Tumorigenesis by a ferroactinolite mineral

Our plain-English summary of Tumorigenesis by a ferroactinolite mineral, by D.L. Coffin, L.D. Palekar, P.M. Cook (Toxicology Letters, 1982).

The study

• Authors: D.L. Coffin, L.D. Palekar, P.M. Cook
• Journal: Toxicology Letters
• Published: 1982;13(3-4):143-9
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In lifetime exposure of male Fischer-344 rats to ferroactinolite fibers and to UICC amosite asbestos fibers by means of intratracheal and intrapleural treatments, oncogenesis was greater in the lung for the ferroactinolite and in the pleura for the amosite. The lack of correlation between the effects of the two methods of exposure suggests that in this instance intrapleural inoculation was not a good predictor of pulmonary response on the basis of mass dose. Another feature of the ferroactinolite was that pleural tumors resulted from intratracheal instillations. Conversely, lung tumors or tumorlike lesions were also induced by intrapleural inoculations of ferroactinolite. These facts suggest a greater in vivo transport for the ferroactinolite than for the amosite. Since there are far fewer mineral fibers per mass unit in the ferroactinolite the tumor yield per unit of mineral fibers was strikingly greater by both routes of administration for ferroactinolite than for amosite.

In plain English

In this experiment, male Fischer-344 rats received ferroactinolite fibers from iron-formation rocks or standard UICC amosite asbestos fibers. One set had twelve weekly doses put into the windpipe (0.5 mg ferroactinolite or 0.25 mg amosite each time). Some of these were killed within a year for early-pathology and fiber studies, and others were followed for life. Another set had one 20 mg injection into the chest cavity and was followed for life. After windpipe dosing, lung tumors occurred in 3.9% of ferroactinolite rats, 0.71% of amosite rats, 0.6% of sham controls and 1.4% of untreated controls. Mesothelioma was uncommon in both treated groups and was not statistically significant. After chest-cavity injection, mesothelioma occurred in 33.6% of amosite rats and 23% of ferroactinolite rats. The two minerals did not differ significantly, but both differed from controls (P less than 0.0001). Fibers of both types split lengthwise in the lung over time. The authors concluded that the intrapleural route was not a good predictor of lung tumors in this experiment. Two mesothelial tumors occurred in sham controls, and the authors suggested the gelatin vehicle as a possible cause.

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 (lifetime study in rats, intratracheal instillation and intrapleural inoculation, with sham and untreated controls; some intratracheal rats were killed at intervals up to 1 year)
• Who was studied: Specific pathogen-free male Fischer-344 rats. Some intratracheal rats were killed at intervals up to 1 year for early-pathology and fiber studies, and the rest were kept for life. Group sizes are given in the tables, but the scanned tables are too scrambled to assign each number to a group reliably.
• Exposure: Ferroactinolite fibers prepared from loose surface iron-formation rocks, compared with standard UICC amosite asbestos fibers. Intratracheal: twelve weekly instillations of 0.5 mg ferroactinolite or 0.25 mg amosite. Intrapleural: a single injection of 20 mg of each mineral.
• Main results:
  • Intratracheal route: lung tumor incidence was 3.9% for ferroactinolite, 0.71% for amosite, 0.6% for sham controls and 1.4% for untreated controls
  • Intratracheal route: hyperplastic lesions were similar in the two treated groups, at 6.6% (ferroactinolite) and 7.9% (amosite)
  • Intratracheal route: atypical cell hyperplasia incidence was significant compared with controls (P<0.005)
  • Intratracheal route: there was a low incidence of mesothelioma in both treated groups, and the incidence of mesotheliomas and metastatic tumors was not statistically significant
  • Intrapleural route: mesothelioma incidence was 33.6% in amosite-treated rats and 23% in ferroactinolite-treated rats
  • Intrapleural route: granuloma occurred in 20% of ferroactinolite-treated and 30.7% of amosite-treated rats
  • Intrapleural route: mesothelioma and granuloma incidence did not differ significantly between the two treated groups, but was highly significant compared with controls (P<0.0001)
  • Electron microscopy of lungs from rats killed at intervals showed that both ferroactinolite and amosite fibers split lengthwise over time into more, thinner fibers
• The authors' conclusion: The authors concluded that, by mass dose, ferroactinolite was more potent at causing tumors by the intratracheal route and amosite by the intrapleural route (the intrapleural difference was not statistically significant). They concluded that, under the conditions of this experiment, the intrapleural route was not a good predictor of lung tumors.
• Limitations the authors state:
  • Two mesothelial tumors occurred in sham-treated controls, which the authors suggest may be due to the gelatin used as the vehicle

Topics

The National Library of Medicine indexes this study under subjects our site covers: Actinolite, Amosite.

Medical terms in this study, explained in our Lexicon: Tumorigenesis, Ferro-actinolite, UICC, Amosite, Oncogenesis, Pleura, Mineral Fiber.

Related studies

• Interpretation of the carcinogenicity of amosite asbestos and ferroactinolite on the basis of retained fiber dose and characteristics in vivo — P.M. Cook, L.D. Palekar, et al. (1982)
• Correlation of in vitro and in vivo methods by means of mass dose and fiber distribution for amosite and fibrous ferroactinolite — D.L. Coffin, L.D. Palekar, et al. (1983)
• Sumas Mountain chrysotile induces greater lung fibrosis in Fischer344 rats than Libby amphibole, El Dorado tremolite, and Ontario ferroactinolite — J.M. Cyphert, A. Nyska, et al. (2012)
• Rapporteur's Report Session 4: grunerite asbestos (amosite) and tremolite-ferroactinolite asbestos: risk of environmental mesothelioma — J.F. Gamble (2008)
• A comparison of asbestos fiber potency and elongate mineral particle (EMP) potency for mesothelioma in humans — D.H. Garabrant, S.T. Pastula (2018)
• Does qualitative examination of Elongated Mineral Particles (EMP) recovered from human and animal lungs provide reliable information on their carcinogenic and other effects? — B.W. Case (2018)

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