新型冠状病毒感染金黄地鼠模型的建立

Establishment of syrian golden hamsters model infected with Prototype strain of SARS-CoV-2

目的 建立新型冠状病毒(SARS-CoV-2)原型株(WIV04)感染的金黄地鼠动物模型。方法 利用WIV04攻毒感染不同周龄段(8、9、16、28周龄)地鼠,观察周期为14 d,每天观察动物状态、监测动物体重,分别于感染后第2、5、7 d采集地鼠组织,检测病毒核酸拷贝数及病毒滴度,组织病变情况及新冠病毒核蛋白在组织中的表达丰度。另设置不同病毒梯度攻毒感染5周龄和8周龄地鼠,第2、5 d取相关组织进行上述指标的检测。结果 地鼠在感染后第2 d体重开始下降,第5~6 d体重降到最低点,第7 d体重开始恢复。感染前期地鼠出现嗜睡、弓背等症状,感染后期恢复至正常状态。感染后第2、5 d,地鼠肺部组织均可检测到病毒核酸,心脏、肝脏、脑组织能检测少量的病毒核酸,感染后第2 d地鼠鼻甲组织中检测到较高病毒滴度。组织病理检查感染地鼠均出现不同程度的肺水肿、肺实质病变,病变组织检测到病毒抗原表达。结论 成功建立了新型冠状病毒SARS-CoV-2攻毒感染金黄地鼠动物模型,感染地鼠出现嗜睡,体重下降等临床特征,肺部组织检测到较高载量的病毒核酸,并有实质性病变。

Objective To establish an animal model of golden syrian hamsters infected with novel coronavirus(SARS-CoV-2) prototype strain(WIV04).Methods Firstly,Different ages(8、9、16、28 Weeks old)of syrian golden hamsters were infected with SARS-CoV-2 prototype strain.The observation period was 14 days.The weight of animals was monitored every day and the clinical symptoms of animals were observed.Secondly,tissue samples of hamsters were collected on the 2^(nd),5^(th) and 7^(th)day post infection(dpi).After the collected tissue samples were processed accordingly,the viral nucleic acid copy and viral titer were detected by QPCR and micro cytopathogenic effect assay respectively.The pathological changes and the expression abundance of SARS-CoV-2 nucleoprotein in lung tissue were detected by HE staining and immunohistochemistry,respectively.In addition,hamsters aged 5 weeks and 8 weeks were infected with different virus gradient challenged doses,and relevant tissues of hamsters were taken on the 2^(nd)and 5^(th)dpi for detection of the above indicators.Results The weight of hamsters begin to decline on the 2^(nd) dpi,drop to the lowest point on the 5^(th) to 6^(th) dpi,and begin to recover on the 7^(th)dpi.In the early stage of infection,the hamsters appeared lethargy,hunched back and other symptoms,and recovered to normal state in the later stage of infection.On the 2^(nd)and 5^(th)dpi,viral nucleic acid can be detected in lung tissue,and only a small amount of viral nucleic acid can be detected in heart,liver and brain tissue.And high viral titer can be detected in turbinate tissue on the 2^(th)dpi.Pathological examination of lung tissue shows that infected hamsters have pulmonary edema and lung parenchyma lesions of varying degrees,and viral antigen expression is detected in the diseased tissues.Conclusion In this experiment,the golden syrian hamster model infected by SARS-CoV-2 is successfully established.The infected hamsters show clinical features such as lethargy and weight loss.A higher load of viral nucleic acid is detected in the lung tissue,accompanied by substantial lesions.