The DNA Damage Induced By Roxarsone In Chinese Hamster Lung Cells By The Single-cell Gel Electrophoresis Method

Roxarsone, a organoarsenic additive, with antibiotic effect, growth promotion and improving feed efficiency, was widely used in livestock and animal production. The residues of organoarsenic compound in animal manure were run into environment because of their little absorption and most of excreated in feces as parental drug. Inorganic arsenic compound is a classical carcinogens and has DNA damage effect to organism. There is little investigation about the DNA damage and its potential genetic toxicity to live cells in the environment although the toxicity of roxarsone is lower than inorganic arsenic. In this paper, single-cell gel electrophoresis was used to demonstrate the roxarsone′s side-effect on Chinese hamster lung cells(V79 cells) DNA, and may lay basic foundation to the genetoxicity research and risk evaluation to organism in environment.The V79 cells with logarithmic growth phase were exposed to different concentration of roxarsone (1, 10, 100, 500 and 1000μg/ml) and 10μg/ml sodium arsenite in 3h, 6h, 12h, 24h and 48h exposure time respectively. The PBS solution was as control group. Based on the modified alkaline single-cell gel electrophoresis, the content of tail DNA, tail moment and olive tail moment were measured by the CASP software. Results showed the contents of tail DNA were increased 13.87%, 15.51%, 28.29%, 29.39% and 35.17% at 48h exposure time from 2.02%, 4.22%, 7.48%, 9.60% and 11.03% at 3h in 1, 10, 100, 500 and 1000μg/ml roxarsone treated respectively. The tail moment parameters were increased 1.84%, 3.11%, 4.28%, 5.06% and 7.61% at 48h exposure time from 0.12%, 0.27%, 0.81%, 0.95% and 1.44% at 3h. Olive Tail Moment parameters were increased 2.06%, 2.34%, 5.11%, 5.58% and 8.18% at 48h exposure time from 0.27%, 0.48%, 1.02%, 1.23% and 1.57% at 3h. It was clear that 1μg/ml roxarsone can induced V79 cell DNA damage at 12h expose time compared with the PBS control (P<0.05). The other roxarsone treated groups did induced DNA damage within the every exposure time (P<0.05). The DNA damage level of 500μg/ml and 1000μg/ml roxarsone were almost equal to the effect of 10μg/ml sodium arsenite to V79 cells. The micronucleus test of roxarsone to V79 cells appeared obviously micronucleus rate post 12 hours exposure time except the 1μg/ml roxarsone treatment, but the time detected DNA damage was later than the single-cell gel electrophoresis method.The single-cell gel electrophoresis and micronucleus test were detected the DNA damage of to V79 cells , and the former could detect earlier cell DNA damage , implying that roxarsone in environment with the animal excrement fertilizer might exist the potential genetic toxicity risk for environment biological life. The single-cell gel electrophoresis could be used as a effective method to detect the DNA damage of organoarsenic compound in environment.