Luo Bai-Ling, Niu Rui-Chao, Feng Jun-Tao, Hu Cheng-Ping, Xie Xiao-Yun, Ma Li-Juan
Department of Respiratory Medicine, Xiangya Hospital of Central South University, Hunan Province, Changsha, PR China.
Arch Med Res. 2008 May;39(4):388-96. doi: 10.1016/j.arcmed.2008.02.002.
Secretory leukocyte proteinase inhibitor (SLPI) is an important antileukoprotease in airway. The aim of the present study was to explore the expression of SLPI in the bronchi and lung tissues of chronic obstructive pulmonary disease (COPD) models and the regulative mechanism by transforming growth factor (TGF)beta(1)/Smads signal pathway in bronchial epithelial cell.
COPD rat model was established and was treated with or without TGFbeta1 monoclonal antibody. Spirometry was conducted, and expressions of TGFbeta(1), Smad4 and SLPI were examined by immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR), respectively. The normal human bronchial epithelial cell (NHBE) was cultured, preincubated with or without siRNA (Smad4), and then stimulated with TGFbeta(1). Expressions of Smad4 and SLPI were detected by immunocytochemistry, Western blot and RT-PCR, respectively.
As compared with the model group, after treatment with TGFbeta(1) monoclonal antibody, peak expiratory flow (PEF), forced expiratory volume in 0.3 sec (FEV(0.3)) and FEV(0.3)/forced vital capacity (FVC) in the TGFbeta(1) monoclonal antibody intervention group were all significantly improved. Expression of SLPI was also improved, but expression of Smad4 was significantly decreased. Expression of SLPI in NHBE cells was inhibited by TGFbeta(1) both at the mRNA level and the protein level. Furthermore, effect of TGFbeta(1)-inhibited expression of SLPI in NHBE cells was disengaged by siRNA (Smad4) both at the mRNA level and the protein level.
Decreased expression of SLPI in the COPD rat model may be mainly caused by the increased expression of TGFbeta(1), and this process is probably related to the activation of Smads signal pathway.
分泌型白细胞蛋白酶抑制剂（SLPI）是气道中一种重要的抗白细胞蛋白酶。本研究旨在探讨SLPI在慢性阻塞性肺疾病（COPD）模型支气管和肺组织中的表达，以及转化生长因子（TGF）β1/Smads信号通路对支气管上皮细胞的调控机制。
建立COPD大鼠模型，并给予或不给予TGFβ1单克隆抗体治疗。进行肺功能测定，分别通过免疫组织化学和逆转录聚合酶链反应（RT-PCR）检测TGFβ1、Smad4和SLPI的表达。培养正常人支气管上皮细胞（NHBE），用或不用小干扰RNA（siRNA）（Smad4）预孵育，然后用TGFβ1刺激。分别通过免疫细胞化学、蛋白质印迹法和RT-PCR检测Smad4和SLPI的表达。
与模型组相比，TGFβ1单克隆抗体干预组给予TGFβ1单克隆抗体治疗后，呼气峰值流速（PEF）、0.3秒用力呼气容积（FEV(0.3)）和FEV(0.3)/用力肺活量（FVC）均显著改善。SLPI的表达也有所改善，但Smad4的表达显著降低。TGFβ1在mRNA水平和蛋白质水平均抑制NHBE细胞中SLPI的表达。此外，siRNA（Smad4）在mRNA水平和蛋白质水平均解除了TGFβ1对NHBE细胞中SLPI表达的抑制作用。
COPD大鼠模型中SLPI表达降低可能主要是由于TGFβ1表达增加所致，这一过程可能与Smads信号通路的激活有关。
