丝裂原活化蛋白激酶通路在炎性反应导致的支气管哮喘豚鼠呼吸道上皮细胞凋亡中的作用

Effect and influence of mitogen-activated protein kinases pathway on airway inflammation and epithefium apoptosis in asthmatic guinea pigs

目的探讨支气管哮喘豚鼠呼吸道上皮细胞凋亡、炎性反应和p38蛋白激酶（p38MAPK）表达的变化以及地塞米松（DEX）对其的影响。方法将48只豚鼠随机分为正常对照组、哮喘组、DEX干预组和MAPK通路抑制剂SB203580干预组，每组12只。免疫组织化学方法检测肺组织磷酸化p38MAPK表达的变化，ELISA法检测炎性因子水平，呼吸道上皮凋亡水平采用cleavedcaspase．3抗体检测气道上皮凋亡细胞。结果哮喘组呼吸道上皮细胞凋亡（TUNEL染色阳性细胞）、肺组织磷酸化p38MAPK表达水平及支气管肺泡灌洗液（BALF）中IL-5水平均较正常对照组增高（P〈0．01），肺组织磷酸化p38MAPK表达水平、BALF中IL-5水平呈正相关（r=0．916，P〈0．01）；DEX干预组上述指标较哮喘组显著降低（P〈0．01），SB203580组呼吸道上皮细胞凋亡、肺组织磷酸化p38MAPK表达水平较哮喘组显著降低（P〈0．01），而BALF中IL-5水平与哮喘组比较差异无统计学意义（P〉0．05）；同SB203580干预组比较，DEX干预组上述指标降低（P〈0．01）。结论哮喘豚鼠呼吸道慢性炎症参与了呼吸道上皮细胞凋亡，DEX对哮喘豚鼠呼吸道上皮细胞凋亡的干预作用至少部分与抑制磷酸化p38MAPK的表达有关，p38MAPK可能参与了支气管哮喘肺部炎症所导致的呼吸道上皮细胞凋亡过程。

Objective To study the airway inflammation, epithefinm apoptosis, p38 MAPK expression level in asthmatic guinea pigs and the effect of dexmethasone therapy. Methods Forty-eight guinea pigs were randomly divided into 4 groups：control group, asthma group, dexmethasone-treated group and MAPK pathway inhibitor SB203580 trea- ted group, 12 guinea pigs in each group. Hematoxylin and eosin staining, Massong Triehrome stain, Periodic Acid Schif- gtaining were performed. Histological changes were detected under the optical or the electron microscope. Immunohisto- chemistry assays were used to determine the status of IL-5 and phosphorylated p38 MAPK in airway epitheliam. Inflam- matory factor level was detected by enzyme linked immunosorbent assay （ELISA）. Immunohistochemistry assays of cleaved caspase 3 was used to detect the level of epithefium apoptosis. Results Compared with the control group, guinea pigs in the asthmatic group showed significantly higher airway epithelium apoptosis （ detected as the cleaved easpase-3 imumunoreactive cells） ,lung tissue phosphorylated p38 MAPK expression level, IL-5 level in BALF （P 〈 0. 01 ）. Lung tissue phosphorylated p38 MAPK expression level was significantly related to IL-5 level in BALF. Com- pared with the asthmatic group, guinea pigs in the SB203580 group showed significantly lower airway epithelium apopto- sis,lung tissue phosphorylated p38 MAPK expression level （ P 〈 0.01 ）, but not IL-5 level in bronchoalveolar lavage fluid（BALF） （P 〉0.05）. Compared with SB203580 group, guinea pigs in the DEX group showed significantly lower airway epithelium apoptosis, lung tissue phosphorylated p38 MAPK expression level, and IL-5 level in BALF （P 〈 0.01 ）. Conclusions Airway inflammation is involved in epithefium apoptosis in the asthmatic guinea pigs. The inter- fering effect of apoptosis by DEX may be partly related to inhibition of lung tissue phosphorylated p38 MAPK expression level, and p38 MAPK may participate in the asthmatic inflammation and induce airway epithelium apoptosis.