Effect of Yangyinqingfei decoction on radiation-induced lung injury via downregulation of MMP12 and TIMP-1 expression

The aim of this study was to evaluate the effect and underlying mechanism of Yangyinqingfei decoction on radiation-induced lung injury in rats. Wistar rats (n=75) were randomly divided into five experimental groups (A-E). Rats in two of the groups were administered saline solution, whereas rats in the remaining three groups were administered different doses of Yangyinqingfei decoction. After one week, the rats were irradiated with a single dose of 25 Gy to their right hemi-thoraxes by a Co-60 gamma-ray, with the exception of the control group, which underwent sham irradiation. The effect of Yangyinqingfei decoction was assessed one, two and four weeks post-irradiation according to the pathological changes and the right lung index (wet weight of right lung/body weight x100%). Expression levels of matrix metalloproteinase-12 (MMP-12) and tissue inhibitors of metalloproteinases-1 (TIMP-1) in lung tissue were determined using the reverse transcription-polymerase chain reaction and western blot analysis. Pretreatment with Yangyinqingfei resulted in a significant dose-dependent resistance to radiation-induced body weight loss. The expression of MMP-12 and TIMP-1 increased following irradiation. However, the levels of MMP-12 and TIMP-1 in groups receiving Yangyinqingfei were lower four weeks after irradiation compared with those in rats administered saline. Cumulatively, these results suggest that Yangyinqingfei has a protective effect on radiation-induced lung injury in rats, possibly by downregulating MMP-12 and TIMP-1 expression.