Abstract: BACKGROUND ＆ AIM:To study the DNA damage in bone marrow cells of mice induced by rare_earth element Holmium. MATERIAL AND METHODS: Holmium_trioxide_HCl solution was administered orally in a single treatment in a cumulative dose series to mice. The bone_marrow cells of thighbone were collected in 24 hours after treatment and performed single cell gel electrophoresis(SCGE)to determine chromosomal and DNA damage. RESULTS: The exeperiment showed that,in dosage from 20 mg/kg to 80 mg/kg, the average tail length increased highly significantly with the rise of dosage compared with the control(P<0.001),while the average head diameter diminished gradually on the contrary. In dosage from 40 mg/kg to 80 mg/kg, the average head diameter showed highly significant difference compared with the control(P<0.001). Besides,the percentage of tailed cells and ratio of damaged DNA increased with the rise of concentrations. CONCLUSION: It suggests that rare_earth element Holmium may damage DNA in bone_marrow cells of mice in some degree.

Key words: holmium trioxide, single cell gel electrophoresis (SCGE), bone_marrow cells of mice, DNA damage