中文摘要：

目的：观察HBV转基因小鼠孕期使用拉米夫定对降低母血HBV含量的作用及其对母胎安全性的影响，探讨孕期采用HBV抗病毒治疗，降低宫内感染发生率的可行性。方法：应用可高水平表达HBsAg的HBV转基因小鼠，分别从孕早期（孕第5天）和孕中期（孕第10天）开始给予拉米夫定（100mg／kg／天）直至分娩，对照组给予生理盐水。检测母鼠血中HBsAg、HBVDNA等感染指标的变化，同时从多阶段、多方面，用多指标观察妊娠期，尤其是妊娠早期，使用药物对母鼠、胎鼠及新生鼠安全性的影响。结果：21只孕期接受抗病毒药物的HBV转基因母鼠，无一例发现明显的毒性反应，对胎鼠无致畸作用，且不影响新生鼠早期生长发育，同时小鼠病毒DNA水平明显下降。结论：HBV转基因小鼠孕期服用拉米夫定可降低病毒负荷，有助于减少HBV母婴传播的危险性，且对母鼠及其子代的安全性无明显影响。

英文摘要：

Objective： To study the efficacy of lamivudine （3TC） for decreasing the amount of HBV DNA in maternal blood and the safety of mother and fetus by HBV transgenic mice with pregnancy, and to provide animal experiment bases for the use of lamifudine in antiviral therapy of HBsAg positive mother during pregnancy, especially those in early pregnancy by evaluating the efficacy and safety of lamivudine therapy, and to investigate the practicability of preventing intrauterine infection with antiviral therapy in pregnant women. Methods： The transgenic mice with high levels of hepatitis B virus were employed for the first time to study the antiviral effect of lamivudine during the different gestation.21 transgenic mice with replication high levels of hepatitis B virus were randomly divided into 3 groups.Each group had 7 transgenic mice. HBV transgenic pregnant mice in experiment group 1 and experiment group 2 were given orally lamivudine （100mg/kg） once a day from pregnancy day 5 or 10 to delivery. Seven mice in control group were received normal saline 0.5ml·d-1. The changes of serologic HBV markers were detected, at the same time, the effects of the medicine on mother and fetus,especially during the early gestation, were observed. Results： For the 21 experimental mice,the serum HBV DNA titers were lower significandy after 3TC treatment and no toxicity reaction occurred;fetal mice had no teratogeny;and besides,the early growth and development of newborn mice were not affected. Conclusion： 3TC treatment during gestation could reduce the levels of HBV DNA in HBV transgenic pregnant mice, which was helpful to preventing HBV intrauterine infection, and had no significant effect on the safety of mice and offsprings.