Radiation pneumonitis is a common complication of thoracic irradiation for lung cancer patients. The healthy gut microbiota plays an important role in the local mucosal defense process as well as pulmonary immunomodulation of the host. However, the effect of the intestinal microbiota on radiation pneumonitis is not well understood. Here we studied how the intestinal microbiota affected the host response to radiation pneumonitis. C57BL/6 mice were administered antibiotics to induce disequilibrium in the gut microbiota, and subsequently irradiated. We found that the intestinal microbiota served as a protective mediator against radiation pneumonitis, as indicated by decreased body weight and increased mortality in antibiotic-treated mice. In mice with gut microbiota disequilibrium, more serious pathological lung damage was observed at two and four weeks postirradiation. Fecal microbiota transplantation into irradiated mice led to improvement from radiation-induced inflammation two weeks postirradiation. High-throughput sequencing of murine feces displayed conversion of flora diversity, bacterial composition and community structure in the absence of normal intestinal flora. We filtered the potentially important species among the gut microbiota and considered that the tissue-type plasminogen activator might be involved in the inflammatory process. This study reveals that the gut microbiota functions as a protective regulator against radiation pneumonitis. Additionally, fecal microbiota transplantation was shown to alleviate lung injury in the irradiated model. The protective role of the healthy gut microbiota and the utilization of the gut-lung axis show potential for innovative therapeutic strategies in radiation-induced lung injury.

中文翻译：

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肠道菌群起辐射性肺炎的保护性调节作用。

放射性肺炎是肺癌患者胸腔照射的常见并发症。健康的肠道菌群在宿主的局部粘膜防御过程以及肺部免疫调节中起着重要作用。但是，肠微生物群对放射性肺炎的作用尚不十分清楚。在这里，我们研究了肠道菌群如何影响宿主对放射性肺炎的反应。给C57BL / 6小鼠施用抗生素以诱导肠道菌群失衡，然后进行辐照。我们发现，肠道菌群可作为抵抗放射性肺炎的保护性介质，如体重减轻和抗生素治疗小鼠死亡率增加所表明。在肠道菌群失衡的小鼠中，照射后两周和四周观察到更严重的病理性肺损伤。粪便微生物群移植到受辐照的小鼠后，辐照后两周可改善辐射诱发的炎症。在没有正常肠道菌群的情况下，鼠粪的高通量测序显示出菌群多样性，细菌组成和群落结构的转化。我们过滤了肠道菌群中潜在的重要物种，并认为组织型纤溶酶原激活物可能与炎症过程有关。这项研究表明，肠道菌群可作为针对放射性肺炎的保护性调节剂。另外，在照射的模型中，粪便微生物群移植被证明减轻了肺损伤。