中文摘要：

目的：观察炎症能否干扰过氧化物酶体增殖物活化受体γ（PPARγ）-肝X受体α（LXRα）-三磷酸腺苷结合盒转运体A1（ABCA1）途径介导的人肾小球系膜细胞（HMCs）的胆固醇外流。方法：将HMCs分为4组：对照组、高脂组[细胞给予100 mg/L低密度脂蛋白（LDL）处理]、炎症组[细胞给予20μg/L肿瘤坏死因子-α（TNF-α）处理]、联合干预组（细胞给予20μg/L TNF-α＋100 mg/L LDL处理）。采用实时定量PCR和W esternb lotting方法检测PPARγ、LXRα和ABCA1的mRNA及蛋白表达水平。用[3H]标记胆固醇,液体闪烁计数法检测胆固醇外流量。用油红O染色法及化学酶促-比色法观察HMCs中脂质积聚情况。结果：与对照组相比,高脂组PPARγ、LXRα和ABCA1 mRNA及蛋白的表达明显增加,单纯的炎症刺激可下调它们的表达,而联合干预组中上述各基因和蛋白表达量比高脂组明显下降。胆固醇外流测定结果显示：与对照组相比,高脂组胆固醇外流量增加,而炎症组胆固醇外流量降低,联合干预组比高脂组胆固醇外流量明显减少。油红O染色提示联合干预组细胞内脂质积聚明显高于其余3组。细胞内胆固醇含量测定亦显示炎症能进一步加重胞内脂质积聚。结论：炎症因子可通过抑制PPARγ-LXRα-ABCA1表达导致HMCs胆固醇外流减少,加重细胞内脂质积聚。

英文摘要：

AIM：To investigate the perturbative effects of inflammatory stress on cholesterol efflux in human kidney mesangial cells（HMCs） and the relation to peroxisome proliferators activated receptor-γ（PPARγ）-1iver X activated receptor-α（LXRα）-and ATP-binding cassette transporter A1（ABCA1） pathway.METHODS： HMCs were cultured and divided into control group（incubated with serum free medium）,high lipid group [treated with serum free medium plus low density lipoprotein（LDL,100 mg/L）],inflammatory stress group [treated with tumor necrosis factor-α（TNF-α,20 μg/L）] or combination treatment group [treated with TNF-α（20 μg/L） plus LDL（100 mg/L）].The mRNA and protein levels of PPARγ,LXRα,ABCA1 were examined by real-time polymerase chain reaction（PCR） and Western blotting. cholesterol assay was performed to evaluate the efflux of cholesterol by liquid scintillation counter.Oil red O staining was used to evaluate lipid droplet accumulation in the cells.Intracellular cholesterol level was measured by enzymic assay.RESULTS： ： LDL increased the expression of PPARγ,LXRα and ABCA1 at mRNA and protein levels in HMCs,while TNF-α reduced the expression of these genes at mRNA and protein levels.The cholesterol efflux was increased after LDL loading.However,inflammatory stress inhibited cholesterol efflux in the absence or presence of LDL loading.Oil red O staining and quantitative analysis showed that LDL loading increased the intracellular cholesterol level in HMCs and inflammatory stress further exacerbated the lipid accumulation.CONCLUSION： Inflammatory cytokine reduces cholesterol efflux by inhibiting the expression of PPARγ,LXRα and ABCA1,thereby causing lipid accumulation in HMCs.