Biopersistance and bronchoalveolar lavage investigations in rats after a subacute inhalation of various man-made mineral fibres

In an integrated project three different administration modes were compared in the rat: inhalation, intratracheal instillation and intraperitoneal injection. Further variables are the fibre type, the exposure time and the exposure dose. The final goal is to establish a standardized method to test fibrous particulates in animal experiments. Only the inhalation study is reported in this paper. Biopersistence of fibres is dependent on three main items: dissolution, mechanical disintegration and dislocation of fibres. Contribution of these processes for removal of fibres out of rat lungs was analysed by determination of the number of retained fibres and their length and diameter. Additionally, the macrophage-mediated clearance capacity was measured using tracer particles (46Sc2O3). the inflammatory potency of fibres was characterised by analysis of the bronchoalveolar lavage (BAL). Parts of the study are not totally completed. For fibre counts intermediate results are given.