大鼠肺纤维化形成中肺内肥大细胞结缔组织生长因子的表达

The expression of connective tissue growth factor in mast cells in the development of pulmonary fibrosis

目的:观察博莱霉素(BLM)诱导肺纤维化形成中肺肥大细胞(MCs)是否表达结缔组织生长因子(CTGF)。方法:32只雄性SD大鼠,随机分为博莱霉素(BLM)组和对照(Control)组(n=16)。BLM组为气管内一次性滴注BLM(5 mg/kg);Control组为气管内滴注与BLM等容量的生理盐水(NS)。各组分别在气管滴注后第14天和第28天处死大鼠,取肺组织样本。用氯胺-T法检测肺组织羟脯氨酸含量以判断肺纤维化程度;用甲苯胺蓝染色显示肺组织切片中的MCs;免疫组化染色显示肺CTGF的表达和分布。结果:①与对照大鼠比,气管内滴注BLM后第28天大鼠的肺羟脯氨酸含量明显增高(P<0.01)。②与对照大鼠比,气管内滴注BLM后第14天和第28天大鼠肺内MCs数明显增多(均P<0.01),肺内CTGF表达上调(均P<0.01)。③对照大鼠肺内未见CTGF免疫阳性的MCs;而气管内滴注BLM后第14天和第28天大鼠肺内病灶区中有CTGF免疫阳性的MCs。结论:肺纤维化形成中肺MCs表达CTGF,这可能是MCs促进肺纤维化的作用机制之一。

Objective： To investigate whether connective tissue growth factor （CTGF） is expressed in mast cells （MCs） in lung in the development of bleomycin （BLM）-induced pulmonary fibrosis. Methods： Thirty-two male SD rats were randomly divided into 2 groups： BLM group and control group （ n = 16）. The rats in BLM group were received single intratracheal instillation of BLM （5 mg/kg ）, and the rats in control group received equal volume of 0.9% normal saline（NS） to BLM. The rats in each group were sacrificed for lung tissue sampling on day 14 and day 28 after intratracheal instillation respectively. As the index of the severity of pulmonary fibrosis, the content of hydroxyproline in lungs was analyzed by chloramine T method. Mast ceils and CTGF expression in lungs were examined by toluidine blue stain and immunohistochemical assay respectively. Results： （1） On day 28 after intratracheal instillation of BLM, the content of hydroxyproline in lungs of rats was higher than that of cuntrol rats （ P 〈 0.01）. （2） Compared to control rats, the rats on day 14 and day 28 after instillation of BLM showed increased number of mast cells （Both P 〈 0.01） and up-regulated CTGF expression （Both P 〈 0.01）. （3） No CTGF immuno-positive MCs were seen in the lungs of control rats whereas CTGF immuno-positive MCs were observed in the pathological areas in lungs of rats on day 14 and day 28 after BLM. Conclusion： CTGF is expressed in MCs in lungs in the development of ptdmonary fibrosis, which might be one of the mechanisms underling promoting effect of MCs on fibrosis in lung.