Mucous Cell Metaplasia in the Airways of Rats Exposed to Machining Fluids

Authors: Gordon T.¹; Harkema J.R.²

Source: Fundamental and Applied Toxicology, Volume 28, Number 2, December 1995 , pp. 274-282(9)

Publisher: Academic Press

Abstract:

Occupational exposure to microbial-contaminated machining fluids is associated with a variety of adverse pulmonary effects including chronic bronchitis and increased sputum production. We have previously demonstrated in F344 rats that inhaled endotoxin can increase the amount of stored intraepithelial mucosubstances (Vs) in the respiratory tract. The purpose of the present study was to examine the effect of endotoxin-contaminated machining fluid aerosols on mucous production. Rats were exposed to aerosols of pyrogen-free water, 1 or 10 mg/m 3 used machining fluid, or 10 mg/m 3 unused machining fluid for 3 hr/day for 3 days. Twenty-four hours after the final exposure, right lung lobes were lavaged and the nasal cavity and left lung were fixed in formalin. The amount of Alcian blue/periodic acid-Schiff-stained mucosubstances was determined by morphometry. Exposure to 10 mg/m 3 used machining fluid (equivalent to 0.8 mug/m 3 endotoxin) produced a significant increase in Vs in the epithelial lining of both the nasal septum and intrapulmonary airways. These changes in Vs were accompanied by a significant increase in total cells and neutrophils in the lavage fluid. No changes in stored mucosubstances or lavage parameters were found in animals exposed to 1 mg/m 3 used machining fluid aerosols. A significant increase in Vs was observed in the nasal septum but not in the intrapulmonary airways of animals exposed to 10 mg/m 3 unused machining fluids (no measurable endotoxin). These results suggest that in addition to endotoxin, nonendotoxin components of machining fluids may contribute to the increase in sputum and chronic bronchitis reported for workers exposed to machining fluid aerosols.

Language: English

Document Type: Research article

Affiliations: 1: Institute of Environmental Medicine, New York University Medical Center, Long Meadow Road, Tuxedo, New York, 10987 2: Department of Pathology, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, 48823

Publication date: 1995-12-01

• In this: publication
• By this: publisher
• In this Subject: Ecology ,  Toxicology
• By this author: Gordon T. ;  Harkema J.R.

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