氧化低密度脂蛋白诱导巨噬细胞泡沫化氧化损伤后血管紧张素转化酶2的表达变化及意义

Change of angiotensin-converting enzyme 2 expression in the macrophage foam cell induced by oxidized low density lipoprotein

目的观察氧化低密度脂蛋白(ox-LDL)诱导巨噬细胞泡沫化后血管紧张素转化酶2(ACE2)的表达变化与氧化应激损伤的关系,探讨ACE2的抗氧化作用。方法用不同浓度ox-LDL诱导小鼠巨噬细胞RAW 264.7泡沫化,油红O染色观察巨噬细胞内脂质堆积变化,并定量分析细胞内脂滴含量,通过检测细胞上清中丙二醛(MDA)含量鉴定细胞氧化损伤程度,实时定量聚合酶链反应(Real-time PCR)检测ACE2及MAS m RNA表达,化学比色法检测超氧化物歧化酶(SOD)活性与还原型谷胱甘肽(GSH)的含量。结果不同浓度(20、40、60、80mg/L)ox-LDL处理巨噬细胞24 h,油红O染色可见巨噬细胞变大、变圆,胞质内脂滴含量呈剂量依赖性增加;用60mg/L ox-LDL诱导巨噬细胞泡沫化模型组中MDA含量较对照组明显升高(P<0.01);Real-time PCR结果显示,模型组ACE2和MAS m RNA表达水平较对照组显著减少(P<0.05);与对照组比较,模型组中SOD活性与GSH含量显著降低(P<0.05或P<0.01)。结论巨噬细胞泡沫化氧化损伤进程与ACE2及其下游受体MAS表达下调密切相关,提示ACE2具有一定的抗氧化作用,其机制可能与SOD及GSH有关。

Objective To investigate the change of angiotensin-converting enzyme 2 （ACE2） expression in the macrophage foam cell oxidative damage model induced by oxidized low density lipoprozein（ox-LDL） and to explore if ACE2 is related to anti-oxidative effects. Methods Different concentrations of ox-LDL were used to induce macrophage cell RAW 264.7 into foam ceils, the intracellular lipid droplets amounts were observed by oil red O staining, the content of malondialdehycle（MDA） was measured to identify oxidative damage, Real-time PCR was used to detect ACE2 and MAS mRNA expression; The activity of superoxide dismutase （SOD） and the content of glutathione （GSH） were measured by chemocolorimetry. Results Oil red O staining results showed that the macrophages became larger and rounder after treated by ox-LDL （20, 40, 60, 80mg/L） for 24 hours. The amounts of lipid droplets in the cytoplasm increased in the model group in a dose-dependent manner and 60mg/L ox-LDL treatment achieved the maximum effect （ P 〈 0.01 ）. The MDA content was increased significantly compared with the control group using 60mg/L ox-LDL treatment （ P 〈 0. 01 ）. Real- time PCR results showed that ACE2 and MAS mRNA expression in model group were significantly decreased compared with control group（P 〈 0. 05） , and the SOD activity and the GSH content were also decreased significantly in the model group （P 〈 0. 01 or P 〈 0.05 ）. Conclusion Macrophage foam cell formation and oxidative damage processes maybe closely related with the down-regulation of ACE2 and MAS expression, suggesting that ACE2 has an anti-oxidative effect which maybe related to SOD and GSH.