Toll-like Receptor 5 Agonism Protects Mice from Radiation Pneumonitis and Pulmonary Fibrosis

Radiation pneumonitis and pulmonary fibrosis are the main complications with radiotherapy for thoracicneoplasms, directly limiting the efficient dose in clinical application and currently there are few medicines thateffectively function as radioprotectants. However, a TLR5 agonist, CBLB502, was confirmed to have protectiveefficacy against hematopoietic and gastrointestinal radiation syndromes in mice and primates. This study pointsto a new direction for protection against thoracic radiation-induced pulmonary syndromes and skin injury byCBLB502. We utilized the TUNEL assay, pathological analysis and immunohistochemistry to obtain evidence thatCBLB502 could alleviate the occurrence of radiation pneumonitis and pulmonary fibrosis as well as radiationinducedskin injury. It may thus play a promising role in facilitating clinical radiotherapy of thoracic neoplasms.