Evaluating the genotoxic effects of workers exposed to lead using micronucleus assay, comet assay and TCR gene mutation test

To evaluate the genotoxic effects of lead (Pb) exposure, 25 workers in a workplace producing storage battery were monitored for three genetic end-points using micronucleus (MN) assay, comet assay and TCR gene mutation test. Twenty-five controls were matched with workers according to age, gender and smoking. The air Pb concentration in the workplace was 1.26 mg/m3. All subjects were measured for Pb concentration of blood by atom absorption spectrophotometry. The mean Pb concentration of blood in workers (0.32 mg/l) was significantly higher than that in controls (0.02 mg/l). The results of MN test showed that the mean micronuclei rate (MNR) and mean micronucleated cells rate (MCR) in workers were 9.04 ± 1.51‰ and 7.76 ± 1.23‰, respectively, which were significantly higher than those (2.36 ± 0.42‰ and 1.92 ± 0.31‰) in controls (P < 0.01). It was found in the comet assay that the mean tail length (MTL) of 25 workers and 25 controls were 2.42 ± 0.09 and 1.02 ± 0.08 μm, respectively, there was significant difference between workers and controls for MTL (P < 0.01), also the difference of the mean tail moment (MTM) between workers (0.85 ± 0.05) and controls (0.30 ± 0.09) was very significant (P < 0.01). However, in TCR gene mutation assay Mfs-TCR of workers and controls were 1.69 ± 0.15 × 10−4 and 1.74 ± 0.17 × 10−4, respectively, there was no significant difference between workers and controls (P > 0.05). The results of our study indicated that the genetic damage was detectable in 25 workers occupationally exposed to lead.