Intrapleural injection of asbestos induces early sister chromatid exchanges increase in bone marrow cells (Abstract)
Inflammatory processes have been suggested to induce genetic modifications. Measurement of sister chromatid exchanges (SCE) provides a very sensitive and quantitative assay, correlated with mutagenic action of most chemical or physical agents. A measure of SCE of bone marrow cells has been developed in rats. In controls from 3 months to 2 years old SCE is constant, 2.37/cell a = 0.22. The kinetic response of SCE after intrapleural injection of 20 mg crocidolite has been studied. Increase of SCE is observed from 3–5 days after the inj ection with a maximum value of 3.68 a = 0.11. Only carcinogenic and not mutagenic effects of asbestos have been established in vivo. Moreover this compound does not induce any increase of SCE in vitro. During the first few days, translocation of fibres to bone marrow is negligible. Thus bone marrow is not a target organ. From its transient aspect, SCE increase seems correlated with inflammatory reaction induced by intrapleural injection. This assumption is being substantiated. Preliminary results demonstrate a serum factor from treated animals that induces SCE increase in controls.