Production of reactive oxygen species by phagocytic cells after exposure to glass wool and stone wool fibres - effect of fibre preincubation in aqueous solution

The potential of four man-made vitreous fibres (MMVFs) (glass wool Code A, stone wool Code G, HT-N and MMVF 21) and of two natural mineral fibres (cro cidolite, erionite) to induce production of reactive oxygen species (ROS) b y differentiated HL-60 cells (HL-60-M cells) was investigated by determinat ion of luminol-enhanced chemiluminescence (CL). Quartz served as positive c ontrol. The same system was used to uncover possible influences of fibre pr eincubation in aqueous solutions on the ROS-generating potential. Following preincubation in unbuffered saline over about 4 weeks, Code A and G fibres showed decreased ROS-generating potential as compared to freshly suspended fibres. On the other hand, MMVF 21 and HT-N fibres as well as crocidolite and erionite showed no decreased CL after incubation in aqueous solutions. The observed decrease of the ROS-generating potential of Code A and G fibre s after preincubation may be an expression of fibre surface alterations (le aching, initiation of dissolution) that influences the response of exposed phagocytic cells. After incubation of both fibres in buffered solutions at different pH values (5.0, 7.3) a reduced ROS-generating potential was still discernible as compared to freshly suspended fibres. (C) 2000 Elsevier Sci ence Ireland Ltd. All rights reserved.