Objective: To study the effect of benzene on aneupoidy of oocytes and female pronucleus of one cell zygotes.
Method: The NIH adult female mice were treated with varies doses of benzene (942, 1,881 and 3,762 mg/kg respectively) via single gavage and (706, 1,922 and 4,864 mg/m3, respectively) multiple inhalation. After gavage, the mice were pair-matched (1:1) with males overnight. The ovulated oocytes and the one cell zygotes were collected for cytogenetic analysis and the frequencies of aneuploidy were detected.
Results: The frequencies of aneuploid in M II oocytes significantly increased in the three groups treated with inhalation (7.06%, 7.50% and 7.76%, respectively, control group 0.00%, P < 0.05) of benzene, as compared with those in the control group (1.30%), with a dose-dependent response. Meiotic delay of M I oocytes was observed, with the frequency of M I oocytes of 1.16%, 3.61% and 5.75%, respectively, P < 0.05, in a dose-dependent response, too. In gavage treatment group, increase in frequency of M II oocyte aneuploidy was only observed in the high-dose group, and aneupliody frequency of female pronucleus in one cell zygotes was not induced.
Conclusion: Exposure to high-dose benzene via gavage or inhalation was able to induce increase in aneuploidy frequency of M II oocytes in mice.