蚤休薯蓣皂苷对内皮细胞的保护作用涉及TLR4/NF-κB途径

目的观察蚤休薯蓣皂苷(Rhizome Dioscin,RD)对氧化性低密度脂蛋白(ox-LDL)诱导人脐静脉内皮细胞(HU-VEC)损伤对细胞生长、炎症反应Toll样受体4(TLR4)和细胞核因子κB(nuclear factor kappa B,NF-κB)表达的影响,探讨RD抗动脉粥样硬化(AS)的作用机制。方法体外培养HUVEC,RD 3个浓度预处理,加入ox-LDL,运用流式细胞术PI染色检测细胞周期,激光共聚焦显微镜JC-1染色检测线粒体电位(ΔΨm),Western blot检测TLR4和NF-κB蛋白的表达。结果与正常对照组相比,经ox-LDL损伤后HU-VEC细胞周期阻滞在G0/G1期,表现为G0/G1期细胞比例明显升高(P<0.01),S期细胞比例明显下降(P<0.01);细胞ΔΨm明显下降;TLR4和NF-κB的表达与正常组比较均升高。RD预处理能抑制ox-LDL诱导的细胞生长停滞,使细胞周期S期细胞比例增加(P<0.01),ΔΨm上升,TLR4和NF-κB的表达与损伤组相比均下降。结论抑制TLR4/NF-κB信号转导途径可能是RD抗内皮细胞氧化损伤、阻止经线粒体途径的细胞生长停滞的可能机制之一。

Effect of rhizome saponins on TLR4 signal transduction pathways on ox-LDL damaged human endothelial cells

Aim To observe the effect of Rhizome Di-oscin(RD)on cell growth,Toll like receptor 4(TLR4) and the nuclear factor kappa B(NF-κB)signal transduction pathways on human umbilical vein endothelial cells HUVEC damaged by oxidizing low density lipoprotein(ox-LDL),and to discuss the anti-atherosclerosis(AS)mechanism of the RD.Methods Three concentration RD pretreated,HUVEC cultured in vitro,flow cytometry was used to detect cell cycle.Laser scanning confocal microscope JC-1 dyeing to detect mitochondria membrane potential(ΔΨm)and western blot to test TLR4 and the NF-κB protein expression. Results Cell cycle in ox-LDL injured group was blocked in G 0 / G 1 phase and cell number of G 0 / G 1 phase was increased(P < 0.01)but cell number of S phase was decreased(P < 0.01).The mitochondrial membrane potential was obviously decreased,expression of TLR4 and the NF-κB in injured group were increased compared with normal control.RD group could block cell growth stagnation induced by ox-LDL,make the cell number of G 0 / G 1 phase decrease and S phase increase in the meantime(P < 0.01),ΔΨm rose. TLR4 and NF-κB expression were decreased compared with injured control.Conclusion RD can inhibit TLR4 / NF-κB signal transduction pathway on HUVEC, restrain the mitochondrial oxidative damage by the way of cell growth stagnation and this may be one of the possible mechanisms of anti-AS of RD.