Effect of water-soluble metal working fluid aerosols on respiratory system after 13 weeks of repeated inhalation exposure in F344 rats.
Three groups of male F344 rats were exposed to a water-soluble metal working fluid (MWF) aerosol at concentrations of 20, 60 or 180 mg/m3 for 6 h/day, five days a week, for 13 weeks in inhalation chambers. The aerosol particles were normally distributed and the mass median aerodynamic diameter was 1.56 microm. Despite the absence of clinical findings or significant changes in body weight during the 13-week exposure period, the numbers of white blood cells and lung weights were significantly higher at the end of the 13-week exposure period. Exposure to 20 mg/m3 of the MWF aerosol was found to have an effect on the respiratory system, including an accumulation of foamy macrophages in the bronchoalveolar lavage (BAL) fluid and thickening of the alveolar walls in the histopathology. The level of histamine and number of polymorphonuclear (PMN) cells were also higher in the BAL fluid from the rats exposed to 60 mg/m3 of the MWF aerosol, while the respiratory inflammation was most pronounced in the rats exposed to 180 mg/m3 of the MWF aerosol, including the accumulation of PMNs and foamy macrophages in the BAL cells, lung weight increase and thickening of the alveolar walls. Immunoglobulin IgG2a level was also lower in the sera from the rats exposed to 180 mg/m3 of the MWF aerosol. Therefore, even though no clinical symptoms were observed in the rats exposed to the high MWF concentration, respiratory inflammation was still induced by a relatively low concentration of the MWF, while the immune system was affected by the high MWF concentration.
Lima
Cheol-Hong
CH
Center for Occupational Toxicology, Occupational Safety and Health Research Institute, Korea Occupational Saftty and Health Agency, Daejeon, South Korea.
Yu
Il Je
IJ
Kim
Hyeon-Young
HY
Lee
Seung-Bae
SB
Marshak
Daniel R
DR
Lee
Ji Hyun
JH
Kim
Kwang Jong
KJ
D000280:Administration, Inhalation; D000336:Aerosols; D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001273:Atmosphere Exposure Chambers; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D007136:Immunoglobulins / Q000097:blood / Q000187:drug effects; D007249:Inflammation / Q000139:chemically induced; D019570:Inhalation Exposure; D008168:Lung / Q000187:drug effects / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D012137:Respiratory System / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000276:immunology / Q000473:pathology; D012995:Solubility
D000336:Aerosols; D000393:Air Pollutants; D007136:Immunoglobulins