血清淀粉样蛋白A在3T3-L1脂肪细胞的表达及其与胰岛素抵抗的关系

Relationship between expressions of serum amyloid A and insulin resistance in 3T3-L1 adipocytes

目的了解血清淀粉样蛋白A(SAA)在3T3-L1脂肪细胞的表达情况及其与胰岛素抵抗的关系。方法用3种不同浓度的地塞米松(10、100、1000nmol/L)建立3种不同程度的脂肪细胞胰岛素抵抗模型(分别称为模型组1、模型组2、模型组3),同时设立空白对照组。采用2-脱氧-3H-D-葡萄糖摄入法检测葡萄糖的摄入情况,以葡萄糖摄入减少的百分比反映胰岛素抵抗程度;RT-PCR技术检测各组SAA mRNA的表达,ELISA检测SAA蛋白的表达。结果各组基础状态下葡萄糖的摄取率无明显差异(P>0.05);胰岛素刺激后模型组1、模型组2、模型组3的葡萄糖摄取率分别比对照组减少了15%(P<0.05)、40%(P<0.01)、55%(P<0.01);SAA mRNA的表达量分别是对照组的2.5(P<0.01)、3.33(P<0.01)、4.08倍(P<0.01);SAA蛋白表达量分别是对照组的2.05(P<0.05)、3.13(P<0.01)、4.23倍(P<0.01);相关分析显示3T3-L1脂肪细胞SAA mRNA的表达量(r=0.773,P<0.01)和蛋白表达量(r=0.832,P<0.01)与胰岛素抵抗程度均呈正相关。结论采用地塞米松干预3T3-L1脂肪细胞可成功建立胰岛素抵抗模型;脂源性炎症因子SAA与胰岛素抵抗密切相关,它可能是胰岛素抵抗的一个标记物。

Objective To study the relationship between the expression of serum amyloid A （SAA） and insulin resistance in 3T3-L 1 adipocytes. Methods 3T3 -L 1 adipocytes were incubated with different concentrations of dexamethasone （10, 100, and 1000 nmoFL） for 48 h to establish cell models of insulin resistance at different resistant levels （models 1, 2, and 3, respectively）. The degree of insulin resistance of 3T3-L1 adipocytes was assayed by 2-deoxy- [^3H]-D-glucose uptake. Semiquantitative RT-PCR was performed for quantification of SAA mRNA expression. SAA concentrations in the culture medium were determined by ELISA. Result Dexamethasorte did not affect the basal gtucose transport （P〉0.05）. Insulin-stimulated glucose uptake was significantly decreased by 15% （P〈0.05）, 40% （P〈0.01）, and 55% （P〈0.01） in models 1, 2, and 3 in comparison with the untreated group, respectively; the expressions of SAA mRNA were upregnlated by 2.5 （P〈0.01）, 3.33 （P〈0.01）, and 4.08 folds （P〈0.01） and SAA concentrations increased by 2.05, 3.13, and 4.23 folds, respectively. The expressions of SAA mRNA were positively correlated to the degree of insulin resistance （r=0.773, P〈0.01） and SAA concentration （r=0.832, P〈0.0 1）. Conclusion A cell model of insulin resistance has been established in 3T3-LI adipocytes by dexarnethasone exposure. SAA is closely associated with insulin resistance and may serve as a marker of insulin resistance.