博莱霉素诱导肺纤维化小鼠模型的建立及特征

Establishment and verification of the mouse model of pulmonary fibrosis induced by bleomycin

目的探讨博莱霉素气管灌注诱导肺纤维化小鼠模型在不同时期分子生物学及组织病理学的改变。方法 6～8周龄C57BL/6小鼠60只,30只为正常对照组,30只以博莱霉素2.5 mg/kg单次气管灌注建立小鼠肺纤维化模型(模型组),以肺组织病理学形态及基因表达水平为指标,判断模型小鼠肺纤维化发展阶段。结果正常对照组小鼠的肺组织无明显病理改变,模型组小鼠肺部有不同程度的肺泡结构破坏、炎性细胞浸润以及大量以胶原为主的细胞外基质沉积。基因表达检测结果显示:模型组灌注博莱霉素1～2周,小鼠肺组织白介素(IL)-4、IL-13较正常对照组升高,而3～5周模型组与正常对照组无差异(P>0.05)。模型组肺组织中胶原基因Colla2、Cola13、结缔组织生长因子(CTGF)、转化生长因子-β_1(TGF-β_1)均较正常对照组有不同程度的升高,与组织病理学改变一致。结论博莱霉素2.5 mg/kg单次气管灌注可成功建立肺纤维化小鼠模型;博莱霉素灌注早期以肺部炎性浸润为主,第3周时肺纤维化达到高峰,第5周开始纤维化有所缓解。

Objective To investigate the change of molecular biology and histopalhology in the different periods of pulmonary fibrosis model induced by instillation of bleomycin（BLM）.Methods Lung fibrosis was induced by a single intratracheal instillation of bleomycin（2.5 mg/kg） in C57BL/6 female mice of 6 to 8 weeks.To judge the development of pulmonary fibrosis of the mouse model,lung samples were collected from these mice to measure the gene expression,collagen content and histopathological status.Results Mice in the normal control group shown no significant changes in lung tissues.But infiltration of the lymphocytes into the mice lung interstitial,thickening of the alveolar septa,collapse of the alveolar spaces, and excessive deposition of collagen were observed in the bleomycin treated mice lungs.The mRNA levels of IL-4,IL-13 were examined to assess the inflammation status.The mRNA level of IL4,IL-13 was enhanced by bleomycin.Correspondingly, the expression levels of Colla2,Col3a1,connective tissue growth factor（CTGF） and transforming growth factor-β_1（TGF-β_1） were higher than the normal group.The results are concordant with that of pathological findings.Conclusion Pulmonary fibrosis model could successfully establish by a single intratracheal instillation of bleomycin.At the early stage after the administration of BLM,the inflammatory response was acute and this response last about one week,and then followed by fibrogenic changes,and in the third week,pulmonary fibrosis was most significant,but the fibrosis has been eased by the fifth week.