Comparative in vitro cytotoxicity and relative pathogenicity of mineral dusts.
Vallyathan-V; Schwegler-D; Reasor-M; Stettler-L; Clere-J; Green-FH
Ann Occup Hyg, Inhaled Particles VI 1988 Dec; 32(Suppl 1):279-289
The in-vitro cellular and in-vivo pathological reactions to various well characterized minerals were examined. Histopathological changes arising in Fischer-344-rats intratracheally instilled with aliquots of various mineral dusts were studied. The dusts used included barite (13462867), bentonite (1302789), coal, feldspar, kaolin (1332587), silica (14808607), talc (14807966), and vermiculite (1318009). Indicators of cytotoxicity were taken to be the release of alveolar macrophage enzyme and sheep red cell hemolysis. Reactions induced by instillation of 5 milligrams of bentonite, silica and kaolin were examined at 1, 7, 90, and 180 days. While all three produced an acute inflammatory cellular response in-vivo, only silica induced a progressive granulomatous and fibrotic response. Bentonite and kaolin were more hemolytic than silica. Kaolin induced greater release of macrophage cytosolic and lysosomal enzymes than silica and bentonite inhibited the activity of alveolar macrophage enzymes. The pulmonary response to bentonite and kaolin was temporary, resolving completely by 6 months after exposure. The authors conclude that in-vivo animal studies are the best indicators of pulmonary fibrogenic potential in humans, and that the two in-vitro assays used in this study did not reflect the fibrogenic potential of the mineral dusts.
NIOSH-Author; Dust-exposure; Laboratory-animals; Airborne-dusts; Cytotoxicity; Alveolar-cells; Lung-cells; Mineral-dusts; In-vitro-studies; Pulmonary-system-disorders
13462-86-7; 1302-78-9; 1332-58-7; 14808-60-7; 14807-96-6; 1318-00-9
Dodgson-J; McCallum-RI; Bailey-MR; Fisher-DR
Annals of Occupational Hygiene, Inhaled Particles VI