Hepatocarcinogenesis in transgenic mice carrying hepatitis C virus cDNA

1转基因小鼠的表达分析我们分析了5株携带丙型肝炎病毒全基因组的转基因小鼠，其中A44、A39和A48在小鼠白蛋白增强子/启动子控制下，S2和S5在SR_α启动子下。17只A44中有1只在12个月龄时肝脏表达了丙型肝炎病毒，在21个月龄时有12只在肝脏中表达。A39和A48的所有小鼠都在肝脏中表达了丙型肝炎病毒转基因，但S2和S5没有表达。实时定量聚合酶链式反应显示，在1μg的总RNA中有50~4 000个拷贝的HCVRNA表达。丙型肝炎病毒mRNA的表达似乎定位于肝组织。在肝脏中检测到的丙型肝炎病毒核心蛋白低于检出限(5pg/mg蛋白)。这些转基因小鼠A39、A44和A48的丙型肝炎病毒表达水平与慢性丙型肝炎患者相似，这与其他高表达丙型肝炎病毒的转基因小鼠不同。2.…组织学检查A39、A44和A48转基因小鼠肝脏内可见较多的炎性细胞浸润和点状坏死。21个月龄时，A39和A44组小鼠的斑点状坏死灶数量显著高于非转基因小鼠。转基因和非转基因小鼠肝脏脂肪含量变化不明显。直到21个月龄才出现肝纤维化和肿瘤性病变。3转基因小鼠肝脏的分子发病机制实时定量RT-PCR显示，在转基因小鼠肝脏中，干扰素诱导基因和细胞周期相关基因等mRNAs表达上调，这在丙型肝炎患者中观察到，因此，这些转基因小鼠类似于弱肝炎患者。然而，小鼠的抗病毒免疫反应远低于患者，提示在这些丙型肝炎转基因小鼠中引入抗病毒免疫系统是建立肝癌发生模型的必要条件。较少

1 Expression analysis of transgenic miceWe analyzed 5 lines of transgenic mice carrying the whole genome of hepatitis C virus (HCV); A44, A39 and A48 were controlled under the mouse albumin enhancer/ promoter; S2 and S5 were under the SR_α promoter. The HCV mRNA was expressed in the liver of one of 17 A44 at the age of 12 months and 12 of 17 A44 at the age of 21 months. All mice of A39 and A48 expressed the HCV transgene in the liver, but both S2 and S5 did not. The mRNA was 9.4 kb in length, and the real-time PCR revealed that 50 to 4000 copies of HCV RNA were expressed in 1 μg of total RNA. The expression of HCV mRNA seemed to be localized in the liver tissue. Less than the detection limit of HCV core protein (5 pg/mg protein) was detected in the liver. These transgenic mice A39, A44 and A48 showed the similar level of HCV expression to that of patients with chronic hepatitis C, that is different from other transgenic mice with the high level of HCV expression.2 Histological examinat … More ion of transgenic mouse liverInflammatory cell infiltration and spotty necrosis were observed in transgenic mouse liver of A39, A44 and A48. The number of spotty necrosis foci was significantly higher in A39 and A44 than non-transgenic mice at the age of 21 months. The fatty change of liver was not significant between transgenics and non-transgenics. Liver fibrosis and tumorous lesion were not observed until 21 months old. HCV antibodies were not detected in serum of the mice.3 Molecular pathogenesis of transgenic mouse liverReal-time RT-PCR of mRNA revealed that mRNAs such as interferon-inducible genes and cell cycle-related genes were up-regulated in transgenic mouse liver, that is observed in patients with HCV infection.Thus, these transgenic mice were similar to patients with weak hepatitis. Anti-viral immune response of the mice, however, was so much less than that of patients, suggesting that the introduction of anti-viral immune system to these HCV transgenic mice should be required for establishing a model of hepatocarcinogenesis. Less