Abstract：Objective To investigate the genetic toxicity of methyl tert-butyl ether （MTBE） to lymphocytes and to provide reference for establishing the occupational population exposure limit of MTBE. Methods The human B lymphocytes in the logarithmic growth phase were respectively exposed to MTBE at concentrations of 0,1.25,2.5,5,10 and 12.5 μmol/L. The percentage of tail DNA and Olive tail moment of human B lymphocytes were evaluated after 24 h exposure by using comet assay. Apoptosis was tested by Annexin V-FITC/PI double-staining flow cytometry. The contents of MDA and 8-OHdG,as well as GSH-Px activity were measured by ELISA kit. Sixty workers from a petrochemical factory in Zhejiang were selected as the occupational exposure population,and 55 non-occupational exposure workers were selected as the control population. And 5 mL heparin anticoagulant peripheral blood was collected,and the number of micronucleus of peripheral blood lymphocytes was measured by micronucleus test,and the percentages of tail DNA as well as Olive tail moment of peripheral blood lymphocytes were measured by comet assay. The contents of MDA and 8-OhdG and GSH-Px activity in peripheral blood plasma were measured by ELISA kit. Results After 24 h exposure,the percentage of tail DNA and Olive tail moment in human B lymphocytes at concentrations of 10-12.5 μmol/L were significantly higher than those in the control group（P<0.05）,and the percentage of early apoptosis cells was significantly increased at concentrations of 10-12.5 μmol/L （P<0.01）. The results of population-based study indicated no statistically significant difference in micronucleus positive rate,and the contents of MDA and 8-OhdG,and GSH-Px activity between the exposure group and the control group,but the Olive tail moment was significantly higher in the exposure group compared with the control group（P=0.000）. Conclusion The results of vitro study showed that exposure to 10-12.5 μmol/L MTBE could cause genetic toxicity to human B lymphocytes. Olive tail moment of peripheral blood lymphocytes of occupational exposure workers was significantly higher than that of non-occupational exposure group.
