目的：评估C-Raf抑制剂GW5074对高剂量小范围放射线诱导的肺泡上皮细胞间质转化的影响。方法：观察GW5074处理对高剂量放射线引起的细胞形态学改变；细胞经GW5074处理或转染sh-Twist1后，通过Western blot 检测C-Raf、 p-C-Raf、Twist1、α-平滑肌肌动蛋白（alpha-smooth muscle actin，α-SMA）和E-钙黏蛋白（E-cadherin）的表达量。应用高剂量小范围放射线照射小鼠后，通过对损伤组织的HE染色及免疫荧光染色观察上皮间质转化现象。结果：在细胞实验中，GW5074可有效减轻高剂量放射线引起的细胞形态学变化。高剂量放射线可使C-Raf蛋白激活，且在照射后48 h的作用最强。照射前应用GW5074和sh-Twist1预处理，能使Twist1和α-SMA的表达量减少而E-cadherin的表达量增加，sh-Twist1组p-C-Raf的表达量与照射组无明显差异。在动物实验中，GW5074可有效减轻放射线造成肺损伤的程度，明显减少α-SMA并增强E-cadherin的表达。结论：GW5074可能通过抑制C-Raf/Twist1信号通路有效减轻高剂量小范围放射线诱导的肺泡上皮细胞间质转化。
Abstract:
Objective：To assess the effect of GW5074 on the alveolar epithelial cell mesenchymal transition caused by high-dose small-volume radiation. Methods：In cell experiments，the morphological changes of cells before and after GW5074 treatment were observed. The expressions of C-Raf，p-C-Raf，Twist1，α-SMA and E-cadherin were detected by Western blot. After high-dose small-volume irradiation on mouse，the epithelial to mesenchymal transition of the injured tissues was observed by means of HE staining and immunofluorescence staining. Results：GW5074 alleviated effectively the morphological changes caused by high-dose irradiation. High-dose irradiation may activate C-Raf protein with the strongest effect at 48 hours after the irradiation. Pre-treatment by GW5074 and sh-Twist1 before irradiation can reduce the expressions of both Twist1 and α-SMA while increasing the expression of E-cadherin. The expression of p-C-Raf in the sh-Twist1 group was not significantly different from that in the irradiated group. Conclusion：By inhibiting the C-Raf/Twist1 signal path，GW5074 may effectively attenuate the alveolar epithelial cell mesenchymal transition caused by high-dose small-volume irradiation.
