Effect of crizotinib on TGF-β1 signaling pathway in acute radiation-induced lung injury in mice / 中华放射医学与防护杂志

ABSTRACT

Objective:To study the effect of crizotinib on acute radiation-induced lung injury in mice and its possible mechanism.Methods:A total of 72 mice were randomly divided into 4 groups by the random number table method: healthy control group (NC group, n=12), crizotinib-only group (CRZ group, n=12), radiotherapy-only group (RT group, n=24), and radiotherapy pluscrizotinib group (RT+ CRZ group, n=24). The whole lungs were exposed to a single dose of 12 Gy X-rays. Lung tissue and bronchoalveolar lavage fluid (BALF) were obtained at 1, 2, 4, and 8 weeks after radiotherapy. The total number of nucleated cells was counted under a light microscope, and the total protein content of BALF was detected by bicinchoninic acid (BCA) protein assay. The pathological changes of lung tissue were observed by HE staining and MASSON staining. The expressions of TGF-β1 and ICAM-1 mRNA in lung tissue were detected by real-time quantitative polymerase chain reaction (qPCR), the locations and expressions of MPO and ICAM-1 proteins were observed by immunohistochemical staining, and the expressions of TGF-β1, Smad3, p-Smad3 and ICAM-1 proteins in lung tissue were detected by Western blot. Results:At different time points after irradiation, the pathological manifestations such as inflammation and exudation of lung tissue in the RT+ CRZ group were significantly increased, and the total number of cells and protein content in BALF was higher than that of the other three groups, compared with RT group, the difference was statistically significant at 4 week ( t=-5.031, -2.814, P<0.05). Compared with RT group, the expressions of ICAM-1 and TGF-β1 mRNA in lung tissue of the RT+ CRZ group were significantly increased, while the expression of TGF-β1 increased significantly at 1, 4 and 8 weeks after irradiation ( t=-2.687, -7.032, -5.221, P<0.05), and the expression of ICAM-1 increased significantly at 2 and 4 weeks after irradiation ( t=-4.819, -6.057, P<0.05). The expressions of these two gradually increased from 1 to 4 weeks and peaked in 4 weeks, then decreased at 8 weeks. At the same time, the trend of the expression of MPO mRNA was consistent with ICAM-1 and TGF-β1. At 4 week, there was no difference in the expression of Smad3 protein in these four groups ( P>0.05). The expressions of TGF-β1, p-Smad3, ICAM-1 and p-Smad3/Smad3 proteins of the RT+ CRZ group were all higher than those of the other three groups ( F=14.74, 10.03, 35.29, 22.94, P<0.05). Conclusions:Crizotinib combined with radiotherapy can aggravate acute radiation-induced lung injury, which may due to the increase of ICAM-1 expression by up-regulating the TGF-β1 signaling pathway.