Assessing the suitability of 8OHdG and micronuclei as genotoxic biomarkers in chromateexposed workers: A crosssectional study

Abstract

Objectives We aimed to investigate suitable conditions of 8hydroxy2' deoxyguanosine (8OHdG) and micronucleus (MN) as genotoxic biomarkers at different levels of occupational chromate exposure. Design A crosssectional study was used. Participants 84 workers who were exposed to chromate for at least 1 year were chosen as the chromate exposed group, while 30 nonexposed individuals were used as controls. Main outcome measures Environmental and biological exposure to chromate was respectively assessed by measuring the concentration of chromate in the air (CrA) and blood (CrB) by inductively coupled plasma mass spectrometer (ICPMS) in all participants. MN indicators, including micronucleus cell count (MNCC), micronucleus count (MNC), nuclear bridge (NPB) and nuclear bud (NBUD) were calculated by the cytokinesisblock micronucleus test (CBMN), while the urinary 8OHdG was measured by the ELISA method and normalised by the concentration of Cre. Results Compared with the control group, the levels of CrA, CrB, MNCC, MNC and 8OHdG in the chromateexposed group were all significantly higher (p<0.05). There were positive correlations between log(8OHdG) and LnMNCC or LnMNC (r=0.377 and 0.362). The levels of LnMNCC, LnMNC and log (8OHdG) all have parabola correlations with the concentration of CrB. However, there was a significantly positive correlation between log (8OHdG) and CrB when the CrB level was below 10.50 μg/L (r=0.355), while a positive correlation was also found between LnMNCC or LnMNC and CrB when the CrB level was lower than 9.10 μg/L (r=0.365 and 0.269, respectively). Conclusions MN and 8OHdG can be used as genotoxic biomarkers in the chromateexposed group, but it is only when CrB levels are lower than 9.10 and 10.50 μg/L, respectively, that they can accurately reflect the degree of genetic damage.