鼠巨细胞病毒感染C57BL/6小鼠急性肝炎动物模型的建立与鉴定

目的：建立鼠巨细胞病毒（MCMV）感染C57BL/6小鼠急性肝炎模型并对其感染特点进行分析及鉴定。方法：将24 只C57BL/6小鼠随机分为阴性对照组（n =12）及病毒感染组（n =12），病毒感染组腹腔注射1.0×106 PFU（200 μL）MCMV悬液，阴性对照组注射等体积小鼠胚胎成纤维细胞（MEF）悬液。于感染后第3天和第7天取外周血分离血清检测谷丙转氨酶（ALT）及谷草转氨酶（AST）。同时进行肝组织病毒分离、组织病理学及MCMV IE和M55基因、细胞因子白细胞介素-6（IL-6）、白细胞介素-1β（IL-1β）、肿瘤坏死因子α（TNF-α）的检测。结果：病毒感染组肝组织匀浆病毒分离均为阳性，肝炎发生率为100%。在感染后第3天即发生肝炎病理改变，病毒感染组血清ALT及AST较阴性对照组明显升高（P ＜0.01）；病毒感染组肝脏HE染色第3天可见局灶性炎性细胞浸润及肝脏点灶状坏死，持续至第7天，Ishak评分较阴性对照组明显升高（P ＜0.01）；在感染后第3天病毒感染组肝组织内可检测到MCMV IE及M55基因，且在感染后第7天仍可测得IE基因；感染后第3天及第7天病毒感染组炎性细胞因子IL-6、TNF-α及IL-1β mRNA表达水平明显升高（P ＜0.05）。 结论：成功建立MCMV感染C57BL/6小鼠急性动物肝炎模型，其感染表现主要集中在急性感染前期。

Establishment and identification of acute hepatitis animal model infected by murine cytomegalovirus in C57BL/6 mice

Objective: To establishe the acute hepatitis model of C57BL/6 mouse infected with murine cytomegalovirus (MCMV) and analyze its infectious characteristics so as to identify the model. Methods: Twentyfour C57BL/6 mice were randomized to the negative control group and virus infection group (n=12 in each). Murine cytomegalovirus (MCMV) suspension 1.0×106 PFU (200 μL) was intraperitoneally injected in the virus infection group mice, and an equivalent volume of mouse embryonic fibroblast (MEF) suspension in the negative control group. The levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested on day 3 and day 7 after infection. Meanwhile, virus isolation, histopathological analysis, detection of MCMV IE and M55 genes, interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) were performed.Results: In virus infection group, all the liver homogenates were positive for virus isolation and the incidence of hepatitis was 100%. The pathological changes of hepatitis occurred on the 3rd day after infection. Compared with the negative control group, the levels of serum ALT and AST in virus infected group were significantly increased (P<0.01). Focal necroinflammatory lesions were observed in the liver of the virus infected group on day 3 of hematoxylin-eosin staining, which lasted until day 7. Ishak score was significantly higher than that of the negative control group (P<0.01). MCMV IE and M55 genes were detectable in liver tissue on day 3 after infection, and the IE gene was still detected on day 7 after infection. The mRNA expression of inflammatory cytokines, IL-6, TNF-α and IL-1β were significantly increased on day 3 and day 7 after infection (P<0.05). Conclusion: The acute hepatitis model infected with MCMV in C57BL/6 mice was established successfully, and the infection is mainlymanifested in the early stage of acute infection.