OBJECTIVETo investigate the cell proliferation and genome stability in workers with occupational exposure to diesel exhaust (DE).

METHODSIn 2012, 117 DE-exposed workers and 106 control workers were recruited by cluster sampling in this study. The demographic data were obtained by questionnaire survey. The airborne fine particle and enriched polycyclic aromatic hydrocarbons (PAHs) at different workplaces were collected and analyzed. The concentrations of main PAHs monohydroxy metabolites in the urine were determined by high performance liquid chromatography-mass spectrometry (LC-MS), which could reflect the internal exposure level of DE. The cell proliferation capacity and genome stability in the periphery lymphocytes of workers were evaluated by cytokinesis-block micronucleus (CBMN) cytome assay.

RESULTSThe concentrations (median (P5-P95)) of total PAHs monohydroxy metabolites in the urine of exposed group and control group were 12.96 (4.73-28.10), 4.76 (0.90-15.00) µg/L, respectively, and the exposed group was higher than that of controls (Z = -8.77, P < 0.001). The nuclear division index (NDI) of exposed group and control group was 1.68±0.13, 1.85±0.16, respectively, and the NDI of exposed group showed significantly decreased (t = 8.86, P < 0.001), while the genome instability index calculated by micronucleus, nuclear bridges and nuclear buds, of exposed group and control group was 13.27±6.26, 4.83±3.38, respectively, and the exposed group had statistically significant increase (Z = -10.08, P < 0.001). The tertiles of total PAHs monohydroxy metabolites in the urine were categorized into low, medium and high groups (<5.96, 5.96-12.46, >12.46 µg/L). With the NDI decreased, 1.81±0.17, 1.79±0.17, 1.68±0.14 (F = 13.14, P < 0.001), genome instability index began to increase 5.80±4.15, 9.97±7.14, 11.99±6.61 (/1 000), respectively (χ(2) = 36.74, P < 0.001). With the increase of total PAHs monohydroxy metabolites level in corresponding groups. In addition, the NDI was negatively correlated with the frequencies of micronucleus, nuclear bridges, nuclear buds and genome instability index, respectively, and the difference was statistically significant (P < 0.001).

CONCLUSIONSDE exposure lead to inhibition of cell proliferation capacity and increase genome instability in the peripheral lymphocytes of occupational-exposed population, providing important clues and evidence for early biomarkers monitoring.