钙蛋白酶通过调控蛋白激酶B参与肺纤维化的形成

Calpain Promotes Pulmonary Fibrosis Through Activation of Protein Kinase B

目的：探讨钙蛋白酶（calpain）在博来霉素诱导的肺纤维化中的作用及其与蛋白激酶B（PKB）的关系。方法：40只雄性C57BL/6小鼠随机分为生理盐水对照组（NS组）、博来霉素处理组（BLM组）、二甲基亚砜对照组（BLM＋DMSO组）、钙蛋白酶抑制剂组（BLM＋Calpeptin组）,各组小鼠予以相应处理后于第28天行Micro-CT以及HE染色检测肺组织纤维化程度,并且通过Western Blot法测定各组小鼠肺组织中calpain-1、calpain-2的表达和PKB的磷酸化水平。结果：（1）与NS组相比,BLM组小鼠肺组织中可见到明显的纤维化改变,纤维化评分高（P〈0.01）,Calpeptin干预后纤维化程度减轻,纤维化评分降低（P〈0.01）。（2）BLM组小鼠肺组织中calpain-1、calpain-2蛋白的表达以及PKB的磷酸化水平均较NS组升高（P〈0.01）,Calpeptin干预后上述蛋白水平明显下调（P〈0.01）。结论：钙蛋白酶通过调控PKB参与博来霉素诱导的肺间质纤维化。

Objective：To investigate the role of calpain in bleomycin-induced pulmonary fibrosis and the relationship between calpain and protein kinase B（PKB）.Methods：A total of 40 C57 BL/6 mice were randomly assigned to four groups：normal group（NS group）,bleomycin-induced group（BLM group）,DMSO control group（DMSO group）,Calpeptin-treated group（BLM＋Calpeptin group）.After giving the corresponding processing on day 28,Micro-CT and HE staining were used for analysis of lung fibrosis,while the expression of calpain-1,calpain-2,phosphorylated PKB（p-PKB）were evaluated by Western Blot.Results：BLM group showed fibrotic changes and higher fibrosis scores compare with NS group（P〈0.01）,while such fibrotic changes were effectively inhibited in BLM＋Calpeptin group,and calpeptin also declined the fibrosis scores（P〈0.01）.Additionally,the expression of calpain-1,calpain-2 and p-PKB were markedly increased in BLM group（P〈0.01）,while they were all decreased in BLM＋Calpeptin group（P〈0.01）.Conclusion：Calpain could promote BLM-induced pulmonary fibrosis through activation of protein kinase B.