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目的观察二甲双胍对内皮细胞1型血管紧张素II受体(AT1R)表达的影响并探讨其机制。方法应用western-blot检测内皮细胞AT1R、腺苷酸活化蛋白激酶α亚基(AMPKα)、核转录因子κB抑制蛋白(I-κB)的表达,应用激光共聚焦观察核转录因子κB(NF-κB)P65在细胞核内变化,比色法测定各组内皮细胞培养液乳酸脱氢酶(LDH)活性。同时应用RNA干扰技术,进一步观察I-κB、AMPKα的作用。结果二甲双胍显著减少肿瘤坏死因子α(TNFα)诱导的内皮细胞AT1R的蛋白表达(P<0.01),显著降低I-κB的磷酸化(P<0.01),同时二甲双胍显著降低内皮细胞培养液LDH活性(P<0.01),而AMPKαSiRNA干预后,二甲双胍对内皮细胞AT1R的影响作用显著减弱(P<0.01)。结论二甲双胍通过促使AMPKα磷酸化,激活AMPKα信号通路,抑制NF-κB活化和内皮细胞AT1R的表达,减轻内皮细胞损伤,保护内皮细胞功能,从而发挥其对心血管的有益作用。
Objective To observe the effect of metformin on the expression of angiotensin II type 1 receptor (AT1R) in endothelial cells and its mechanism. Methods The expressions of AT1R, AMPKα and I-κB in endothelial cells were detected by western-blot. The expression of nuclear factor-kappa B (NF-κB) was detected by laser scanning confocal microscope ) P65 in the nucleus changes, colorimetric determination of endothelial cell culture fluid lactate dehydrogenase (LDH) activity. At the same time, RNA interference technology was used to further observe the effects of I-κB and AMPKα. Results Metformin significantly reduced the expression of AT1R in endothelial cells induced by tumor necrosis factor α (TNFα) (P <0.01) and significantly decreased the phosphorylation of I-κB (P <0.01), while metformin significantly reduced the activity of LDH in endothelial cells P <0.01). However, the effect of metformin on AT1R in endothelial cells was significantly weakened after intervention with AMPKαSiRNA (P <0.01). Conclusion Metformin can exert its beneficial effect on the cardiovascular system by phosphorylating AMPKα, activating AMPKα signaling pathway, inhibiting the activation of NF-κB and the expression of AT1R in endothelial cells, reducing endothelial cell injury and protecting endothelial cells.