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.

OBJECTIVETo investigate the effects of total alkaloids of Tripterygium hypoglaucum Hutch (THH) on the tk gene of mouse lymphoma cells.

METHODL5178Y cells were infected with total alkaloids of THH with different concentrations and put into single-cell wells at different time phases. Then the numbers of positive wells were counted and the cell plating efficiency, relative suspension growth and mutation frequency were determined.

RESULTTotal alkaloids of THH (0.1-2.0 g x L(-1)) induced tk locus mutation with mutation frequency 2-9 times higher than that of spontaneous mutation frequency of L5178Y cells. There were two different phenotypes of mutation colonies, large colony and small colony, but the main colony was large colony. This phenomenon might be related with the mutagenesis of THH.

CONCLUSIONTotal alkaloids of THH can exert toxicity and mutagenic effects on tk gene in L5178Y cells, and there may be range limit in gene mutation.

Alkaloids ; administration & dosage ; isolation & purification ; toxicity ; Animals ; Cell Line, Tumor ; Cell Survival ; drug effects ; Dose-Response Relationship, Drug ; Leukemia L5178 ; enzymology ; genetics ; pathology ; Mice ; Mutagens ; administration & dosage ; isolation & purification ; toxicity ; Plants, Medicinal ; chemistry ; Point Mutation ; Thymidine Kinase ; genetics ; Tripterygium ; chemistry