Objective To test the genotoxicity of tribromoacetic acid by cytokinesis-block micronucleus cytome (CBMN-cyt) assay.
Methods Mice L5178Y lymphoma cells were treated with tribromoacetic acid at 0 (negative control), 7.81, 15.62, 31.25, 62.50, 125.00, 175.00, and 250.00μg/mL for 24 h. The cytotoxicity was tested by tetrazolium salt colorimetric assay, and the median le thal dose (LC50) was calculated. The cells were treated with tribromoacetic acid at 0 (negative control), 31.25, 62.50, 125.00, and 175.00 μg/mL for 24 h, and plus 0.1 μg/mL mitomycin C as a positive control, and the genotoxicity was tested by CBMN-cyt assay.
Results Compared with the negative control group, the survival rate of L5178Y lymphoma cells in the 31.25, 62.50, 125.00, 175.00 and 250.00 μg/mL groups decreased significantly (P<0.05). From the dose-effect curve, a decreasing trend for the survival rate of L5178Y lymphoma cells was found with the increasing of dosage of tribromoacetic acid (P<0.01). The LC50 of tribromoacetic acid was 135.70 μg/mL. Compared with the negative control group, the frequency of micronucleus (MN) of L5178Y lymphoma cells in the 125.00 and 175.00 μg/mL groups and the nucleoplasmic bridges (NPBs) in all treatment groups increased significantly (P<0.05), but there were no differences in the frequency of nuclear buds (NBUDs) and the nuclear divided index between the treatment groups and the control group. The results of Pearson correlation test showed that along with the increasing of tribromoacetic acid treatment dosage increasing trends were found in the frequency of MN, NPBs, and NBUDs (P<0.01).
Conclusion The findings by the application of CBMN-cyt assay indicate that tribromoacetic acid could induce genotoxicity, mainly including chromosome damage, DNA error-prone repair, chromosome recombination or damage of telomere fusion.
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