Abstract: Purpose : To study and compare DNA injuries and repair in BALB/ C mice splenic lymphocyte induced by exogenous cadmium2metallothionein (CdMT) . Methods :Single cell gel elect rophoresis ( SCGE) assay was sed to detect DNA single st rand breaks (DNA2SSBs) when lymphocyte were induced with different concent ration of CdMT for 30 or 60 minutes , and the ability of DNA repair after CdMT was removed for different times from 30 to 120 minutes respectively. Results : It was showed that the comet length of DNA-SSBs did not found change in Apo2MT group , while there were significant increasement of the comet length in mid2 or high-dose CdMT group at both exposure times. And the comet length of each DNA repair times (30 to 120 min) in mid2 or,high-dose CdMT group was significantly shorter than that of DNA injuries , but longer than that of cont rol and Apo2MT group. Conclusion : It is indicated that lymphocyte DNA2SSBs damage would be induced by CdMT exposed directly , and that there were repair activity for DNA2SSBs in spleen lymphocyte in vit ro.

Key words: metallothionein, cadmium, DNA injury and repair, single cell gel elect rophoresis