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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 relationship between the expression of angiotensin-converting enzyme 2 (ACE2) and oxidative stress injury induced by oxidized low-density lipoprotein (ox-LDL) in macrophages and explore the antioxidative effect of ACE2. Methods RAW 264.7 foam cells were induced by different concentrations of ox-LDL, the lipid accumulation in macrophages was observed by oil red O staining, and the contents of intracellular lipid droplets were quantified. The contents of malondialdehyde (MDA) content of the cell oxidative damage, the expression of ACE2 and MAS m RNA were detected by real-time PCR, the activity of superoxide dismutase (SOD) and the content of reduced glutathione Peptide (GSH) content. Results Macrophages were treated with ox-LDL at different concentrations (20, 40, 60 and 80 mg / L) for 24 h. The macrophages were enlarged and rounded with oil red O staining and the lipid droplets in cytoplasm increased in a dose- Compared with control group, the content of MDA in macrophage foam model group induced by 60mg / L ox-LDL was significantly increased (P <0.01). Real-time PCR results showed that the expression of ACE2 and MAS mRNA in model group was significantly higher than that in control group (P <0.05). Compared with the control group, the activity of SOD and the content of GSH in the model group decreased significantly (P <0.05 or P <0.01). Conclusions The process of foam cell oxidative damage in macrophages is closely related to the down-regulation of ACE2 and its receptor MAS, suggesting that ACE2 may have antioxidant activity. The mechanism may be related to SOD and GSH.