蛋白激酶C抑制剂对高糖致血管内皮细胞高通透性的保护作用

摘要

Objective To investigate the effect of different concentrations of glucose on the permeability of human umbilical vein endothelial cell monolayer and the protective effect of protein kinase C (PKC) inhibitor Ro-31-8425 against high-glucose exposure. Methods Cultured human umbilical vein endothelial cell line EA.hy926 cells were exposed to 5.5 mmol/L glucose (control) and high-concentration glucose (10, 15, 20, 25.5, and 30 mmol/L), and the endothelial monolayer permeability was assessed by measuring the flux of FITC-labeled dextran (FITC-DX) across the endothelial cells. The cultured EA.hy926 cells were treated with 5.5 mmol/L glucose + saline, high glucose (25.5 mmiol/L) + saline, or high glucose (25.5 mmol/L) + Ro-31-8425 (10 μmol/L), and the level of PKC phosphorylation and endothelial monolayer permeability were evaluated. Results High glucose dose-dependently increased the permeability of the endothelial cell monolayer (P＜0.01), and glucose at 25.5 mmol/L significantly increased the phosphorylation level of PKCα and PKCβ Ⅱ in the cells (P＜0.01). Treatment with 10 μmol/L Ro-31-8425 obviously attenuated high-glucose-induced PKCα and PKCβ Ⅱ phosphorylation (P＜0.01) as well as the increase of the cell monolayer permeability (P＜0.01). Conclusion High glucose increases the hyperpermeability of human umbilical vein endothelial cell monolayer mediated by the phosphorylation of PKC, and the PKC inhibitor Ro-31-8425 can reverse such effects.%目的 探讨不同浓度糖对人脐静脉内皮细胞通透性的影响,以及蛋白激酶C(PKC)抑制剂Ro-31-8425对高糖刺激下血管内皮的保护作用.方法 体外培养人脐静脉内皮细胞株(EA.hy926),选取3～4代细胞进行实验.分为对照组(5.5 mmol/L)、糖刺激组(10、15、20、25.5、30 mmol/L),采用测定异硫氰酸萤光素-右旋糖酐(FITC-DX)透过Transwell小室荧光强度的方法,研究不同浓度高糖对EA.hy926单层细胞通透性的影响.再选取25.5 mmol/L为高糖组,此时可分为对照组(5.5 mmol/L)+生理盐水、高糖(25.5 mmol/L)+生理盐水组、高糖(25.5 mmol/L)+PKC抑制剂Ro-31-8425(10 μmol/L)组,进而探讨高糖对PKC蛋白水平的影响以及PKC抑制剂Ro-31-8425对通透性改变的作用.结果 高于正常血糖的各浓度糖刺激组均可使EA.hy926血管内皮细胞通透性明显增加(P＜0.01),并呈浓度依赖性.25.5 mmol/L高糖可导致PKCα以及PKCβⅡ磷酸化水平上升(P＜0.01).PKC抑制剂Ro-31-8425预处理组可通过抑制高糖刺激下PKCα、PKCβⅡ磷酸化水平上升(P＜0.01),从而抑制血管内皮细胞通透性增加(P＜0.01).结论 高糖可通过激活PKC导致血管内皮细胞通透性受损,PKC抑制剂Ro-31-8425可以降低通透性,起到一定的保护作用.