Abstract: OBJECTIVE: To explore the changes of superoxide dismutase (SOD) activity，DNA damage and apoptosis of cultured rat Sertoli cells after exposure to 2，2’，4，4’，5-hexachlorobiphenyl (PCB153) ，and the effect of N-acetyl-L-cysteine (NAC) pre-treatment. METHODS： Sertoli cells were isolated from 18- to 20-day-old male Sprague-Dawley rats. Contaminated groups were exposed to PCB153 at the doses of 10，20，30 μmol/L. NAC group was pre-treated with 300 μmol/L NAC for 1h，then exposed to 30 μmol/L PCB153. Control group was exposed to DMSO with the volume equal to the highest concentration of PCB153. Then all groups were cultured for 24 h. SOD activity，DNA damage，apoptosis and morphological examination were determined by SOD assay kit，comet assay，flow cytometry and fluorescence photomicrographs，respectively. RESULTS：After 24 h exposure，SOD activity decreased as the PCB153 dose increased，significant difference was observed between 20，30 μmol/L groups and control group. NAC pre-treatment was able to increase the activity of SOD. No significant difference was observed between treated groups and control group for comet assay. There was a significant dose -response relationship between the level of PCB153 exposure and the apoptotic rate，NAC pre-treatment was able to decrease the apoptotic rate. CONCLUSION： PCB153 in the concentration of 10-30 μmol/L was able to decrease the activity of SOD and induce apoptosis in cultured rat Sertoli cells，while DNA damage was not evident. NAC pre-treatment has protective effect on SOD activity and apoptosis.

Key words: PCB153, Sertoli cells, SOD activity, comet assay, apoptosis