Ophiopogon japonicus inhibits radiation-induced pulmonary inflammation in mice

Background: Radiation-induced lung injury, including the acute pulmonary inflammation and chronic pulmonary fibrosis remains the major complication of thoracic radiotherapy. Methods: In this study, we assessed the effects of Ophiopogon japonicus (O. japonicas) in inhibiting the radiation-induced pulmonary inflammation through an acute lung injury mouse model using C57BL/6 mice that received 18 Gy irradiation to the thoracic region. Starting at 4 days before radiation, mice were treated with O. japonicus or dexamethasone combined with cephalexin or vehicle daily for 14 days. Results: Exposure to radiation resulted in pulmonary inflammation in mice, but treatment with O. japonicus or dexamethasone-cephalexin could both significantly reduce radiation-induced pulmonary inflammation through inhibition of IL-6, TNF-alpha, TGF-beta 1, hydroxyproline, MDA, MMP-2 and TIMP-2 in plasma or lung tissue. In addition, through analyzing tissue damage, cytokines and inflammation-related protein at 12 weeks after irradiation, we found that the protective effect of O. japonicus was more enduring than dexamethasone-cephalexin. Conclusions: As radiation-induced lung injury is a major obstacle in thoracic radiotherapies and seriously affect the quality of patients' life. Application of O. japonicus may be a novel strategy to manage radiation-induced pulmonary inflammation.