染色体断裂剂和纺锤体损伤剂诱发的有微核的嗜多染红细胞的细胞学比较观察

A COMPARATIVE OBSERVATION IN CYTOLOGY OF MICRONUCLEI OF POLYCHROMATIC OF MICRONUCLEI OF POLYCHROMATICERYTHROCYTES INDUCED BY CLASTOGENS AND SPINDLE POISONS

以染色体断裂剂：丝裂霉素Ｃ和环磷酸胺以及纺锤体损伤剂：长春新碱和秋水仙碱四种受试物分别进行小鼠骨髓微核试验．实验结果表明，两类诱变剂所诱发的大微核形成率之‘间有非常显著的差别（Ｐ＜０．０１），显示了微核形成的不同机理．本方法对快速鉴别染色体断裂剂和纺锤体损伤剂具有一定的应用价值．

Four chemicals were selected for the mouse bone-marrow micronucleustest: Mitomycin C (3mg / kg) and cyclophosphamide (50mg / kg) are clastogens; vincristine(0.125mg / kg) and colchicine (1mg / kg) are spindle poisons. Five mice were used for eachindividual experiment. Animals were killed by cervial dislocation 24h or 30h after thetreatment. Bone marrow cells from the femurs were flushed and slides were prepared by theconventional methods. For each set of 5 mice, 3000 micronucleated polychromaticerythrocytes (MNPCEs) were counted to determine the incidence of MNPCEs per 1000PCEs (MNPCEs‰ ) and the frequency of PCEs (PCEs%). Diameters of both themicronuclei (d) and the main nuclei (D) were measured with micrometer microscope at thetime of scoring. The percentage of PCEs with large micronuclei (d ≥1 / 4D) was calculated.When relative sizes of micronuclei and the main nuclei were estimated, statistical treatmentof.the data confirmed a significant difference in size distribution of the micronuclei inducedby clastogens and spindle poisons (p<0.01). That indicated the two differentactionmechanisms of micronuclei formation, and may provide a useful method to rapidlyassess the ability of chemicals to induce aneuploidy or chromosome breaks.