果子狸SARS-CoV实验性感染的病理学研究

Experimental infection of SARS-CoV in civets:a pathological study

目的为了明确实验性感染SARS-CoV的果子狸各器官的病理变化,进一步确定SARS-CoV与果子狸的关系,评价其作为SARS动物模型的可行性。方法在人源SARS-CoV分离株BJ01(有29个核苷酸的缺失序列)和GD01(无29个核苷酸的缺失序列)实验性感染果子狸的基础上,对其经福尔马林固定的肺、脾、淋巴结、肝、小肠、肾、气管、大脑、胰腺、性腺、胃、心组织进行病理组织学观察,同时用原位杂交技术(ISH)对SARS-CoV在组织器官中的分布进行检测。结果攻毒后不同时期,肺、脾、淋巴结、肝、小肠、肾和大脑有不同程度的病理变化,主要病变是肺脏为急性间质性肺炎:肺炎性水肿、肺泡腔浆液渗出以及肺泡壁充血、出血并因淋巴细胞、巨噬细胞增生、浆液渗出而显著增厚,肺内小血管增生、扩张。淋巴结、脾脏结构破坏,淋巴滤泡消失,脾小体萎缩,淋巴细胞明显减少,结缔组织增生。肝细胞脂肪变性,并见有多个淋巴细胞浸润灶。ISH结果显示,在肺、小肠、大脑中检测到SARS-CoV基因,其它器官中未检到,与SARS患者的检测结果基本相符。结论果子狸实验性感染SARS-CoV可导致与人类相似的病理学变化和病原分布,表明果子狸可以作为评价SARS-CoV疫苗及治疗药物的动物模型。

Purpose To identify the pathological changes of experimental infection of SARS-CoV in civets, confirm the relationship of SARS-CoV and civets and evaluate the feasibility of the animal model for SARS. Methods On the base of our previously research of the susceptibility of the civets to experimental infection by two human isolates of SARS-CoV, B J01 （with a 29-nucleotide deletion） and GDO1 （without the 29-nucleotide deletion）, formalin-fixed tissues of the lung, spleen, lymph node, small intestine, kidney, trachea, cerebrum, pancreas, sex gland, stomach and heart were studied using routine haematoxylin and eosin （HE） stain and in situ hybridization （ISH） assay. Results Different degree of damages were found in different days after infection. The main lesions of the infected animals consisted of acute interstitial pneumonia and inflammatory edema of lung. Alveolar capillary were dilated and filled with blood and alveolus were filled with serous fluid mixed with lymphocytes. The adjacent blood-vessels showed hyperplasia and enlargement. The structures of lymph nodes and spleen were damaged with lymph follicles depletion and splenic nodule atrophy. The principal changes were the reduction of lymphocytes and hyperplasia of connective tissue. Hepatocyte was enlarged and cytoplasm contained larger vacuoles. Focal aggregations of a great number of lymphocyte were present in hepatic lobules. Positive signals of ISH were detected in lung, small intestine and cerebrum, but not in liver, spleen, kidney, trachea, pancreas, sex gland, stomach, and heart. The results were similar to those of suffered human. Conehtsion Pathological changes and SARS-CoV distribution in civets are most similar to those in tissues from patients who died of SARS, so civets will be a useful animal model to study the pathogenesis of SARS and to evaluate candidate vaccines, and antiviral drugs against SARS.