Predominant induction of kinetochore‐containing micronuclei by extracts of diesel exhaust particulates in cultured human lymphocytes

The aneuploidy‐inducing activity of extracts of diesel exhaust particulates from light duty (LD) and heavy duty (HD) engines was investigated in cultured peripheral blood lymphocytes of 8 healthy donors using the cytokinesis‐block micronucleus test with the kinetochore labelling modification. A majority of the subjects tested showed a significant kinetochore‐positive micronucleus induction after treatment with the highest dose (150 μg/ml) of LD extract, although some subjects also showed induction of kinetochore‐negative micronuclei. Only one subject had significantly increased numbers of kinetochore‐positive micronuclei at a dose of 400 μg/ml of HD extract. These results suggest that diesel extract, at least LD extract, possesses the ability to induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks. © 1994 Wiley‐Liss, Inc.