吉非替尼对博莱霉素致肺纤维化小鼠α平滑肌肌动蛋白的抑制作用

Gefitinib inhibits α-smooth muscle actin expression in mice with bleomycin-induced lung fibrosis

目的观察吉非替尼对博莱霉素诱导肺纤维化小鼠α平滑肌肌动蛋白(α-SMA)表达的影响,探讨EGFR在肺纤维化上皮间质转分化中的作用。方法将30只SPF级雌性BALB/c小鼠分为三组:对照组(气管滴入生理盐水)、纤维化组(气管滴入博莱霉素3mg/kg)、纤维化吉非替尼干预组(气管滴入博莱霉素+吉非替尼灌胃20mg/Kg)。实验第14天杀鼠取肺,肺组织石蜡切片行HE染色与Masson染色;RT-PCR法检测α-SMA的mRNA表达水平;免疫组化检测总EGFR、磷酸化EGFR及α-SMA表达。结果纤维化吉非替尼干预组肺病理损伤较纤维化组减轻,气道上皮下胶原沉积减少,气道上皮及肺间质细胞磷酸化EGFR表达评分下降(P<0.05);同时,肺α-SMA的mRNA表达减少,免疫组化评分也明显降低(P<0.05)。结论吉非替尼抑制博莱霉素诱导小鼠肺纤维化可能与其抑制EGFR活性,下调α-SMA表达有关。

Objective To evaluate the effect of epidermal growth factor receptor tyrosine kinase inhibitor,gefitinib,on the expression of α-smooth muscle actin （α-SMA） in mice with lung firosis induced by bleomycin. Methods Thirty male BALB/c mice were randomly divided into control,bleomycin,and bleomycin plus gefitinib groups. The mice in the control group were subjected to intratracheal administeration of normal saline,those in bleomycin group received bleomycin （3 mg/kg） intratracheally,and those in bleomycin plus gefitinib group received oral gefitnib （20 mg/kgadministering） plus intratracheal bleomycin administartion. All the mice were sacrificed 14 days after the treatments,and the left lung was examined pathologically with HE staining and Masson staining and also immunohistochemically for assay of the total EGFR,phosphorylated EGFR and α-SMA. The right lungs were sampled for RT-PCR to detect the mRNA levels of α-SMA. Results Gefitinib administration lessened lung fibrosis induced by bleomycin and significantly reduced lung collagen accumulation. The phosphorylation of EGFR in the pulmonary mesenchymal cells and epithelial cells and the expression levels of α-SMA mRNA and protein were inhibited by gefitinib treatment in mice with intratracheal administration of bleomycin （P0.05）. Conclusions Geitinib offers protection against lung fibrosis induced by bleomycin in mice probably by inhibiting the downstream signals of EGFR and by downregulating the expression of α-SMA.