OBJECTIVETo study the damage effect of benzene on DNA and its mechanism and the changes of antioxidative enzymes in vivo.

METHODSDNA break in bone marrow cells and peripheral blood lymphocytes of mice exposed to benzene by 4 h static inhalation per day at different concentrations for two months were analyzed with single cell gel electrophoresis (SCGE). Meanwhile, the activity of SOD, GSH-Px and the level of MDA in liver, spleen and brain were detected.

RESULTSIn low and high dosage groups, the rate of DNA migration of bone marrow cells (83.56% +/- 10.28%, 92.54% +/- 15.93%) and peripheral blood lymphocytes (41.27% +/- 6.03%, 65.79% +/- 11.62%) were higher than those in control (4.13% +/- 0.52% and 2.21% +/- 0.31% respectively, P<0.05]. The activity of SOD in liver [(754.33 +/- 116.30), (694.26 +/- 116.30) U/mg pro] and GSH-Px [(22.52 +/- 3.31), (18.56 +/- 4.97) U/mg pro] were lower than those in control [(999.92 +/- 188.24) and (35.31 +/- 6.63) U/mg pro respectively, P<0.05, P<0.01]. But there was no significant difference between the two dosage groups. The activity of GSH-Px in spleen of both groups [(31.38 +/- 2.71), (25.30 +/- 7.44) U/mg pro] were lower than that of control [(37.11 +/- 3.42) U/mg pro, P<0.05] and there was significant difference between the two dosage groups. The activity of GSH-Px in brain of both groups [(5.70 +/- 0.84), (5.24 +/- 1.19) U/mg pro, P<0.05] were lower than that of control [(7.10 +/- 0.46) U/mg pro, P<0.05], but there was no significant difference between the two dosage groups. The level of MDA in brain of high dosage group [(3.99 +/- 1.15) nmol/mg pro] was higher than that of control [(2.58 +/- 0.53) nmol/mg pro, P<0.05].

CONCLUSIONChronic benzene poisoning may result in DNA break in bone marrow cells and peripheral blood lymphocytes and decrease in the activity of antioxidative enzymes.