人巨细胞病毒先天性感染胎鼠致肝脏损伤的小鼠模型

目的：探讨人巨细胞病毒（HCMV）先天性感染致肝脏损伤的病理机制，建立HCMV先天性感染胎鼠致肝脏损伤的小鼠模型。方法：将不同剂量的HCMV接种至10周龄Balb/c雌雄小鼠腹腔后交配，待雌鼠临产时，剖腹取出胎鼠肝脏，进行病毒分离，病理学检查和HCMV，DNA原位杂交检测。结果：在接种6．0log TCID50 HCMV组胎鼠的肝组织匀浆上清液中分离出HCMV；在病毒分离出现典型细胞病变效应（CPE）的细胞培养液中检测出HCMV DNA；原位杂交证实病毒核酸存在于肝细胞核内和胞浆内；病理学证实肝组织有炎性改变，肝细胞浊肿变性；核内有特异性HCMV包涵体，部分肝细胞呈坏死表现，3．0log TCID50组原位杂交见肝细胞核内和胞浆内有少量病毒核酸存在，病理结果表明肝组织仅有轻度炎性改变和肝细胞浊肿变性，上述表现在1．5log TCID50组均不明显，与正常对照组相似。结论：HCMV可以通过胎盘造成胎鼠的先天性感染，导致肝脏损伤，并与母体感染的病毒量有关，该模型的建立为进一步研究人类先天性HCMV感染造成肝脏损伤的病理过程以及对先天性感染的预防，诊断和抗病毒药物的筛选提供了可能。

A mouse model of congenital human cytomegalovirus infection that induces liver damage in fetus

Objective To define that human cytomegalovirus (HCMV) can cross the placenta of the Balb/c mice and induce liver damage in developing fetus. Methods HCMV AD169 (6.0 logTCID 50 , 3.0 logTCID 50 , 1.5 logTCID 50 per mouse respectively) was injected into the peritoneum of mice (half of mice were female) when they were about 10 weeks old (weight 25 30g). Then, these mice were paired to mate. Fetus on day about to give birth was removed from the uterus and liver was obtained for virus isolation, pathological studies, examination of the viral DNA positive cells by in situ hybridization using digoxigenin labelled HCMV DNA oligonucleotide probe. Results HCMV could be isolated from the supernatant of tissues; HCMV DNA was found by PCR in supernatant of cell culture with CPE; the presence of viral DNA sequence in hepatocytes was confirmed by in situ hybridization; pathological changes in liver consist of swollen cytoplasm and destroyed nuclei of hepatocytes and distinct intranuclear inclusion in hepatocytes with a cellular infiltrates of predominantly phagocytic cells. All above were found more obviously in fetal mouse liver tissues from the group inoculated with 6.0 log TCID 50 HCMV AD169 as compared with 3.0 log TCID 50 group. In contrast, these positive results couldn't be well found in 1.5 log TCID 50 group. Nothing could be found in normal controls. Conclusions Our research suggests that primary maternal HCMV infection during pregnancy could induce congenital infection in fetus by transplacental transmission and induce fetal liver damage. The mouse model will provide the basis for the study on pathogenesis of congenital HCMV infection in liver and the development of prevention, diagnosis and antiviral agents for congenital HCMV infection in human being.