Pulmonary and pleural leukocytes from F344 rats produce elevated levels of fibronectin following inhalation of refractory ceramic fibers

Our plain-English summary of Pulmonary and pleural leukocytes from F344 rats produce elevated levels of fibronectin following inhalation of refractory ceramic fibers, by T.R. Gelzleichter, J.B. Mangum, E. Bermudez, et al (Experimental and Toxicologic Pathology, 1996).

The study

• Authors: T.R. Gelzleichter, J.B. Mangum, E. Bermudez, B.A. Wong, O.R. Moss, J.I. Everitt
• Journal: Experimental and Toxicologic Pathology
• Published: 1996;48(6):487-9
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This was an experiment in male Fischer (F344) rats on fibronectin, a protein the authors describe as thought to play an early role in scarring (fibrosis) of the lung and the pleura, the lining around the lungs. Rats breathed filtered air or 89 mg/m3 of RCF-1, a kaolin-based refractory ceramic fiber, for 6 hours a day for 5 days. They were examined 1 day and 4 weeks later. Fibronectin was significantly higher in fluid washed from the lungs and from the pleural space of exposed rats at both times. Cultured lung white blood cells from exposed rats made 74% and 161% more fibronectin (days 6 and 33). Pleural white blood cells made 31% more at day 6, with no increase at day 33. Adding RCF-1 directly to cells in the dish did not significantly change fibronectin. Crocidolite asbestos, used as a comparison fiber, significantly lowered fibronectin from lung cells but not pleural cells. The authors concluded that inhaled RCF-1 raises fibronectin in the pleural space and that pleural white blood cells may contribute.

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: rats were exposed to fibers by inhalation, and lung and pleural white blood cells were also exposed to fibers in cell culture (in vitro)
• Who was studied: Male Fischer (CDF (F344)/CrlBR) rats from Charles River Breeding Laboratories, Raleigh, NC; the number of rats is not stated. Pulmonary (lung) and pleural white blood cells (leukocytes) were collected by lavage.
• Exposure: RCF-1, a kaolin-based refractory ceramic fiber, inhaled at 89 mg/m3 for 6 hours a day for 5 days. The aerosol contained 6206 total fibers per cm3, of which 2645 were WHO respirable fibers. Controls breathed filtered air. In vitro, cells were treated with 2.5 or 5 micrograms per cm2 of RCF-1, or of NIEHS crocidolite asbestos as a reference fiber.
• Main results:
  • In rats that inhaled RCF-1, soluble fibronectin was significantly elevated in both lung (bronchoalveolar) and pleural lavage fluid after the 5-day exposure, and it remained elevated at day 33.
  • Cultured lung lavage white blood cells from fiber-exposed rats produced 74% more soluble fibronectin at day 6 and 161% more at day 33 than cells from air-exposed rats.
  • Cultured pleural white blood cells from fiber-exposed rats produced 31% more soluble fibronectin at day 6.
  • Pleural white blood cells showed no increase in fibronectin production at day 33.
  • Adding RCF-1 directly to cultured lung or pleural white blood cells did not significantly change fibronectin in the culture medium.
  • Crocidolite asbestos at 2.5 and 5 micrograms per cm2 significantly decreased fibronectin from cultured lung white blood cells (0.037 and 0.048 micrograms per ml, compared with 0.075 untreated), but not from pleural white blood cells.
  • In air-exposed (control) rats, total fibronectin yield was roughly 20-fold higher in pleural lavage fluid than in lung lavage fluid. Medium from pleural white blood cells contained 9-fold more fibronectin than medium from lung white blood cells.
• The authors' conclusion: The authors concluded that inhaling RCF-1 results in elevated fibronectin in the pleural space and that pleural white blood cells may contribute to this. They added that the response was weaker and shorter than in lung (alveolar) white blood cells, and that direct contact with RCF-1 in vitro was not enough to cause it.

Topics

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

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