低氧促进大鼠肺动脉平滑肌细胞Periostin表达及其信号转导机制

观察低氧对大鼠肺动脉平滑肌细胞（pulmonary artery smooth muscle cells，PASMCs）Periostin表达的影响及其相关信号转导机制。胶原酶I法原代培养PASMCs，经低氧（5％O2）分别处理PASMCs2，6，12，24h后，RT-PCR和Western blot法检测Periostin mRNA和蛋白表达。加入PI3K/Akt通路特异性抑制剂LY294002（10μmol／L）进行干预，Western blot分析比较不同条件下低氧处理24h后大鼠PASMCs中Periostin和Akt／P-Akt的蛋白表达。结果表日月，与常氧组比较，低氧处理6h组、12h组和24h纽Periostin mRNA和蛋白的表达均显著上升（P〈0．05，P〈0．01），低氧处理后的PASMCs中Periostin mRNA和蛋白的表达逐渐升高：低氧处理2h组无显著差异（P〉0．05）。用LY294002对PASMCs处理，并低氧24h后，Periostin的表达被显著抑制（P〈0．01），细胞P-Akt的表达下调（P〈0．05），总Akt的蛋白表达没有明显差异（P〉0．05）。推测低氧可诱导大鼠PASMCs中Periostin mRNA和蛋白的表达上调。低氧可能通过激活P13K/Akt通路促进Akt的磷酸化，进而使Periostin在PASMCs中过表达，提示Periostin在低氧性PASMCs增殖过程中可能起着重要作用。

Hypoxia Increases Periostin Expression and the Related Signal Pathway in Rat Pulmonary arter Smooth Muscle Cells

The effects of hypoxia on the Periostin expression and the related signal transduction pathway in rat pulmonary arterials mooth muscle cells （PASMCs） were observed in this study. Primary PASMCs were cultured with collagenase I. The PASMCs were treated at hypoxia （5% O2） for 2, 6, 12, 24 h separately. The expressions of Periostin mRNA and protein in PASMCs of rat were detected by RT-PCR and Western blot. LY294002 （10 μmol/L）, a specific inhibitor of PI3FUAkt signal pathway, was used to treat PAMSCs at hypoxia for 24 h. Periostin and Akt/ P-Akt protein were detected by Western blot. Compared with control group, the mRNA and protein expressions of Periostin increased significantly in hypoxia PASMCs treated for 6, 12, 24 h （P〈0.05, P〈0.01）, and there was no significant difference between normal group and hypoxia 2 h group （P〉0.05）. After treated with LY294002 for 24 h at hypoxia, the expressions of Periostin and P-Akt were down-regulate significantly （P〈0.01, P〈0.05） compared with hypoxia 24 h group. But there was no significant difference for Akt protein expression （P〉0.05）. The results suggested that hypoxia exposure could upregulate the mRNA and protein expressions of Periostin in PASMCs. Hypoxia exposure might activate the PI3K/Akt signal pathway, promote Akt phosphorylation, and then induce Periostin protein overexpression. It indicated that Periostin might play an important role in hypoxia-induced PASMCs proliferation.