PPARγ/PGC-1α在支气管哮喘豚鼠肺组织中表达及作用

Expression and Role of PPARγ/PGC-1α in the Lungs of Guinea Pigs with Bronchial Asthma

目的:观察PPARγ和PGC-1α在豚鼠支气管哮喘肺组织中表达而探索PPARγ/PGC-1α对哮喘作用机制。方法:40只健康雄性豚鼠随机化原则分成对照组(A组)、哮喘组(B组)、地塞米松(C组)和罗格列酮治疗组(D组)每组10只豚鼠。卵蛋白致敏法复制哮喘模型,第16天始每日诱喘前30minC组和D组分别给予约3至5ml溶有药物的生理盐水灌胃:C组地塞米松2mg/kg,D组罗格列酮4mg/kg连续14天。测细支气管炎症细胞浸润及支气管重塑指标,肺组织病理;原位杂交和RT-PCR检测PPARγ和PGC-1α的mRNA表达免疫组化和Western blot检测肺组织两者蛋白表达。结果:(1)哮喘组出现了明显气道重塑和炎症细胞浸润,地塞米松和罗格列酮对其起抑制作用。(2)原位杂交和RT-PCR显示PPARγ和PGC-1αmRNA哮喘组表达最低四组差异均有统计学差异(P均<0.01);免疫组化和Western blot显示PPARγ和PGC-1α蛋白哮喘组表达几乎都呈阴性而且以核内表达为主,四组差异均有统计学意义(P均<0.01);地塞米松和罗格列酮可上调PPARα和PGC-1γ蛋白以及mRNA的表达。(3)支气管哮喘豚鼠肺组织PPARγ与PGC-1α表达呈正相关,PPARγ和PGC-1α蛋白以及mRNA与浸润的嗜酸粒细胞、Wal%、SMC-A%呈负相关。结论:PPARγ/PGC-1α在卵蛋白致敏急性支气管哮喘模型中表达下降,罗格列酮和地塞米松一样可上调PPARγ/PGC-1α,PPARγ/PGC-1α对哮喘发病起重要作用而可能为哮喘防治开辟新途径。

Objective： To investigate the expressions and roles of PPARγ and PGC-1α in lung of guinea pigs with Bronchial Asthma. Methods： Forty adult male guinea pigs were randomly divided into 4 groups： the control group（group A）, asthmatic group（group B）, Dexamethasone group （group C） and Rogridone group （group D）, 10 guinea pigs in each group. The asthmatic model was established by the ovalbumin challenge method. In the C and D groups, 30min before inducing asthma,0.9%NS（physiological saline） with medicine was given to each guinea pigs about 3 to 5ml through intragastric administration： Dexamethasone （2mg/kg）in group C, Rogridone （4）in group D from the sixteenth day and for 14 consecutive days. The bronchiole inflammatory cell infiltration and remodeling index, lung tissue histopathological changed were observed. Expressions of PPAR-γ/and PGC-1 mRNA in lung tissue were assayed by in situ hybridization and by RT-PCR; Expressions of PPAR-γ and PGC-1 protein were detected by immunohischemistry and by Western blot. Results： There were obviously bronchiole remodeling response and inflammatory cell infiltration in group B, which can be inhibited by Dexamethasone and Rogfidone. In situ hybridization and RT-PCR showed that the expressions of PPARγ and PGC-1 mRNA in lung tissue were also the lowest in group B and comparison among groups showed statistical significant （all P〈0.01）. Imrnunohistochemistry and Western blot indicated that the A value of PPAR-γ and PGC-1 protein in lung tissue were the lowest in group B, and expressed primarily in nucleus, the differences being statistically significant （all P〈0.01）. Dexamethasone and Rogridone can up-regulate the expressions of PPAR-γ and PGC-1 protein and also both of mRNA. There was positive correlation between PPARγ and PGC-1. PPAR-γ/PGC-1 protein and mRNA were negatively correlated with ESO,Wal% ,SMC-A%. Conclusion： In acute asthmatic models induced by ovalbumin, the expressions of PPARγ/PGC-1α were decreased, and Rogridone can up-regulate their expression same as Dexamethasone, and thus being implicated that PPARγ/PGC-1α may play important roles in the pathogenesis of asthma and possibly starting a new channel for prevention of asthma.