人类淋巴母细胞TK6检测环磷酰胺诱发微核及TK基因突变的体外实验研究

Micronuclei and Gene Mutation at tk Locus Induced by Cyclophosphamide in TK6 Human Lymphoblastoid Cells

目的建立TK6细胞检测环境诱变剂诱发微核及TK基因突变的实验方法。方法用诱变剂环磷酰胺(CP)体外染毒TK6细胞4h后检测细胞毒性,微核及tk位点突变频率。结果CP处理导致TK6细胞的相对存活率下降,细胞微核率及TK基因突变频率明显上升,并均有剂量-反应关系。最高浓度组(4.0μg/ml)的细胞微核率及TK基因突变频率分别是对照组的8.8和15.7倍。CP诱发tk位点两种不同表型的突变细胞集落,即正常生长突变体集落及缓慢生长突变体集落,并以后者为主。结论CP可以诱发TK6细胞微核及TK基因突变,揭示CP可能是一种断裂剂。TK6细胞可用于评估环境化学物细胞水平遗传改变及TK基因突变。

Objective To establish a method to investigate micronuclei (MN) and gene mutation at the heterozygous thymidine kinase (tk) locus induced by environmental mutagens in TK6 human lymphoblastiod cells. Methods TK6 cells were used to detect cytotoxic response, MN and mutation frequency at tk locus induced by cyclophosphomide (CP) after treatment with S9 mixture for 4 h. Results Exposure to CP for 4 h decreased relative survival (RS), induced both MN and TK mutation in a concetration-dependent manner. The maximum induction of MN and TK mutations were 8.8 and 15.7 times compared with those of control. Two distinct phenotypic colonies of TK mutants were generated, namely tk-NG and tk-SG mutant colonies but mainly the latter. Conclusion CP induced both MN and TK mutation in TK6 cells. TK6 cells can be used as an in vitro assay system to assess cytogenetic damage and gene mutation at tk locus of environmental chemicals.