Y. Morimoto et al., SYNERGISTIC EFFECTS OF MINERAL FIBERS AND CIGARETTE-SMOKE ON THE PRODUCTION OF TUMOR-NECROSIS-FACTOR BY ALVEOLAR MACROPHAGES OF RATS, British Journal of Industrial Medicine, 50(10), 1993, pp. 955-960
The objective of this study was to evaluate the combined effects of mi
neral fibres and cigarette smoke on the production of tumour necrosis
factor (TNF) by alveolar macrophages. Rats were exposed to cigarette s
moke in vivo, and production of TNF by alveolar macrophages was measur
ed in the presence of mineral fibres in vitro. For smoke exposure, rat
s were divided into two groups. Five were exposed to a daily concentra
tion of 10 mg/m3 of cigarette smoke for an eight hour period, and five
rats (controls) were not exposed to smoke. Bronchoalveolar lavage was
performed after exposure to smoke and the recovered alveolar macropha
ges were incubated with either chrysotile or ceramic fibres on a micro
plate for 24 hours. Activity of TNF in the supernatant was determined
by the L-929 fibroblast cell bioassay. When alveolar macrophages were
not stimulated by mineral fibres, production of TNF by rats exposed to
smoke and unexposed rats was essentially the same. When alveolar macr
ophages were stimulated in vitro by chrysotile or ceramic fibres, prod
uction of TNF by alveolar macrophages from rats exposed to smoke was h
igher than that by alveolar macrophages from unexposed rats. The findi
ngs suggest that cigarette smoke and mineral fibres have a synergistic
effect on TNF production by alveolar macrophages.