β2-微球蛋白在肺气肿发病过程中的作用

The role of β2-microglobulin in pathogenesis of emphysema

目的探讨β2-微球蛋白(β2-microglobulin,β2m)通过巨噬细胞在肺气肿发病过程中的可能作用。方法小鼠分别烟雾暴露8、16、24周建立肺气肿模型,有创小鼠肺功能仪测定肺功能参数;收集肺泡灌洗液(bronchoalveolar lavage fluid, BALF)进行细胞计数;取肺组织进行苏木精-伊红(hematoxylin-eosin, HE)染色、免疫组织化学染色和免疫荧光共染,分析肺泡结构破坏、β2m表达及其靶细胞情况。佛波酯(phorbol 12-myristate 13-acetate, PMA)体外诱导人单核细胞系THP-1分化为巨噬细胞,以不同质量浓度的人重组β2m刺激48 h,ELISA检测细胞培养上清中炎症因子的改变。结果与对照组小鼠相比,烟雾暴露所致肺气肿模型组小鼠肺泡腔明显扩大,肺总量(total lung capacity, TLC)、肺泡弦长(mean linear intercept, Lm)和肺泡破坏指数(destructive index, DI)均明显增加(P<0.05);BALF细胞总数明显增多,以巨噬细胞为主。免疫组织化学染色及免疫荧光共染显示肺气肿组小鼠肺组织β2m表达上调(P<0.05),且可与巨噬细胞共定位。体外用人重组β2m刺激THP-1巨噬细胞可促进炎症因子IL-1β、IL-6、IL-8的产生(P<0.05)。结论上述数据表明β2m可能通过上调巨噬细胞炎症因子产生从而参与肺气肿的发病过程。研究为未来肺气肿的治疗提供了一个新的潜在干预靶点。

Objective The present study aimed to investigate the possible role of β2-microglobulin (β2m),by means of macrophages in the pathogenesis of emphysema.Methods C57BL/6J mice were exposed to cigarette smoke (CS) for 8,16 and 24 weeks to develop a murine model for human emphysema.The respiratory function parameters of each mouse group were assessed using an invasive pulmonary function device.Bronchoalveolar lavage fluid (BALF) was collected in counting cells.HE staining,immunohistochemistry and immunofluorescence were performed in paraffin-embedded sections from tissue of lungs in analysis of destruction of alveolar walls,the expression and target cells of β2m.Human monocyte cell line THP-1 was incubated with Phorbol 12-myristate 13-acetate (PMA) to differentiate into macrophages in vitro and stimulated with different concentrations of human recombinant β2m for 48 h.ELISA detections were employed to measure concentrations of pro-inflammatory cytokines in the supernatants of cell cultures.Results Compared with controls,the alveolar space was significantly enlarged in the mice at 8,16 and 24 weeks after CS exposure.The total lungs capacity (TLC),the mean linear intercept (Lm) and the destructive index (DI) were also significantly elevated (P <0.05).The total number of cells in BALF of the experimental animals increased substantially,and shifted towards an abundant presence of macrophages.Immuno-histochemistry showed that the expression of β2m in lungs tissue was up-regulated in the emphysema groups (P <0.05),which was co-localized with macrophages identified by double immunofluorescence staining.In vitro,human recombinant β2m enhanced the production of pro-inflammatory cytokines IL-1β,IL-6 and IL-8 in THP-1 macrophages (P <0.05).Conclusion These data suggests that β2m may participate in the pathogenesis of emphysema through promoting the production of pro-inflammatory cytokines by macrophages,providing a new target for the treatment of emphysema.