不同感染途径建立的结核分枝杆菌急性肺感染小鼠模型的比较

Comparison of acute Mycobacterium tuberculosis infection mouse models established by different infectionroutes

目的比较3种不同感染途径建立的结核分枝杆菌急性肺感染小鼠动物模型，为结核病研究中动物模型的建立、选择与实际应用提供实验依据。方法将结核分枝杆菌标准株H37Rv稀释至1×10。菌落形成单位（cfu）／mL，分别采用尾静脉注射、滴鼻、气雾攻击方式感染小鼠，感染后6周，观察肺组织病变情况、菌落计数，肺组织行HE染色、抗酸染色，免疫组织化学检测肺组织TNF-a单位面积表达量。数据行t检验。结果气雾攻击组、滴鼻组和尾静脉组小鼠肺部结核分枝杆菌数分别为（6．290±0．028）、（6．150±0．021）和（6．120±0．008）lgcfu／mL，对照组肺部无结核分枝杆菌；各感染组与对照组比较，差异均有统计学意义（t-3．762，P〈0．01），但不同感染途径感染组间差异无统计学意义（P〉0．05）。各感染组小鼠肺组织均有病理学改变，抗酸染色阳性。单位面积TNF-a表达量在尾静脉注射组、滴鼻组和气雾攻击组分别为0．049×10^6、0．759×10^6和1．042×10^6，差异有统计学意义（t=2．504，P〈0．05）。结论气雾攻击感染方式建立的小鼠急性肺结核病模型较尾静脉注射和滴鼻方式更为有效。

Objective To compare three types of acute Mycobacteriurn tuberculosis infection mouse models established through different infection routes and to set up the theoretical basis for further developing, selecting and applying these animal model in the tuberculosis-related research. Methods Standard strain of Tubercle bacillus H37Rv was diluted to 1×106 colony forming unit （cfu）/mL. The mice were infected with the bacteria through different routes including intravenous injection, intranasal administration and inhalation of bacteria aerosol. Six weeks after the infection,the mice were euthanized and necropsied. The lung tissues were collected and gross changes were observed. The colony counting was performed and the lung tissues were assessed by HE staining, acid fast staining. The expression level of tumor necrosis factor （TNF）-a per unit area in lung tissue was detected by immunohistochemistry. The data were analyzed by t test. Results The amounts of Mycobacterium tuberculosis in lung tissues of mice in inhalation group, intranasal administration group and intravenous injection group were （6. 290 ±4-0. 028）, （6. 150 4±0. 021） and （6. 120 4±0. 008） lg cfu/mL, respectively; while no Mycobacterium tuberculosis was detected in control group. The difference between infection group and control group was statistically significant （t = 3. 762, P〈0.01）, while there were no significant differences among infection groups with different infection routes （P〉0.05）. According to the results of gross observations and histological assessment, the pathological changes were observed and red tubercle bacillus was detected by acid-fast staining in the lung tissues of all the mice in infection group. The results of immunohistochemistry showed that the expression levels of TNF-a per unit area were as follows： intravenous injection group （0. 049 X 10^6 ）〈 intranasal administration group （0.759×10^6） 〈 inhalation group （1.042×10^6）, which were statistically different （t = 2. 504, P〈0. 05）. Conclusion Inhalation of bacteria aerosol may be the most efficient method to establish tuberculosis infection mouse model compared to intravenous injection and intranasal administration.