烟曲霉菌感染小鼠肺组织中NOD1信号通路的激活

Activation of NOD1 signal pathway in the lungs of mice infected with Aspergillus fumigatus

目的研究天然免疫NOD1信号通路在烟曲霉菌感染小鼠肺组织中是否得以激活。方法小鼠分为正常对照组和感染组,感染组小鼠经鼻滴入烟曲霉菌孢子24 h、48 h、72 h后分别处死,碾碎肺组织平板培养以检测其肺组织烟曲霉菌负荷,观察肺组织病理学改变,RT-PCR检测NOD1及RIP2 mRNA表达量、Western Blot检测胞核NF-κBp65和胞浆TNF-α在小鼠肺组织中的含量。结果①感染组小鼠肺组织48 h时Af负荷达最高且可见严重的充血和出血,有大量的炎症细胞浸润,72 h时Af负荷迅速下降且未见菌丝形成,仅见轻微的充血、出血和炎症反应;正常组烟曲霉菌培养阴性且肺组织结构正常;②RT-PCR及Western Blot结果显示:感染组小鼠肺组织各时相点NOD1 mRNA、RIP2 mRNA、NF-κBp65和TNF-α的表达量均明显高于正常对照组(P<0.05),前三者均在48 h表达最高,TNF-α在72 h表达最高(P<0.05)。结论NOD1信号通路在烟曲霉菌感染的小鼠肺组织中得以活化,其介导的天然免疫对抗烟曲霉菌感染和保护小鼠肺组织起了一定的作用。

In this study,we aimed to explore whether NOD1 signal pathway was activated in the lungs of mice infected with Aspergillus fumigatus（Af）.The mice were divided into the normal group and the infected group.The infected mice were sacrificed at time points of 24,48,and 72 h post challenge of Af conidia,while Af burden and pulmonary histopathology were observed at different time points.In infected group,Af burden reached a peak at 48 h and decreased remarkably at 72 h,while severe hyperemia,bleeding and inflammatory cells infiltration were found at 48 h,which were markedly lessened at 72h.But the Af colony was not found and lung tissue structure was normal in normal group.RT-PCR and Western blot showed NOD1 mRNA and RIP2 mRNA expression levels,as well as NF-κBp65 and TNF-αprotein amount were remarkably higher in infected group than those in normal group（P0.05）.The highest levels of NOD1 mRNA,RIP2 mRNA,and NF-κBp65 were found at 48 h,while the highest TNF-αlevel was appeared at 72 h （P0.05）.Above results demonstrate that NOD1 signal pathway do activated by Af infection in mouse lungs and the innate immunity mediated by NOD1 signal pathway plays a partial role in clearing the fungus and protecting the lung from injury.