Evaluation of a Mouse Model of Necrotic Granuloma Formation Using C3HeB/FeJ Mice for Testing of Drugs against Mycobacterium tuberculosis
Evaluation of a Mouse Model of Necrotic Granuloma Formation Using C3HeB/FeJ Mice for Testing of Drugs against Mycobacterium tuberculosis
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DOI：
10.1128/aac.00217-12
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发表时间：
2012-06-01
影响因子：
4.9
通讯作者：
Lenaerts, Anne J.
中科院分区：
文献类型：
--
作者：
Driver, Emily R.;Ryan, Gavin J.;Lenaerts, Anne J.
结核分枝杆菌的持续存在对人类结核病的有效治疗仍然是一个重大挑战。在感染结核分枝杆菌后发生坏死性肺损害的动物中，存在耐药杆菌，并持续存在于坏死灶内的细胞外微环境中。在这项研究中，我们检测了C3HeB/FEJ(Kramnik)小鼠发生液化坏死性损害的药物治疗效果，并与气雾剂攻击后出现非坏死性损害的BALB/c小鼠进行了比较。为此，Kramnik和BALB/c小鼠被结核分枝杆菌气雾剂感染，并使用不同作用模式的药物进行7-8周的单一治疗。药物治疗的疗效通过细菌载量计数来量化。用不同的染色技术显示疾病的进展和病变内细菌的位置和分布。在感染的晚期，Kramnik小鼠出现纤维包裹的肺病变，中央液化坏死区含有丰富的细胞外细菌，而BALB/c小鼠形成非坏死性病变，主要是细胞内细菌。对Kramnik小鼠的坏死灶进行匹莫硝唑染色，发现有缺氧的迹象。Kramnik小鼠对药物治疗的耐受性明显更高，特别是对吡嗪酰胺。甲硝唑在两种模型中均无杀菌活性。与BALB/c小鼠相比，从Kramnik小鼠中分离到的耐药克隆数量显著增加。这些结果表明，Kramnik小鼠模型将是测试抗结核药物，特别是抗坏死灶内持续存在的杆菌的有价值的模型。
Persistence of Mycobacterium tuberculosis remains a significant challenge for the effective treatment of tuberculosis in humans. In animals that develop necrotic lung lesions following infection with M. tuberculosis, drug-tolerant bacilli are present and persist in an extracellular microenvironment within the necrotic cores. In this study, we examined the efficacy of drug treatment in C3HeB/FeJ (Kramnik) mice that develop lesions with liquefactive necrosis, in comparison to BALB/c mice that develop nonnecrotic lesions following aerosol challenge. To accomplish this, Kramnik and BALB/c mice were infected by aerosol with M. tuberculosis and treated for 7 to 8 weeks with monotherapy using drugs with different modes of action. The efficacy of drug therapy was quantified by enumeration of bacterial load. The progression of disease and location and distribution of bacilli within lesions were visualized using various staining techniques. In the late stages of infection, Kramnik mice developed fibrous encapsulated lung lesions with central liquefactive necrosis containing abundant extracellular bacilli, whereas BALB/c mice formed nonnecrotic lesions with primarily intracellular bacilli. Necrotic lesions in Kramnik mice showed evidence of hypoxia by pimonidazole staining. Kramnik mice were significantly more refractory to drug therapy, especially for pyrazinamide. Metronidazole showed no bactericidal activity in either model. There were significantly higher numbers of drug-resistant colonies isolated from the Kramnik mice compared to BALB/c mice. These results suggest that the Kramnik mouse model will be a valuable model to test antituberculosis drugs, especially against bacilli that persist within necrotic lesions.