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米非司酮对胰岛素抵抗的HepG2细胞的作用及其机制

Effects and mechanisms of mifepristone on insulin-resistant HepG 2 cells

  • 摘要: 以糖消耗量为评价指标,筛选由不同浓度的胰岛素(Ins 0,1,0.1,0.01 μmol/L)与地塞米松单用或合用24 h诱导的HepG2细胞最佳胰岛素抵抗模型,考察该抵抗模型持续时间,并探讨糖皮质激素受体拮抗剂米非司酮对胰岛素抵抗细胞的作用及机制。建立最佳抵抗模型后给予米非司酮或比格列酮作用24 h,测定细胞的糖消耗量、胞内葡萄糖、糖原、ATP及游离脂肪酸含量,半定量RT-PCR法测定胰岛素受体(InsR)-mRNA和糖皮质激素受体(GR)-mRNA的表达。结果显示胰岛素(0.1 μmol/L)和地塞米松(0.3 μmol/L)合用24 h组为最佳胰岛素抵抗模型组,且其抵抗状态至少可以持续36 h;模型组细胞糖消耗量、胞内糖、糖原、ATP含量以及InsR-mRNA表达显著低于正常细胞,而 FFA浓度与GR-mRNA表达明显增高;0.2 mmol/L的比格列酮与200 μmol/L及20 μmol/L的米非司酮可明显改善胰岛素抵抗细胞,而2 μmol/L的米非司酮对胰岛素抵抗细胞无影响。结果表明:米非司酮通过调节糖脂代谢及胰岛素受体和糖皮质激素受体表达水平而改善胰岛素抵抗。

     

    Abstract: HepG2 cells were pre-incubated with insulin (Ins 0,1,0.1,0.01 μmol/L) and dexamethasone (Dex 0,3,0.3,0.03 μmol/L) alone or together for 24 h to induce insulin resistance(IR)in vitro,the resistant level was estimated by glucose consumption,the optimal model of insulin resitance was chosen,and at the same time its lasting time of resistance was determined.In order to investigate the effects and mechanisms of mifepristone on insulin-resistant HepG2cells induced by insulin and dexamethasone,mifepristone and pioglitazone were administered 24 h after the optimal model of insulin-resistant HepG2 cells was established.The glucose consumption,intracellular concentrations of glucose,glycogen,ATP,and free fatty acid (FFA) in each group were detected.The expression of InsR-mRNA and GR-mRNA was detected by semi-quantitative reverse transcription and polymerase chain reaction (SqRT-PCR).Results revealed that pretreatment with insulin (0.1 μmol/L) and dexamethasone (0.3 μmol/L) for 24 h caused optimal insulin resistance of HepG2 cells which lasted for 36 h.Compared with control group,the glucose consumption,intracellular glucose,glycogen,ATP contents and the level of InsR-mRNA in model cells decreased while FFAs concentrations and GR-mRNA increased.However,the tendency of insulin- resistant HepG2 cells was obviously attenuated by pioglitazone at the concentration of 0.2 mmol/L and mifepristone at 200 μmol/L and 20 μmol/L while mifepristone at 2 μmol/L had no effect on insulin-resistant cells.The findings indicated that mifepristone at 200 μmol/L and 20 μmol/L improved the insulin resistance via modulating intracellular glucolipid metabolism and the expression of InsR-mRNA and GR-mRNA.

     

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