过氧化体增殖物激活型受体抑制氧化型脂蛋白致血管内皮细胞凋亡

The Roles of Peroxisome Proliferator Activated Receptors on the Apoptosis of Endothelial Cells Induced by Oxidized Lipoprotein

为探讨氧化型低密度脂蛋白和氧化型脂蛋白 (a)对内皮细胞的致凋亡作用 ,以及过氧化体增殖物激活型受体对细胞凋亡的影响。采用TUNEL法、DNA电泳检测氧化型脂蛋白所致内皮细胞的凋亡。过氧化体增殖物激活型受体的配体吉非罗齐和曲格列酮干预后细胞凋亡的变化及核因子κB、白细胞介素 6及其受体表达的变化。细胞免疫组织化学法检测过氧化体增殖物激活型受体α和γ的核移位率 ,酶联免疫吸附测定法检测原代内皮细胞上清夜白细胞介素 6的分泌 ,胞浆抗原FITC标记流式细胞仪技术检测核因子κB、白细胞介素 6及其受体在内皮细胞中的表达。结果发现 ,氧化型低密度脂蛋白和氧化型脂蛋白 (a)在 6、12、18h和 2 4h 4个时间点致内皮细胞凋亡作用逐渐增强。吉非罗齐和曲格列酮可通过活化过氧化体增殖物激活型受体减轻细胞凋亡 ,在氧化型低密度脂蛋白和氧化型脂蛋白 (a)组分别使内皮细胞 18h作用点凋亡率降低为 13%和 16 % (P <0 .0 5 )伴白细胞介素 6及其受体表达降低 ,核因子κB表达无显著差异。结果提示 ,氧化型脂蛋白致内皮细胞的凋亡具有时间依赖性。过氧化体增殖物激活型受体可能通过抑制炎症因子表达从而抑制细胞凋亡。

Aim To investigate the apoptotic function of the oxidized LDL and Lp(a) on the endothelia cells and the roles of PPAR during the process. Methods hUVEC were isolated from fresh umbilical cords obtained at normal deliveries. The LDL and Lp(a) were obtained by density-gradient ultracentrifugation and were oxidized through incubation with 15 μmol/L CuSO 4. The apoptosis of endothelia cells was observed with the oxidized lipoproteins at different time points by the measurements of TUNEL and electronical microscope. The changes among the apoptosis,inflammation factors and NF-κB with the pretreatments of gemfibrozil and troglitazone were observed. The activation of PPARα and PPARγ were tested by immunohistology. The secretion of IL-6 was measured with ELISA. The expression of IL-6R, IL-6 and NF-κB were performed by FACS. Results The oxidized LDL and Lp(a) induced the apoptosis of endothelia cells which was accentuated with 6, 12, 18 and 24 h points. Gemfibrozil and troglitazone relieved the function of oxidized lipoproteins through the activation of PPARα and PPARγ respectively accompanying the lower expression of IL-6 and IL-6R. Conclusions Oxidized lipoprotein can induce the apoptosis of endothelia cells with a time-depended style. PPARα and PPARγ may relieve the apoptosis of vascular cells through the inhibition of inflammation factors.