Kerosene soot genotoxicity: enhanced effect upon co-exposure with chrysotile asbestos in Syrian hamster embryo fibroblasts

Epidemiological and experimental studies have suggested an enhancement of a sbestos-induced bronchogenic carcinoma by cigarette smoke. Further, our rec ent experimental and epidemiological studies have indicated that besides sm oking, several other compounds including kerosene soot may accelerate disea se processes in asbestos-exposed animals as well as in the humans. Incomple te combustion of kerosene oil generates large volumes of soot, which contai ns various polycyclic aromatic hydrocarbons and aliphatic compounds. As rep orted earlier, exposure to kerosene soot is known to cause biochemical and pathological changes in the pulmonary tissue, which may cause cardiopulmona ry disorders. In this study we investigated genotoxic effects caused by ker osene soot and chrysotile asbestos as well as co-exposure of kerosene soot and chrysotile using Syrian hamster embryo fibroblasts (SHE). The micronucl eus assay revealed a significant increase of induced micronuclei (MN), (P l ess than or equal to 0.05) in SHE cells after treatment with kerosene soot (0.5-1.0 mu g/cm(2)) for 66 h (36 MN/1000 cells). Combined treatment with c hrysotile and soot induced up to 110 MN/1000 cells (chrysotile alone: 80 MN /1000 cells; concentrations: 1 mu g/cm(2), exposure times: 66 h). Kinetocho re staining revealed mainly clastogenic effects in all cases (soot: 21.3% C RMN+; chrysotile: 27%; soot + chrysotile: 27.6%; control: 20.8%). This is t he first study showing that kerosene soot is not only genotoxic but it can also elevate the genotoxic potential of chrysotile asbestos. This informati on may be of importance for workers occupationally exposed to asbestos and domestically exposed to kerosene soot. (C) 2000 Elsevier Science Ireland Lt d. All rights reserved.