强力霉素对实验性小鼠肺纤维化的抑制作用

Inhibition of pulmonary fibrosis by doxycycline: an experiment with mice

目的探讨具有Ⅳ型胶原酶抑制活性的抗感染抗生素强力霉素对博来霉素诱发的小鼠肺纤维化的抑制作用。方法采用明胶酶谱法测定强力霉素对HT-1080细胞分泌Ⅳ型胶原酶及酶活性的影响,采用气管内灌注博来霉素的方法复制小鼠肺纤维化模型,采用生化方法测定肺组织中羟脯氨酸含量,采用病理组织学结合图像分析方法观察评价小鼠肺组织纤维化程度。结果强力霉素在体外能抑制HT-1080细胞分泌IV型胶原酶,0·1mg/ml、0·05mg/ml强力霉素能显著抑制HT-1080细胞MMP-9和MMP-2的分泌。强力霉素对于已外泌的Ⅳ型胶原酶的活性也有抑制作用。生化检测结果表明:100mg/kg的强力霉素可以显著减少博来霉素诱导的小鼠肺部羟脯氨酸的含量,在实验第21天检测其含量是博来霉素模型组的35%,两者相比有显著性差异(P<0·01)。病理组织学观察和图像分析结果进一步表明:强力霉素治疗组在小鼠左肺叶发生纤维化的面积比率、肺泡间隔所占面积比率和有核细胞计数都明显少于博来霉素模型组;100mg/kg强力霉素组与3mg/kg的醋酸泼尼松龙治疗组治疗效果相近。结论强力霉素可抑制Ⅳ型胶原酶的活性,对博来霉素诱导的小鼠肺纤维化有抑制作用。

Objective To investigate the effect of doxycycline, an antimicrobial antibiotic inhibiting type Ⅳ collagenase, on the development of pulmonary fibrosis induced by bleomycin （ BLM ） in mice. Methods Gelatin zymography assay was used to detect the secretion of 72 000 and 92 000 type Ⅳ collagenase in HT-1080 cells and the activity of these enzymes in vitro. Experimental pulmonary fibrosis was induced by intra-tracheal administration of BLM in anesthetized mice. Total lung collagen content was determined by hydroxyproline assay. The histopathological changes of pulmonary fibrosis were evaluated by image analysis. Results The secretion of 72 000 and 92 000 type Ⅳ collagenase in HT-1080 cell was markedly inhibited by doxycycline at concentrations of 0. 1 mg/ml and 0.05 mg/ml. The activity of type Ⅳ collagenase in vitro was also suppressed by doxycycline. The hydroxyproline level in the lung was decreased in mice treated with doxycycline at the dose of 100 mg/kg, down to 34. 7% of that of the BLM model group. As shown by image analysis, the extensiveness of fibotic lesions, the thickness of interalveolar sepia, and the accumulation of nucleated cells were decreased in doxycycline treated group in comparison with BLM model group. Conclusion This study provides evidence that doxycycline, shows inhibitory effect on BLM induced pulmonary fibrosis.