9慢性阻塞性肺疾病大鼠膈肌萎缩信号通路与白细胞介素17相关性的研究

目的研究慢性阻塞性肺疾病（COPD）大鼠膈肌萎缩信号通路——泛素-蛋白酶体通路中E2-14K、MAFbx和MuRF-1蛋白表达及核转录因子κB（NF-κB）p50表达情况,以及前炎症因子白细胞介素17（IL-17）在大鼠血清及膈肌中的表达,探讨膈肌萎缩的可能调控机制。方法采用气管内滴入脂多糖＋反复熏香烟法复制COPD大鼠动物模型。Western blot法测定大鼠膈肌内E2-14K、MAFbx、MuRF-1及NF-κB p50表达,ELISA法测定大鼠血清及膈肌中IL-17的表达。结果 Westernblot结果显示COPD大鼠膈肌中E2-14K、MAFbx、MuRF-1及NF-κB p50蛋白的表达均较对照组明显升高（0.96±0.12比0.53±0.09,0.99±0.10比0.53±0.08,0.95±0.08比0.51±0.16,1.11±0.10比0.64±0.50,P均〈0.01）。ELISA结果显示IL-17在血清及膈肌中的表达均升高（P均〈0.01）。NF-κB p50与E2-14K、MAFbx、MuRF-1水平呈显著正相关（r值分别为0.82、0.92、0.86,P均〈0.01）;血清IL-17与中性粒细胞百分比、NF-κB p50、E2-14K、MAFbx、MuRF-1呈显著正相关（r值分别为0.94、0.90、0.85、0.84及0.79,P均〈0.01）;膈肌IL-17与中性粒细胞百分比、NF-κB p50、E2-14K、MAFbx、MuRF-1呈显著正相关（r值分别为0.88、0.90、0.72、0.86及0.80,P均〈0.01）;血清IL-17与膈肌IL-17呈显著正相关（r=0.84,P〈0.01）。结论 COPD大鼠膈肌中泛素-蛋白酶体通路与NF-κB通路表达上调可能是导致膈肌萎缩的主要原因之一,IL-17可能参与了膈肌萎缩的调控。

Atrophy Signaling in Diaphragm of COPD Rats and Relationship with IL-17

Objective To investigate the expressions of ubiquitin-proteasome markers,including E2-14K,MAFbx,MuRF-1,and nuclear factor-κB（NF-κB） p50,in diaphragm of COPD rats,and their relationship with IL-17 level in diaphragm and serum in order to elucidate the potential mechanism of diaphragm atrophy.Methods Thirty healthy adult male SD rats were randomly divided into a model group（n=18） and a normal control group（n=12）.The COPD rat model was established by instillation of lipopolysaccharide（LPS） and exposure to cigarette smoke for 28 days.The protein levels of E2-14K,MAFbx,MuRF-1,and NF-κB p50 in diaphragm were measured by Western blot.The concentration of IL-17 in serum and diaphragm was measured by ELISA.Results Western blot showed that the protein expressions of E2-14K,MAFbx,MuRF-1,and NF-κB p50 in diaphragm increased significantly in the COPD model group compared with the normal control group （0.96±0.12 vs.0.53±0.09,0.99±0.10 vs.0.53±0.08,0.95±0.08 vs.0.51±0.16,1.11±0.10 vs.0.64±0.50,respectively,P0.01）.The IL-17 level in serum and diaphragm was significantly higher in the COPD group than the control group.The expression of NF-κB p50 was positively correlated with E2-14K,MAFbx,and MuRF-1 expressions（r=0.82,0.92,0.86,respectively,P0.01）.Both in serum and diaphragm,IL-17 level was positively correlated with the percentage of neutrophils,levels of NF-κB p50,E2-14K,MAFbx,and MuRF-1 expressions（all P0.01）.The IL-17 levels in serum and diaphragm were also positively correlated each other（r=0.84,P0.01）.Conclusions The results show that the ubiquitin-proteasom pathway,the NF-κB pathway and IL-17 are up-regulated in diaphragm of COPD rats.These alterations may contribute to diaphragm atrophy in COPD.