钬化物诱导小鼠骨髓细胞微核和DNA损伤的研究

目的 探讨钬化物对小鼠骨髓细胞的遗传毒性.方法 昆明种纯系小鼠分为氧化钬实验组和硝酸钬实验组.氧化钬实验组设5个暴露组和1个阴性对照组（生理盐水）,给小鼠灌胃氧化钬盐酸溶液0、10、20、40、80、160 mg/kg2次,间隔24h,末次灌胃24 h后取股骨骨髓细胞制备微核片.硝酸钬实验组设3个暴露组和1个阴性对照组（生理盐水）,给小鼠腹腔注射硝酸钬溶液10、40、80mg/kg2次,间隔24 h,末次注射24 h后取股骨骨髓细胞制备微核片,同时进行单细胞凝胶电泳试验,氧化钬和硝酸钬实验组共用1个阳性对照组（环磷酰胺,CP）.除阳性对照组为6只小鼠外,其余各组均为8只,各组小鼠雌雄各半.结果 在10～80 mg/kg范围内,两种钬离子溶液均能诱导微核率随着剂量的递增而升高;在160 mg/kg时,微核率低于阴性对照组;同时,核异常的数量和程度随着剂量的增加呈现上升趋势.单细胞凝胶电泳结果表明,在10～80 mg/kg剂量范围内,彗星细胞尾长随着剂量的递增而增长（P＜0.001）,头长随剂量的递增而缩短,而拖尾率随着剂量的增加而升高.结论 钬化物对小鼠骨髓细胞具有一定的遗传毒性,DNA断裂作用可能是其分子机制之一.

A Study on Micronuclei and DNA Damage of Bone Marrow Cells of Mice Induced by Holmium Ions of Rare Earths

Objective To investigate the genotoxicity of heavy rare-earth holmium to bone-marrow cells of mice.Methods Kunming mice were randomly divided into six groups and were given holmium-trioxide-HCl by gavage at several doses of 0,10,20,40,80 and 160 mg/kg bw respectively one time a day for two days;other Kunming mice were randomly divided into 3 groups and holmium nitrate was given i.p.at doses of 10,40 and 80 mg/kg bw respectively one time a day for two days.24 hours after the last treatment,the bone-marrow cells of thighbone were collected for micronuclei analysis and single cell gel electrophoresis (SCGE).Results Frequencies of micronuclei were increased by the 2 kinds of holmium solutions at the dosage from 10 to 80 mg/kg bw with a dose-effect relationship,but at the dose of 160 mg/kg bw,it was lower than the negative control.In SCGE,the average tail length increased significantly (P<0.001) and the percentage of tailed cells also increased as dosage increased compared with the negative control,but the average head diameter decreased gradually on the contrary.Conclusion Holmium ions of rare earths have genotoxicity to bone-marrow cells of mice,and DNA breakage may be one of its molecular mechanisms.