低氧时蛋白激酶C对内皮细胞表达血管内皮生长因子的调节作用

目的探讨低氧培养大鼠肺动脉血管内皮细胞生长因子 (VEGF)表达变化与蛋白激酶C(PKC)活性的关系。方法培养大鼠肺动脉血管内皮细胞 ,观察低氧 ( 1 %O2 )培养 0、1、3、6、1 2h大鼠肺动脉血管内皮细胞PKC活性和VEGFmRNA水平变化 ;同时对培养液中VEGF蛋白水平进行测定。培养基中加入PKC抑制剂 (staurosporine)后 ,立即进行低氧培养 ,测定低氧培养不同时间点上述指标的变化。 结果低氧培养 1hPKC活性首先明显升高 (P >0 .0 5 ) ,至 3hVEGFmRNA表达明显升高 (P <0 .0 1 ) ,6h培养液中VEGF蛋白水平显著升高 (P <0 .0 1 )。而加入PKC抑制剂后 ,低氧培养的内皮细胞PKC活性与 0h比较明显下降 (P <0 .0 1 ) ,相应各时间点的VEGFmRNA及蛋白水平与 0h比较无明显变化 (P >0 .0 5 )。结论低氧能够刺激大鼠肺动脉血管内皮细胞VEGF表达升高 ,低氧时PKC活性升高是调节VEGF表达升高的重要因素之一

Vascular Endothelial Growth Factor Gene Expression Regulated by Protein Kinase C Pathway in Endothelial Cells during Hypoxia

Objective. To investigate the relationship between Vascular endothelial growth factor (VEGF) gene expression and protein kinase C (PKC) activity. Method. 1) Rat's primary pulmonary artery endothelial cells (PAEC) were cultured under hypoxia condition (1% O2). Changes of PKC activity and VEGF mRNA in PAEC were detected at 0 (control), 1, 3, 6, and 12 h in the hypoxic condition of culture. 2) After addition of PKC inhibitor (staurosporine) in culture medium and culturing PAEC in hypoxic condition immediately, PKC activity and VEGF mRNA in PAEC were measured at the same time. VEGF protein in culture medium under the two conditions above were also detected. Result. PKC activity in PAEC were obviously elevated at 1 h during hypoxia as compared with the control (P<0.05); VEGF mRNA expression in PAEC and VEGF protein level in culture medium were increased significantly (P<0.01) at 3 h and 6 h during hypoxia respectively as compared with the control (P<0.01); After addition of PKC inhibitor in culture medium and culturing cells in hypoxia condition immediately, PKC activity in PAEC decreased significantly as compared with that at 0 h (P<0.01), and there were no significant changes of VEGF mRNA in PAEC and VEGF protein level in culture medium at any time (P>0.05). Conclusion. The results demonstrate that hypoxia stimulates pulmonary arterial vascular endothelial cells to secrete VEGF, and PKC may be one of the factors that up-regulate VEGF gene expression during hypoxia.