人 H7N9禽流感病毒与 H1 N1流感病毒感染小鼠病理学损伤的比较

Comparison of pulmonary pathological changes in mice infected with H7N9 influenza virus and pandemic H1N1 influenza virus

目的比较分析H7N9病毒与H1N1病毒感染小鼠病理学损伤特点,初步探讨两种病毒感染致小鼠急性肺损伤的致病机制。方法 H7N9病毒与H1N1病毒分别感染小鼠,观察不同病毒感染后小鼠生存率,并于不同时间点取心、肝、脾、肺、肾、脑、肠等组织,伊红-苏木素染色并进行组织病理学分析,免疫组化检测病毒抗原分布及中性粒细胞浸润。综合分析肺组织病理损伤与病毒复制、宿主免疫反应之间的关系。结果 H7N9病毒感染小鼠肺及脾脏损伤较轻,存活率较高。H1N1病毒感染的小鼠肺及脾脏损伤较重,感染后9 d全部死亡;两种病毒抗原主要分布于支气管上皮细胞、少量间质细胞和肺泡上皮细胞,病毒复制水平无明显差异。但H1N1病毒感染后肺及脾脏中均有大量中性粒细胞浸润,小鼠机体炎症反应明显强于H7N9病毒感染后小鼠炎症反应。结论 H7N9病毒与H1N1病毒感染后小鼠病理学损伤特点及程度均不同,病毒复制是小鼠肺损伤的诱发因素但并非决定因素,宿主针对病毒感染产生的免疫反应程度与急性肺损伤密切相关。

Objective To analyze and compare the pathological changes of lung tissue in mice infected with the novel H7N9 influenza virus and 2009 pandemic H1N1 influenza virus, respectively, and to preliminarily study the mecha-nisms of acute lung injury induced by those virus infection .Methods SPF 6-week old BALB/c mice （ body weight 18-20 g, male∶female=1∶1） （n=3 in each subgroup） were intranasally infected with H7N9 virus and H1N1 virus, respec-tively.The behavior and survival time of mice after virus infection were observed and the survival rates were analyzed .The heart, liver, spleen, lung, kidney, intestines, and brain were collected at indicated time points for histopathological exami-nation using H＆amp;E staining .The distribution of virus antigen was detected by immunohistochemistry .The neutrophil infiltra-tion was also observed .The correlation of lung injury with virus replication and host immune responses was analyzed .Re-sults The lung and spleen injury of mice infected with H 7N9 virus was slighter and their survival rate （100%） was high-er than those of mice infected with H1N1 virus.The damages of the lung and spleen in H1N1virus-infected mice were more severe than that in H7N9 virus-infected mice, and all the 10 mice in this group died within 9 days after virus inoculation . The distributions of both the virus antigens were mainly in the bronchial epithelial cells , a few stromal cells and alveolar ep-ithelial cells .The levels of virus replication in the two groups were not significantly different .There were more intense neu-trophil infiltration in the lung and inflammatory response in the H 1N1 virus-infected mice than those in the H7N9 virus-in-fected mice .Conclusions There are some differences of the pathological characteristics and extent of lung injury in the mice infected with H7N9 virus and H1N1 virus, respectively.The virus replication is a precipitating factor but not the deci-sive factor of the lung injury , and there is a close relationship between the host immune responses and acute lung injury .