结核分枝杆菌感染小鼠模型的建立与评价

Creation and evaluation of mouse models for Mycobacterium tuberculosis infection

目的建立结核分枝杆菌感染的小鼠模型,分析感染小鼠重量指数、组织荷菌量、组织病理改变随感染时间的变化。方法以1.1×105菌落形成单位(CFU)的结核分枝杆菌标准株H37Rv经尾静脉感染50只雌性BALB/c小鼠,于感染后1、2、3、4、8周杀鼠,每个时间点剖杀10只,观察肺组织病理改变并称重,计算重量指数,同时做肺和肝菌落计数。结果感染1、2、3、4、8周小鼠的肺脏器重量指数分别为0.0112±0.0036、0.0101±0.0071、0.0112±0.0046、0.0151±0.0057和0.0198±0.0069,差异有统计学意义(F=4.24,P<0.01);肝脏器重量指数分别为0.0558±0.0059、0.0591±0.0094、0.0569±0.0076、0.0582±0.0030和0.0619±0.0079,差异无统计学意义(F=0.86,P>0.05);脾脏器重量指数分别为0.0107±0.0034、0.0146±0.0060、0.018±0.0034、0.0174±0.0026和0.0204±0.0066,差异有统计学意义(F=4.01,P>0.05);肺菌落数分别为(4.472±0.504)log、(5.539±0.429)log、(6.294±0.478)log、(6.250±0.315)log和(6.836±0.196)log,差异有统计学意义(F=43.90,P<0.01)。感染后1周小鼠肺组织可见病理改变,且随着感染时间的增加病变范围逐渐扩大,病变程度逐渐严重。结论成功建立了结核分枝杆菌感染小鼠模型,该模型可用于结核疫苗和药物研究。

Objective To establish a mouse model for Mycobacterium tuberculosis infection and analyze changes in organ weight indices and bacterial load and histopathological changes in mouse tissues over time. Methods Fifty female BALB/c mice were infected intravenously with approximately 1.1×10^5 colony forming units（CFU）of M.tuberculosis H37 Rv.Ten mice were euthanatized 1,2,3,4,and 8weeks after infection.The mice and their lungs,spleens,and livers were weighed,and then the weight indices of lungs,spleens,and livers were calculated.The lungs and livers were homogenized and plated to determine the bacterial load.The lungs were fixed in buffered formalin and embedded in paraffin,and tissue sections were prepared with hematoxylin and eosin to observe pathological changes. Results The weight index of the lungs was 0.0112±0.0036 1week after infection,0.0101±0.0071 2weeks after infection,0.0112±0.00463 weeks after infection,0.0151±0.0057 4weeks after infection,and 0.0198±0.0069 8weeks after infection.The weight index of the lungs was significantly higher 8weeks after infection than it was 1,2,3,and 4weeks after infection（F=4.24,P=0.0054）.The weight index of the liver was 0.0558±0.0059 1week after infection,0.0591±0.0094 2weeks after infection,0.0569±0.0076 3weeks after infection,0.0582±0.0030 4weeks after infection,and 0.0619±0.0079 8weeks after infection.The weight index of the liver was higher 2,3,4,and 8weeks after infection than it was1 week after infection,but the difference was not significant（F=0.86,P=0.4981）.The weight index of the spleen was 0.0107±0.0034 1week after infection,0.0146±0.0060 2weeks after infection,0.018±0.0034 3weeks after infection,0.0174±0.0026 4weeks after infection,and 0.0204±0.0066 8weeks after infection.The weight index of the spleen was significantly higher 2,3,4,and 8weeks after infection than it was 1week after infection（F=4.01,P=0.0073）.The bacterial load in the lungs was 4.472±0.504 log CFU/g 1week after infection,5.539±0.429 log CFU/g 2weeks after infection,6.294±0.478 log CFU/g 3weeks after infection,6.25±0.315 log CFU/g 4weeks after infection,and6.839±0.196 log CFU/g 8weeks after infection（F=43.90,P〈0.01）.Pathological changes in the lungs occurred 1week after infection,the extent of lesions in the lungs increased,and pathological changes worsened as the duration of in-fection increased. Conclusion A mouse model of Mycobacterium tuberculosis infection was successfully established.This model may provide a basis for study of vaccines and drugs to treat Mycobacterium tuberculosis.