表没食子儿茶素没食子酸酯对泡沫细胞中胆固醇流出的影响及机制

Effect of epigallocatechin-3 gallate on cholesterol efflux in foam cells and its mechanism

目的探讨表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)对泡沫细胞中胆固醇流出的影响及其机制。方法人单核细胞白血病细胞诱导分化为巨噬细胞再转化为泡沫细胞,将细胞分为对照组,低、中和高剂量组,每组1.5×10~6个细胞,分别用0,10,30,100μmol/L EGCG干预后,胆固醇检测试剂盒检测细胞中胆固醇含量,液体闪烁计数仪检测载脂蛋白A-Ⅰ介导的泡沫细胞胆固醇流出,蛋白质印迹检测三磷酸腺苷结合盒转运体A1(ATP-binding cassette A1,ABCA1)蛋白质表达,实时荧光定量PCR检测ABCA1mRNA的表达。结果与对照组比较,低、中和高剂量组泡沫细胞ABCA1mRNA和蛋白表达明显升高(P<0.01),胆固醇流出率升高[(7.04±0.21)%、(7.75±0.17)%、(8.53±0.18)%vs(3.37±0.16)%,P<0.01],胆固醇含量降低[(419.33±19.75)mg/g、(352.58±14.23)mg/g、(312.62±17.45)mg/g vs(520.51±20.62)mg/g,P<0.01],且中剂量组和高剂量组胆固醇流出率、胆固醇含量和ABCA1蛋白表达均较低剂量组变化明显(P<0.05)。结论 EGCG通过上调ABCA1的转录与表达,促进胆固醇流出,减轻细胞中胆固醇负荷。

Objective To study the effect of epigallocatechin-3 gallate （EGCG） on cholesterol efflux in foam cells and its mechanism. Methods THP-1 cells were induced to differentiate into macrophages which were then transformed to foam cells. Foam cells were divided into 0 μmol/L EGCG group, 10 μmol/L EGCG group, 30 μmol/L EGCG group, and 100 μmol/L EGCG group （1. 5 × 10^6 in each group）. Their cholesterol content was measured with a cholesterol test kit, apoA-I- mediated cholesterol efflux was assayed with a liquid scintillation counter, expression of ATP- binding cassette A1 （ABCA1） was detected by RT-PCR and Western blot respectively. Results The ABCA1 mRNA and protein expression levels and cholesterol efflux were significantly higher while the cholesterol content was significantly lower in 10 μmol/L EGCG group, 30 μmol/L EGCG group,and 100 μmol/L EGCG group than in 0 μmol/L EGCG group （7.04% ±0.21%, 7.75%±0.17% and 8.53%±0.18% vs 3.37%±0.16%,P〈0.01;419.33±19.75 mg/g,352.58±14.23 mg/g and 312. 62±17.45 mg/g vs 520. 51±20. 62 mg/g,P〈0.01）,and in 30 μmol/L EGCG group, 100μmol/L EGCG group than in 10 μmol/L EGCG group （P〈0.05）. Conclusion EGCG increases cholesterol efflux and decreases cholesterol content in foam cells by upregulating the transcription and expression of ABCA1.