EV71型手足口病乳鼠动物模型的建立及免疫、内分泌及病理特征研究

Immunological,endocrinological,and pathological characteristics of the EV71-BJ strain-infected suckling mice

目的建立EV71型手足口病乳鼠动物模型并进行免疫、致病特性研究。方法将临床分离的EV71病毒株经蚀斑纯化,3T3细胞适应,乳鼠驯化,最终获得1株能致死7日龄乳鼠的EV71毒株,命名为BJ09/07(GenBank Accession NO.JQ319054,EV71-BJ)。EV71-BJ感染7日龄ICR乳鼠后,观测临床疾病得分、体质量变化、死亡率并测定病毒载量、免疫分子、内分泌水平、组织病理损伤等病毒、免疫、内分泌、病理指标。结果 EV71-BJ毒株感染7日龄ICR乳鼠,其病毒毒力为150 LD50/ml,感染后不同时期肌肉病毒载量均高于脑中,至第4天达到高峰,后不断下降。至感染后第6天发病达高峰时做病理检测,相对于脑组织,肌肉中有更严重的淋巴细胞浸润,引起更严重的炎性分子升高。肌肉研磨液和血清中MCP-1、IFN-γ、IL-6和TNF-α显著升高,而肾上腺素和皮质醇未见明显变化。结论初步建立了EV71型手足口病乳鼠动物模型,为药物筛选、疫苗研发及免疫机理研究奠定了基础。

Enterovirus 71（EV71） is a major causative agent of epidemics of hand-foot-mouth disease which associates with severe neurological disease,but the mechanism of EV71 pathogenesis remains unknown.In this study,we aimed to construct EV71 infected suckling mouse model and to evaluate immunological,endocrinological,and pathological characteristics of this model.In order to construct EV71 infected suckling mouse model,the clinical isolates of EV71 were purified by plaque purification,adapted to 3T3 cells,and then used infected suckling mice.EV71-BJ strain（GenBank accession NO.JQ319054） was finally achieved,which can make 7-day-old suckling mice infection and death.After the 7-day-old suckling mice were infected,we observed the clinical disease scores,body weight changes,and mortality.On 6 days post infection,viral loads of the brains and muscles,immune molecule levels,endocrine hormone levels,and pathological damages of the brains and muscles were determined by real-time RT-PCR,cytometric bead array（CBA）,ELISA and histopathology,respectively.The virulence of EV71-BJ for 7-day-old suckling mice was 150 LD50/ml.The viral loads in muscles,with a peak on day 4 postinfection,were higher than that in brain.On 6 days post infection,more severe necrotizing myositis and infiltration of lymphocytes were observed in the mice muscles,with more significant rise of MCP-1,IFN-γ,IL-6 and TNF-α,compared with that of the mouse brains.However,no significant changes of epinephrine and cortisol were observed in the infected mice.In conclusion,an EV71 infected mouse model has been established,which will serve medicine screening,vaccines development and immunopathology researches for EV71 infection.