EGCG对小鼠白色脂肪组织巨噬细胞极化的调控作用及其分子机制研究

REGULATION OF POLARIZATION OF THE MACROPHAGES FROM WHITE ADIPOSE TISSUE BY(-)-EPIGALLOCATECHIN-3-GALLATE IN MICE AND ITS MOLECULAR MECHAISM

目的研究表没食子儿茶素没食子酸酯(EGCG)干预对白色脂肪组织M1/M2型巨噬细胞极化的影响及其可能的作用机制。方法30只3w龄离乳C57BL/6J雄性小鼠,随机分为:正常对照组(喂饲基础饲料),高脂饮食组(喂饲高脂饲料),EGCG干预组(喂饲高脂饲料,并给予含0.2%~0.5%EGCG的饮用水)3组。持续喂养10w后,处死小鼠。检测肥胖指标(体重、内脏脂肪重量),糖脂代谢指标(空腹血糖、甘油三酯、总胆固醇、低密度胆固醇);免疫组织化学检测附睾脂肪中的巨噬细胞特异性抗体Mac-2和CD68;RT-PCR检测肠系膜脂肪组织M1型巨噬细胞标志物INOS和CD11c,M2型巨噬细胞标志物Arg-1、CD206和抑炎因子IL-10以及核因子E2相关因子(Nrf2)及其下游血红蛋白加氧酶-1(HO-1)mRNA的表达水平;流式技术检测附睾脂肪组织中M1型和M2型巨噬细胞的比例。结果高脂饮食组小鼠Lee’s指数、血清甘油三酯水平均显著高于正常对照组(P<0.05),而EGCG能显著降低高脂饮食组上述这些指标(P<0.05)。高脂饮食组小鼠脂肪组织中M1型巨噬细胞标志物INOS、CD11c的mRNA表达水平和Mac-2、CD68阳性细胞数均显著高于正常对照组(P<0.05),而EGCG干预组CD11c表达水平显著低于高脂饮食组(P<0.05),其余指标也存在降低的趋势(P>0.05);高脂饮食组小鼠的M2型巨噬细胞较正常对照组减少,而EGCG干预则使其数量增加,但无统计学差异(P>0.05)。EGCG干预组脂肪组织中Nrf2 mRNA的表达水平较另外两组有上调的趋势(P>0.05)。结论EGCG干预能够抑制高脂饮食诱导的M1型巨噬细胞极化,其作用机制可能与上调Nrf2/抗氧化反应元件途径有关。

Objective The objective of this study was to investigate the effects of epigallocatechin-3-gallate(EGCG)on the polarization of M1/M2 macrophages from white adipose tissue and the possible mechanism associated with Nrf2/HO-1 signaling pathway.Methods Thirty three-week-old C57 BL/6 J male mice were randomly divided into three groups:normal control group,high-fat diet group(fed with a high-fat diet),and EGCG intervention group(fed with a high-fat diet plus 0.2%-0.5%EGCG in water).After feeding for 10 weeks,the mice were sacrificed.The obesity index(body weight,visceral fat weight),glucose and lipid metabolism indicators(FBG,TG,TC,HDL,LDL)were measured.Immunohistoc-hemistry was used to observe the expression of macrophage-specific antibodies CD68 and Mac-2 in epididymal fat tissue.The expression of nuclear factor E2 related factor(Nrf2)and its downstream hemoglobin oxygenase-1(HO-1),M1 macrophage markers(INOS and CD11 c),M2 macrophage markers(Arg-1 and CD206)and anti-inflammatory factor IL-10 mRNA in mesenteric adipose tissue were detected by RT-PCR.The proportion of M1/M2 macrophages in epididymal fat tissue were also detected by flow cytometry.Results The Lee’s index,mesenteric fat weight,serum TG level,and fat cell volume in the high-fat diet group were significantly higher than those in the normal control group(P<0.05).EGCG could effectively reduce these indicators in the high-fat diet group(P<0.05).Compared with the normal control group,the mRNA expression of M1 type macrophage markers INOS,CD11 c and the number of Mac-2,CD68 positive cells in the adipose tissue were significantly higher in the high-fat diet group(P<0.05),while EGCG could significantly reduce the increased expression of M1 macrophage marker CD11 c induced by high foot diet(P<0.05),and the other indicators also showed a tendency to decrease(P>0.05).M2 macrophages in the high-fat diet group decreased compared with the normal control group,and the EGCG intervention group could reverse this change,but there was no statistical difference(P>0.05).Nrf2 had a trend to be up-regulated in adipose tissue by EGCG intervention(P>0.05).Conclusion EGCG could inhibit the increase of M1 macrophages induced by high-fat diet,and the Nrf2-ARE pathway is involved.