白细胞介素-1β在石英致小鼠肺纤维化中的作用

The role of interleukin-1β on the pulmonary fibrosis in mice exposed to crystalline silica

目的研究白细胞介素（IL）-1β在石英导致矽肺肺纤维化过程中的作用。方法将96只雄性C57BL／6小鼠随机分为空白对照组、PBS组、石英＋IL．1B抗体组、石英组，每组24只。空白对照组不予以任何处理；PBS组-次性肺灌注无菌PBS50p．1；石英＋IL-1β抗体组-次性肺灌注中国标准石英悬液10μl（250mg／m1）＋仓鼠抗小鼠IL-1β抗体（anti—IL-1pmAb）40¨l（1β∥μ1）；石英组-次性肺灌注中国标准石英悬液10μl（250mg／m1）＋仓鼠IgG40μl（μg／μ1）。在每组小鼠随机各取8只分别在相应处理后7、28、84d处死，收集肺泡灌洗液（BALF）并对BALF中各类炎性细胞进行分类计数；测定BALF中IL-1p、肿瘤坏死因子-a（TNF-a）、单核细胞趋化蛋白-1（MCP-1）、干扰素--y（IFN-1）及IL-4含量；对肺组织转化生长因子-[3（TGF—B）、I型胶原及纤维黏连素mRNA水平进行荧光实时PCR检测，并对肺组织切片进行病理形态学观察。结果石英＋IL-1β抗体组小鼠肺部胶原沉积程度比同期石英组小鼠明显减轻。石英组和石英＋IL-1β抗体组小鼠BALF中炎性细胞数及IL-1β、TNF—d、MCP-1浓度均高于同期空白对照组或PBS组，差异有统计学意义（P〈0．01）。石英＋IL-1β抗体组小鼠BALF中炎性细胞数及IL-1p、TNF．OL、MCP-1浓度均低于同期石英组，差异有统计学意义（p〈O．05，P〈0．01）。石英组和石英＋ILlp抗体组小鼠肺组织中TGF—B、纤维黏连素mRNA水平在灌肺后28、84d均高于空白对照组或PBS组，差异有统计学意义（P〈0．01）。石英＋IL．1p抗体组小鼠肺组织中TGF—p、I型胶原和纤维黏连素mRNA水平在染尘后28、84d均低于石英组，差异有统计学意义（P〈0．05或P〈0．01）。石英组和石英＋IL-1β抗体组小鼠肺部IFN-7／IL-4比值均低于同期空白对照组或PBS组，差异有统计学意义（P〈0．01）。石英＋IL-1β抗体组小鼠肺部IFN-／IL-4比值均高于同期石英组，差异有统计学意义（P〈0．05或P〈0．01）。结论矽肺发病过程中，IL-1p可能通过促进致纤维化因子TGF—p的表达及调节Thl／Th2平衡向Th2转化而促进肺纤维化形成。

Objective This study was designed to evaluate the role of interleukin （IL）-1β in the development of fibrosis in mice exposed to silica. Methods The total of 96 Male C57BL/6 mice were divided into four groups. （1） blank control group, （2） PBS group in which mice were instilled with PBS only, （3） silica＋IL-1β mAb group in which mice were instilled with 2.5 mg silica dust and 40 μg anti-IL-1β mAb, （4） silica group in which mice were instilled with 2.5 mg silica dust and 40 μg IgG. The final volume of suspension or PBS instilled into the mouse was 50μl. At 7, 28 and 84 days after treatment, 8 mice were sacrificed in each group. Then BALF was collected for the count of inflammatory ceils and cytokines determination. The lung tissues were collected for the detecting of mRNA levels of fibrogenic molecules. Results The collagen deposition induced by silica in the lung tissues was partly inhibited by anti-IL-1β. A intensely pulmonary cytokines such as IL-1β,TNF-a,MCP-1 were induced by crystalline silica exposure, and partly inhibited by anti-IL-1β. The levels of TGF-1β and fibronectin in silica exposed mice were significantly elevated than those in control mice at days 28 and 84 after treatment （P〈0.01）. And the mRNA levels of TGF-1β, collagen I and fibronectinwere significantly decreased in silica＋IL-1β mAb group when compared with those in silica group at days 7, 28 and 84 （P〈O.O1）. There was a significant decrease of the ratios of IFN-y/IL-4 in both silica＋anti-IL-I [3 mAb and silica groups when compared with those in control mice at the above three time points （P〈0.01）. However, the IFN-y/IL-4 ratios in silica＋anti-IL-1 [5 group were significantly higher than those in silica group at 7, 28 and 84 days （P〈0.05 or P〈0.01 ）. Conclusion IL-1β may promote the pulmonary fibrosis in mice exposed to silica.