roller, F. Pott, et al. (1997)
• Induction of 8-hydroxydeoxyguanosine by man made vitreous fibres and crocidolite asbestos administered intraperitoneally in rats — C. Schürkes, W. Brock, et al. (2004)
• Bromo-deoxyuridine (BRDU) uptake in the lungs of rats inhaling amosite asbestos or vitreous fibres at equal airborne fibre concentrations — K. Donaldson, D.M. Brown, et al. (1995)
• Absence of carcinogenic response to multiwall carbon nanotubes in a 2-year bioassay in the peritoneal cavity of the rat — J. Muller, M. Delos, et al. (2009)
• Respiratory health effects of man-made vitreous (mineral) fibres — P. De Vuyst, P. Dumortier, et al. (1995)

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