纤维细胞和Thl／Th2型细胞因子在放射性肺损伤中的作用及相关机制

Changes of fibrocytes and related Thl/Th2 cytokines in mice with radiation-induced pulmonaryinjury

目的 观察小鼠经60Co γ射线胸部照射后肺组织中纤维细胞和Th1/Th2型细胞因子变化规律,探究其在放射性肺损伤中的作用及相关机制.方法 小鼠经60Coγ射线单次胸部照射25 Gy,建立肺损伤模型,用HE染色和Masson三联染色观察肺组织病理变化,酶标仪测定Ⅰ型胶原浓度,流式细胞仪测定小鼠肺实质中纤维细胞数目,液相悬浮芯片检测肺泡灌洗液中纤维化相关细胞因子单核细胞趋化蛋白-1（MCP-1）、巨噬细胞炎症/性蛋白-1α（MIP-1α）和Th1/Th2型细胞因子表达.结果 照后14 d至3个月,小鼠体重明显下降（F=7.19、40.62、58.70,P＜0.05）.1个月时小鼠肺组织胶原纤维增生,第3个月时更加明显.照后1～3个月,Ⅰ型胶原浓度明显增加（Z=-2.470、-2.236,P＜0.05）.照射后14 d至3个月,纤维细胞数目增多（Z=-2.19、-2.64、-2.64,P＜0.05）,肺灌洗液中MCP-1（Z=-2.35、-2.37、-2.34,P＜0.05）及MIP-1α（Z=-2.43、-2.35、-2.35,P＜0.05）表达增高.Th1型细胞因子IFN-γ在照后1个月短暂升高（Z=-2.34,P＜0.05）,IL-12在照后3d及7d下降（Z=-2.31、-2.30,P＜0.05）,1个月及3个月升高（Z=-2.32、-2.12,P＜0.05）；Th2型细胞因子IL-4在照后7、14 d及1个月表达升高（Z=-2.31、-2.35、-2.32,P＜0.05）,IL-10在照后3d及1、3个月升高（Z=-2.33、-2.37、-2.34,P＜0.05）.结论 纤维细胞是诱发放射性肺损伤的重要效应细胞,MCP-1及MIP-1α能明显诱导纤维细胞聚集,Th1/Th2可能参与调节这一过程.

Objective To observe the changes of fibrocytes and Thl/Th2 cytokines in the lung of irradiated mice and explore its role in radiation-induced pulmonary injury. Methods The whole thorax of mice were irradiated with single 25 Gy of 40 Co r-rays in order to establish a model of pulmonary injury. The pathologic changes of lung were determined by Masson three-color stain and Hematoxylin and eosin stain. The concentration of collagen I was assayed by mieroplate spectrophotometer. The number of fibrocytes in lung and the levels of MCP-1, MIP-lct and Thl/Th2 eytokines in BAL were measured with flow eytometry and liquid suspension array, respectively. Results Irradiated mice suffered with weight loss from 14 d to 3 month after irradiation （ F = 7.19, 40. 62, 58.70, P 〈 0.05 ）. Pathological evidence demonstrated that the collagen fibers hyperplasia occurred at 1 month and aggravated at 3 month. Concentration of collagen I （Z = - 2. 470, - 2. 236, P 〈 0. 05 ） increased at 1 and 3 month post-irradiation. There were significant increase in the number of fibrocytes （Z = - 2.19, - 2. 64, - 2.64,P 〈 0.05） in pulmonary interstitium and the levels of MCP-1 （Z-- -2.35, -2.37, -2.34, P〈0.05） andMIP-lct （Z= -2.43, -2.35, -2. 35, P 〈0. 05） in BAL from 14 d to 3 month. The levels of IFN-r increased at 1 month （Z = -2.34 P〈0.05） and the expression oflL-12 decreased at3 and7 d （Z= -2.31, -2.30, P〈0.05） while increased at 1 and 3 month （Z= -2.32, -2.12, P 〈0.05）.IL-4 level were up from 7 d to 1 month （Z= -2.31, -2.35, -2.32, P〈0.05）, and 1L-10 level went up on 3 d, at 1 month and 3 month post-irradiation （Z = - 2.33, - 2.37, - 2.34, P 〈 0.05）. Conclusions Fibrocytes are the important target of radiation-induced pulmonary injury. MCP-land MIP-lαlead to fibrocytes recruitment and Thl/Th2 cytokines may be involved in this process.