Pulmonary surfactant vesicles prevent ionizing radiation-induced lung injury by pulmonary delivery

Radiotherapy is one major treatment of chest tumors such as lung, esophageal and breast cancers and ionizing radiation-induced lung injury (RILI) is the common adverse event, leading to pneumonitis and pulmonary fibrosis. High-dose corticosteroids are usually used for the treatment of RILI though the side effects are obvious. Here, we prepared pulmonary surfactant vesicles (PSVs) containing surface proteins. Pulmonary surfactant showed lower surface pressures than pure dipalmitoylphosphatidylcholine (DPPC) in a Langmuir monolayer experiment, indicating the former higher surface activity. PSVs, DPPC vesicles (DVs), and dexamethasone (DXMS) suspensions were separately intratracheally administered to the mice 1 h prior to 20-Gy 60Co gamma radiation on their chests. The mice in the PSV group had good pulmonary functions with a higher peak expiratory flow and expiratory flow at 50 % tidal volume than those in the DXMS group. Moreover, the physical activity of the mice in the PSV group was stronger than that in the DV group. PSVs had remarkable lung protection from ionizing radiation by supplementing lung surfactants, decreasing alveolar-capillary barrier permeability, downregulating proinflammatory cytokines, and attenuating cell apoptosis. PSVs hold promise for the protection of the lung from ionizing radiation.