Abstract:
[Objective] To investigate the effects of DDT and nano-TiO2 on ROS level and DNA damage in human embryo liver L-02 cells.
[Methods] L-02 cells were exposed separately to different doses of DDT(0.001, 0.01, 0.1 μmol/L), nano-TiO2 (0.01, 0.1, 1 μg/mL), and different concentration of DDT mixed with nano-TiO2 respectively for 24 h. Reactive oxygen species(ROS) level was determined by flow cytometry and DNA damage was measured by alkali and neutral comet assay.
[Results] It was observed that exposure to DDT greater than 0.01 μmol/L or 1 μg/mL nano-TiO2 alone could significantly increase ROS production compared with control cells(P<0.05). In alkaline comet assay, no significant effects on DNA damage were observed in single nano-TiO2 groups(P>0.05), but 0.01 μmol/L concentration of DDT or higher could induce DNA damage(P<0.05). However, there was no statistically significant increase of OTM in all groups compared with control group in neutral comet assay(P>0.05). Mixture of DDT and nano-TiO2 was synergistic to increase ROS generation and DNA single strand breaks(P<0.05).
[Conclusion] Combination of DDT and nano-TiO2 enhanced their capability synergistically in DNA single strand breaks of L-02 cells. The primary mechanism of toxicity may be that DDT and nano-TiO2 can induce the free radical generation, followed by DNA damage.
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