Reactive Oxygen Species Measured from Suspensions of Polymorphonuclear Leukocytes after the Addition of Silicon Carbide Particles

A sample of silicon carbide (SiC) dust was collected from a factory manufacturing SiC abrasives, then tested in vitro to find out whether it could produce reactive oxygen species (ROS) after its addition to human polymorphonuclear leukocyte suspensions. We compared the results of milled and unmilled SiC with those obtained from quartz dust and asbestos fibres, which are known causes of severe pulmonary lesions. ROS production was measured with the chemiluminescence (CD technique. CL values obtained with our two forms of SiC (milled and unmilled) were approximately twice those measured in the controls (where no mineral particles were added), approximately 80% of the values found with asbestos fibres, and only 12.5% of the values measured with quartz. Iron traces were found on the surface of a small number of the particles tested, which could be as a result of contamination. These iron traces could help to explain our findings, since, together with the iron traces present in the culture medium, they could have triggered ROS generation in a Fenton-type reaction.