A study of guanidinobenzoatase during development of mesothelioma induced in the rat by fibrous erionite

Our plain-English summary of A study of guanidinobenzoatase during development of mesothelioma induced in the rat by fibrous erionite, by F.S. Steven, R.J. Hill (British Journal of Cancer, 1988).

The study

• Authors: F.S. Steven, R.J. Hill
• Journal: British Journal of Cancer
• Published: 1988;58(5):610-3
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Exposure to the fibrous mineral erionite is known to induce mesothelioma in man and laboratory animals. Previous studies demonstrated the presence of a trypsin-like protease associated with tumour cells. This protease could be demonstrated by the use of fluorescent probes which located cells possessing this enzyme. We have employed this fluorescent probe technique to follow the early events in the lungs of rats exposed to erionite. The evidence presented shows that the mesothelial cells initially lack this enzyme but the enzyme can be detected within hours of exposure of the rat to erionite. The number of mesothelial cells possessing the enzyme steadily increased after a single exposure to the mineral until the animal finally died with a massive pleural tumour. This is the first study of such fluorescent probes in the early stages of tumour induction.

In plain English

This was a laboratory experiment in rats using fibrous erionite, a mineral fibre that is not asbestos. Twelve male rats were split into six groups. One group had salt solution injected into the chest cavity, and five groups had 20 mg of fibrous erionite injected there. Two more rats received erionite milled into shorter particles. Animals were killed between 1 hour and 7 days later. Lung sections were stained with a fluorescent dye that marks cells carrying an enzyme called guanidinobenzoatase (GB). Tissue from an earlier study, including seven rats that had developed mesothelioma, was also stained. The cells lining the lung surface (mesothelial cells) showed no GB in saline-injected rats. After fibrous erionite, these cells lacked GB at 1 hour, some had it at 24 hours, most at 48 hours, and nearly all at 72 hours. By 7 days the pleura was markedly thickened. Virtually every mesothelioma cell stained strongly. Short erionite produced little GB and no pleural thickening. The authors concluded that particle size and shape relate to GB expression as they do to mesothelioma formation.

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: intrapleural injection in rats followed by fluorescent staining of lung tissue sections at set times
• Who was studied: Twelve male LAC:P rats of about 150 g body weight, randomly allocated to 6 groups. Two further rats received short erionite. Stored tissue from a previous study of similarly inoculated rats was also examined, including seven animals that had developed mesothelioma.
• Exposure: Fibrous erionite from Oregon, USA, milled at the MRC Pneumoconiosis Unit. Groups 2 to 6 received 20 mg in 0.4 ml by intrapleural injection; group 1 received 0.4 ml saline only. A short form of the same erionite, made by further milling, was injected into 2 rats. Animals were killed at 1 h, 24 h, 48 h, 72 h and 7 days (short erionite: 1 and 7 days).
• Main results:
  • In the saline-injected control rats, mesothelial cells showed no cytoplasmic or cell-surface staining for GB.
  • At 1 hour after fibrous erionite, mesothelial cells were enlarged and 'humped' but lacked GB.
  • At 24 hours after fibrous erionite, some mesothelial cells showed GB staining.
  • At 48 hours, most mesothelial cells showed GB staining.
  • At 72 hours, mesothelial cells had increased in number and nearly all showed GB staining.
  • At 7 days the pleura was considerably thickened. Animals examined between 7 and 140 days showed a similar pattern of pleural reaction and GB expression.
  • In the mesothelioma sections, virtually every tumour cell showed strong staining. There was no detectable difference in pattern or intensity between tumour types.
  • Rats injected with short erionite showed little GB expression. At 7 days they had no pleural thickening, hyperplasia or cell infiltrates, and only an occasional stained mesothelial cell.
  • An extract of rat lung tissue blocked dye binding to most lung cells, but not to the mesothelial cells on the lung surface.
• The authors' conclusion: The authors concluded that changes in the mesothelium occurred very rapidly after fibrous erionite exposure. They also concluded that the model shows a correlation between the size and shape of mineral particles and GB expression, similar to the correlation with mesothelioma formation.
• Limitations the authors state:
  • The authors stated that the sections could not show whether the dye bound to enzyme inside the cell or on the cell membrane.
  • The authors stated that aggregates of GB-positive cells in the alveoli beneath the pleura were not studied and await further study.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, erionite, Mesothelial Cells.

Related studies

• Pluripotential nature of mesotheliomata induced by inhalation of erionite in rats — N.F. Johnson, R.E. Edwards, et al. (1984)
• The in vitro genetic effects of fibrous erionite and crocidolite asbestos — K.T. Kelsey, E. Yano, et al. (1986)
• In vitro genotoxic activities of fibrous erionite — A. Poole, R.C. Brown, et al. (1983)
• CT findings in malignant pleural mesothelioma related to nonoccupational exposure to asbestos and fibrous zeolite (erionite) — C. Erzen, M. Eryilmaz, et al. (1991)
• Erionite exposure and mesotheliomas in rats — J.C. Wagner, J.W. Skidmore, et al. (1985)
• Mesotheliomas induced in rats by the fibrous mineral erionite are independent from p53 alterations — E.V. Kleymenova, G. Horesovsky, et al. (1999)

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