骨桥蛋白在急性肺损伤后肺纤维化大鼠肺组织中的表达及作用

Expression and effect of osteopontin on the pulmonary fibrosis after acute lung injury induced by lipopolysaccharide in rats

目的：观察骨桥蛋白（ OPN）在脂多糖（ LPS）诱导的急性肺损伤（ ALI）后肺纤维化大鼠肺组织中的表达及作用。方法120只SD大鼠随机分为对照组、模型组、干预组，每组40只。对照组第0、1、2天腹腔注射生理盐水，模型组和干预组注入等量LPS，5 min后干预组再注入抗OPN抗体，而模型组和对照组用生理盐水代替，于24 h、7 d、14 d、28 d处死3组大鼠各10只。行HE及Masson染色观察肺泡炎及肺纤维化改变；免疫组化测定肺组织转化生长因子－β1（ TGF－β1）的表达；检测肺组织匀浆中OPN蛋白水平、羟脯氨酸含量及Ⅰ、Ⅲ型胶原mRNA的表达。结果模型组第24 h首先出现肺纤维化改变，第28天最明显；同一时间点，模型组肺纤维化评分、TGF－β1的表达、OPN水平、羟脯氨酸含量及Ⅰ、Ⅲ型胶原mRNA表达均显著高于对照组，而干预组上述指标较模型组均显著降低。结论 OPN在LPS诱导的ALI后肺纤维化大鼠肺组织中高表达，能加重LPS诱导的ALI后肺纤维化，机制可能与OPN促进TGF－β1及Ⅰ、Ⅲ型胶原的表达有关。

Objective To observe the expression and effect of osteopontin （ OPN） on the pulmonary fibrosis after acute lung injury （ ALI） induced by lipopolysaccharide （ LPS） in rats.Methods One hundred and twenty SD rats were randomly divided into control group , model group and treatment group, with 40 rats in each group .Rats were injected with normal saline in control group , LPS solution in model group and treatment group .Five minutes later , rats in treatment group were injected with anti -OPN antibody , while rats in control group and model group were injected with normal saline in the same way.Ten rats in each group were sacrificed at the 24 th,7 th,14 th and 28 th day, respectively.Alveolitis and pulmonary fibrosis were assessed by HE and Masson staining .The expression of TGF -β1 was measured by immunohistochemistry .OPN protein levels ,hydroxyproline content , typeⅠandⅢcollagen mRNA were determined .Results The changes of pulmonary fibrosis first appeared in model group at 24 h, but it was most obvious at the 28th day.Compared with control group , the degree of pulmonary fibrosis,the expression of TGF -β1 , OPN levels, hydroxyproline content and type Ⅰ and Ⅲ collagen mRNA were increased significantly in model group at the same time point , while all of these changes were attenuated significantly in treatment group compared with model group . Conclusion The expression of OPN in lung tissue was increased significantly in the pulmonary fibrosis after ALI induced by LPS.OPN can aggravate the degree of pulmonary fibrosis caused by ALI , which might be related to promote the expression of TGF-β1 and type ⅠandⅢcollagen .