Archives of toxicology
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Archives of toxicology · Jun 2005
Respiratory effect of acute and subacute exposure to endotoxin-contaminated metal working fluid (MWF) aerosols on Sprague-Dawley rats.
Male Sprague-Dawley rats were exposed to a water-soluble metal working fluid (MWF) (5% v/v) contaminated with endotoxins (10,000 eu/ml or 100,000 eu/ml) at 10 mg/m3 for six hours per day for three days (acute exposure) or two weeks (subacute exposure). The geometric mean diameter of the MWF aerosols was 1.56 microm, and the airborne endotoxin concentrations ranged from 1,231 to 2,173 eu/m3 (10,000 eu/ml in the bulk MWF) for the low dose and 19,263-27,386 eu/m3 (100,000 eu/ml in the bulk MWF) for the high dose. Minimal effects were observed after exposure to 10 mg/m3 of the MWF without endotoxins for three days or two weeks. ⋯ The level of endotoxin-specific IgE in the serum obtained from the rats exposed to the MWF with endotoxins increased dose-dependently, while the levels of total immunoglobulins (IgG(1), IgG(2a) and IgE) and endotoxin-specific IgG(1) and IgG(2a) remained unchanged. Accordingly, the current results indicate that lung inflammation can be immediately induced by acute or subacute exposure to an MWF contaminated with endotoxins, and macrophages would appear to play a role in the induction of inflammation along with B-cell functions rather than T-cell functions, after subacute exposure to an MWF with endotoxins. In addition, endotoxin-specific IgE is an early marker for endotoxin exposure in the workplace.