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目的:探讨大鼠肺动脉高压(PAH)过程中TGF-β1对胰岛素样生长因子结合蛋白(IGFBP)表达调节是否依赖于PI3K及ERK信号通路。方法:取健康成年SD大鼠26只,随机分成2组:PAH组,腹腔注射1%的野百合碱,剂量为60 mg/kg;对照(C)组腹腔注射生理盐水。于4周后超声检测肺动脉平均压力,取肺组织做HE染色,应用NIS-Element系统测量中膜厚度。原代培养肺动脉平滑肌(PASMC)细胞,分别加入TGF-β1及TGF-β1中和抗体后,Western-blot检测IGFBP3,IGFBP5,Smad2/Smad3表达。加入ERK特异性抑制剂PD98059或PI3K抑制剂LY294002,检测IGFBP3,IGFBP5表达。结果:野百合碱处理4周后,肺动脉高压组的平均肺动脉压力及右室/(左室+室间隔)比值显著高于对照组。TGF-β1可显著升高IGFBP3,IGFBP5及p-Smad3的表达(P<0.05),而抑制TGF-β1则可显著降低三种蛋白的表达(P<0.05)。加入LY294002抑制PI3K ERK后,IGFBP3和p-Smad2两种蛋白的表达量显著下调(P<0.05)。加入PD98059抑制ERK后可显著降低IGFBP3及IGFBP5的表达水平(P<0.05)。结论:PAH中TGF-β1升高可通过活化Smad2/Smad3上调IGFBP3和IGFBP5的表达。TGF-β1促进IGFBP3,IGFBP5表达的作用依赖于PI3K及ERK信号通路。
AIM: To investigate whether TGF-β1 regulates the expression of insulin-like growth factor-binding protein (IGFBP) in rat pulmonary hypertension (PAH) dependent on the PI3K and ERK signaling pathways. Methods: Twenty-six healthy adult Sprague-Dawley rats were randomly divided into 2 groups: PAH group, intraperitoneal injection of monocrotaline 1% and dose of 60 mg / kg; control group (C) received intraperitoneal injection of saline. After 4 weeks, the average pulmonary artery pressure was measured by ultrasound. The lung tissue was taken for HE staining. The thickness of the media was measured by NIS-Element system. Primary culture of pulmonary artery smooth muscle (PASMC) cells, respectively, after adding TGF-β1 and TGF-β1 neutralizing antibody, Western-blot detected IGFBP3, IGFBP5, Smad2 / Smad3 expression. The ERK specific inhibitor PD98059 or PI3K inhibitor LY294002 was added to detect the expression of IGFBP3 and IGFBP5. Results: After 4 weeks of monocrotaline treatment, the mean pulmonary artery pressure and right ventricular / (left ventricular + interventricular septum) ratio in pulmonary hypertension group were significantly higher than those in control group. TGF-β1 significantly increased the expression of IGFBP3, IGFBP5 and p-Smad3 (P <0.05), while inhibited TGF-β1 significantly decreased the expression of three proteins (P <0.05). After adding LY294002 to inhibit PI3K ERK, the expression of IGFBP3 and p-Smad2 were significantly down-regulated (P <0.05). The addition of PD98059 inhibited ERK significantly reduced the expression of IGFBP3 and IGFBP5 (P <0.05). Conclusion: Increased TGF-β1 in PAH up-regulates the expression of IGFBP3 and IGFBP5 by activating Smad2 / Smad3. The role of TGF-β1 in promoting IGFBP3 and IGFBP5 expression depends on the PI3K and ERK signaling pathways.