脑心肌炎病毒(EMCV)感染昆明小鼠模型的建立

Establishment of Kunming mouse model of encephalomyocarditis virus(EMCV)infection

目的:建立EMCV感染昆明小鼠模型。方法:6~8周龄昆明小鼠,雌雄各半,分为空白对照组和EMCV高(100TCID50/20 g)、中(10 TCID_(50)/20 g)、低(1 TCID50/20 g)剂量组。分别于EMCV感染5 d、7 d、9 d、11 d、13 d、15 d称重,眼眶采血后,断颈处死。取心、脑、肝和脾组织,计算各器官脏器指数;qRT-PCR检测心、脑、脾、肝和外周血病毒载量;qRT-PCR检测心和脑IL-1β、IL-6和TNF-α mRNA表达量;取心和脑,HE染色后观察组织病理损伤。结果:与空白对照组相比,高剂量的EMCV感染小鼠5 d时,能显著提高心脏指数(P<0.05)和极显著提高脾脏指数(P<0.01);qRT-PCR结果显示EMCV感染9 d时,小鼠心、脑、肝、脾和外周血病毒载量最高,中、低剂量EMCV感染小鼠各脏器中的病毒载量很低;高剂量的EMCV感染小鼠9 d时,心和脑IL-1β(P<0.01)、IL-6(P<0.001)和TNF-α(P<0.01)极显著升高;9 d时,高剂量EMCV引起心脏组织炎症细胞浸润和空泡化病变;5~9 d时,高剂量EMCV引起脑组织脑膜增厚、脑膜下血管扩张和出血、脑白质血管扩张形成血管套。结论:EMCV攻毒剂量为0.2 ml 100 TCID_(50)/20 g时,成功建立EMCV感染昆明小鼠模型。

Objective:To establish a Kunming mouse model of encephalomyocarditis virus(EMCV)infection.Methods:Kunming mouse aged 6~8 weeks,half male and female,were divided into control group and EMCV high(100 TCID50/20 g),medium(10 TCID50/20 g)and low(1 TCID50/20 g)doses groups.The mice were weighed on 5 d,7 d,9 d,11 d,13 d and 15 d of EMCV infection.After blood was collected from the orbit,the rats were sacrificed by severed neck.The organ indexes of the heart,brain,liver and spleen were calculated;qRT-PCR was used to detect the viral loads in the heart,brain,spleen,liver and peripheral blood;qRT-PCR was used to detect the expressions of IL-1β,IL-6 and TNF-αmRNA in the heart and brain;HE staining was used to observe the pathological damage of heart and brain tissues.Results:Compared with the control group,high dose of EMCV could significantly increase the heart index(P<0.05)and extremely significantly increase spleen index(P<0.01)when mice were infected with EMCV for 5 d;results of qRT-PCR showed that the viral loads in the heart,brain,liver,spleen and peripheral blood of mice were the highest at 9 d after high-dose EMCV infection,and the viral loads in various organs of mice infected with medium and low doses of EMCV were very low;when high-dose EMCV infected mice for 9 d,the levels of IL-1β(P<0.01),IL-6(P<0.001)and TNF-α(P<0.01)in heart and brain were significantly increased;high-dose EMCV infection for 9 d caused infiltration of inflammatory cells and vacuolated lesions in cardiac tissues.High-dose EMCV infection for 5~9 d caused thickening of the meninges in the brain tissues,dilation and hemorrhage of submeningeal blood vessels,dilation of white matter blood vessels and the formation of vascular sleeves.Conclusion:When the EMCV infection dose is 0.2 ml 100 TCID_(50)/20 g,the Kunming mouse model of EMCV infection is successfully established.