普洱茶通过降低NF-κB活性促巨噬细胞凋亡改善动脉粥样硬化

Pu-erh tea’s anti-atherosclerosis mechanism by reducing the expression and activity of NF-κB and promoting macrophage apoptosis

目的探讨普洱茶通过降低NF-κB表达及活性,促进巨噬细胞凋亡,发挥抗动脉粥样硬化的作用机制。方法载脂蛋白E缺陷(ApoE^-/-)小鼠喂饲普洱茶提取物8周和16周,观察主动脉斑块CD68阳性率及脂质斑块面积;细胞凋亡检测试剂盒检测巨噬细胞凋亡;实时定量PCR、Western blot检测主动脉斑块内及巨噬细胞内P65、IκB-βmRNA及蛋白表达;检测主动脉斑块内各炎症因子mRNA表达变化;电泳迁移率变化(EMSA)分析NF-κBDNA结合活性。结果ApoE^-/-小鼠经普洱茶提取物干预16周组脂质斑块面积分数及脂质成分面积较对照组明显降低(P均<0.05)。普洱茶提取物干预8周、16周组斑块内CD68阳性率较对照组降低(P<0.05);主动脉斑块中巨噬细胞凋亡率增加(P<0.05)。普洱茶提取物干预8周、16周组巨噬细胞中p65mRNA及蛋白表达较对照组降低(P<0.05);16周干预组IκB-βmRNA及蛋白表达降低(P<0.05),主动脉组织中IL-6、IL-12和TNFα的相对表达水平分别较对照组下降(P均<0.05);IL-8、IL-18、MMP9、ICAM和VCAM的表达与对照组差异无统计学意义(P>0.05)。8周、16周干预组NF-κBDNA结合活性平均灰度值均较对照组降低(P<0.05)。结论普洱茶可能通过抑制NF-κB表达及活性而非通过IκB介导,促进巨噬细胞凋亡,同时降低体内炎症水平,进而发挥抗动脉粥样硬化作用。

Objective To explore the anti-atherosclerosis mechanism of pu-erh tea by reducing the expression and activity of NF-κB and promoting macrophage apoptosis. Methods ① ApoE ^-/- mice were fed with pu-erh tea extract for 8 and 16 weeks to observe the positive rate of CD68 and the area of lipid plaque.② Apoptosis detection kit was used to detect the apoptosis of macrophages.③ P65 and IkB-β expressions in aortic plaque and macrophages were detected by Real-time quantitative PCR and Western blot;the expressions of inflammatory factors in aortic plaque were detected.④ Electrophoretic mobility change assay (EMSA) was used to analyze the binding activity of NF-κB DNA. Results ① The area fraction of lipid plaque in ApoE ^-/- mice in the 16-week intervention group was significantly reduced ( vs . control group, P <0.05). The area of lipid components in the 16-week intervention group was significantly reduced ( vs . control group, P <0.05).② The positive rate of CD68 in the plaque was significantly lower in the 8-week and 16-week intervention group than in the control group ( vs . control group, P <0.05). The apoptosis rate of macrophages in aortic plaque ( vs . control group, P <0.05).③ The expressions of p65 gene and protein in macrophages of pu-erh tea extract intervention group 8 and 16 weeks decreased ( vs . control group, P <0.05). The expressions of I-κBβ gene and protein in 16-week intervention group decreased ( vs . control group, P <0.05). The relative expression levels of IL-6,IL-12 and TNF-α in aorta tissue of 16-week intervention group decreased compared with control group ( vs . control group,all P <0.05). There was no significant difference in the expressions of IL-8,IL-18,MMP9,ICAM and VCAM between the two groups ( vs . control group,all P >0.05).④ The average gray value of NF-κB DNA binding activity in the 8- and 16-week intervention groups decreased respectively ( vs . control group, P <0.05). Conclusion Pu-erh tea may play an anti-atherosclerosis role by inhibiting the expression and activity of NF-κB,promoting the apoptosis of macrophages and reducing the level of inflammation in vivo . This mechanism may not be mediated by I κB.