In vitro correlates of mineral dust toxicity

In vitro studies of mineral fibres have shown that these materials are capable of causing the production of free radical damage (measured by the accumulation of thiobarbituric acid-reactive material) in a way that does not depend on fibre morphology but rather on a surface property, probably the presence of iron. The DNA-damaging activities of the same dusts were measured in an assay based on the production of single-stranded DNA. Activity in this assay was again not dependent on the presence of fibres. In contrast the cytotoxicity of mineral fibres towards V79-4 cells correlated better with in vivo tumorigenicity than did either of the above activities. The activity of fibres against a macrophage-like cell demonstrated that both fibre morphology and chemical properties are important determinants of biological activity.