中文摘要：

目的：研究甲醛和苯联合染毒对小鼠胚胎发育的影响。方法：将昆明孕鼠随机分为4组，每组10只。胚胎植入后进行不同浓度的甲醛和苯联合染毒，分别为对照组（甲醛0mg／m3、苯0mg／m3）、低剂量组[甲醛（0．10±0．01）mg／m3、苯（0．11±0．01）mg／m1中剂量组[甲醛（5．00±0．30）mg／m3、苯（5．50±0．40）mg／m3）、高剂量组[甲醛（10．00±0．50）mg／m3、苯（11．00士0．50）mg／m31，每天染毒2h，持续15d。观察孕鼠一般情况，记录其生产情况及24h存活仔鼠数目；称量仔鼠体质量、肝脏质量；并提取仔鼠肝脏总RNA，采用RT—PCR检测肝细胞中细胞周期调控基因Cdk2、CyclinE、Cdk7、Cyclin的表达情况。结果：高剂量组孕鼠平均体质量低于其余各组（P〈0．05），孕鼠、流产孕鼠数高于其他各组（P〈0．05），此外，高剂量组孕鼠产仔数及24h存活仔鼠数也低于其他剂量组，差异均具有统计学意义（P〈0．05）。细胞周期调控基因Cdk2在中剂量组、高剂量组的表达高于对照组与低剂量组，CyclinE在高剂量组的表达高于其余各组，差异具均有统计学意义俨〈0．05）。Cdk7、Cyclin日在各组中表达的差异均无统计学意义（P〉0．05）。结论：小鼠胚胎植入后，甲醛和苯联合可导致流产增加及胎鼠存活率降低，并引起仔鼠肝细胞中细胞周期调控异常。

英文摘要：

OBJECTIVE： To study the combined effects of formaldehyde and benzene on the development of mice embryo after implantation. METHODS： Pregnant mice were randomly divided into four groups and exposed to different concentrations of formaldehyde and benzene starting from embryo implantation for 15 days. The concentrations of formaldehyde and benzene were 0 mg/m3 of formaldehyde and 0 mg/m3 of benzene for control group, （0.10± 0.01） mg/m3 of formaldehyde and （0.11 ±0.01） mg/m3 of benzene for low dose group, （5.00±0.30）mg/m3 of formaldehyde and （5.50 ± 0.40） mg/m3 of benzene for medium dose group, （10.00 ± 0.50） mg/m3 of formaldehyde and （11.00 ± 0.50） mg/m3 of benzene for high dose group. The general condition of pregnant mice, number of newborns as well as 24-hour survival of newborns were recorded. The body weight of newborns along with liver weight were also recorded to calculate liver coefficient. Total RNA was extracted from liver to detect the expression of cell cycle regulatory genes, Cdk2, CyclinE, Cdk7, CyclinH, by RT-PCR. RESULTS ： The average weight of pregnant mice in high dose group was lower than the remaining groups （P〈0.05） while the number of abortion was higher （P〈0.05）. In addition, the number of newborns and 24-hour survival of newborns in the high dose group were also lower than other dose groups, and the difference was statistically significant （P〈0.05）.The expression of Cdk2 in the medium and high dose groups were stronger than that in control group and low dose group. Besides, the expression of CyclinE in high dose groups was stronger than any other groups. The difference was statistically significant （P〈0.05）. The expressions of Cdk7 and CyclinH were not statistically significant （P〉O.05） among the groups. CONCLUSION： Exposure of pregnant mice to formaldehyde and benzene after implantation could lead to abortion, the reduction of newborns and their survival. It could also cause hepatocyte cell cycle regulation abnormalities in