Yi Ping, Lu Fu-Er, Xu Li-Jun, Chen Guang, Dong Hui, Wang Kai-Fu
Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.
World J Gastroenterol. 2008 Feb 14;14(6):876-83. doi: 10.3748/wjg.14.876.
To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes.
The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-[(3)H]-D-glucose method. The levels of IkB kinase beta (IKKbeta) Ser(181) phosphorylation, insulin receptor substrate-1(IRS-1) Ser(307) phosphorylation, expression of IKKbeta, IRS-1, nuclear transcription factor kappaB p65 (NF-kappaB p65), phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting. The distribution of NF-kappaB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy (CLSM).
After the intervention of palmic acid for 24 h, the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%. Meanwhile, the expression of IRS-1 and PI-3K p85 protein was reduced, while the levels of IKKbeta Ser(181) and IRS-1 Ser(307) phosphorylation, and nuclear translocation of NF-kappaB p65 protein were increased. However, the above indexes, which indicated the existence of insulin resistance, were reversed by berberine although the expression of GLUT4, IKKbeta and total NF-kappaB p65 protein were not changed during this study.
Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine. Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKbeta.
研究小檗碱改善游离脂肪酸（FFAs）诱导的3T3-L1脂肪细胞胰岛素抵抗的作用及分子机制。
通过向培养基中添加棕榈酸（0.5 mmol/L）建立3T3-L1脂肪细胞胰岛素抵抗模型，同时进行小檗碱处理。采用2-脱氧-[(3)H]-D-葡萄糖法测定葡萄糖摄取率。通过蛋白质免疫印迹法检测IkB激酶β（IKKβ）丝氨酸（Ser）181位点磷酸化、胰岛素受体底物-1（IRS-1）丝氨酸307位点磷酸化、IKKβ、IRS-1、核转录因子κB p65（NF-κB p65）、磷脂酰肌醇-3-激酶p85（PI-3K p85）和葡萄糖转运蛋白4（GLUT4）蛋白的表达水平。通过共聚焦激光扫描显微镜（CLSM）观察脂肪细胞内NF-κB p65蛋白的分布。
棕榈酸干预24小时后，3T3-L1脂肪细胞中胰岛素刺激的葡萄糖转运被抑制了67%。同时，IRS-1和PI-3K p85蛋白的表达降低，而IKKβ丝氨酸181位点和IRS-1丝氨酸307位点的磷酸化水平以及NF-κB p65蛋白的核转位增加。然而，尽管在本研究中GLUT4、IKKβ和总NF-κB p65蛋白的表达没有变化，但小檗碱逆转了上述表明存在胰岛素抵抗的指标。
小檗碱可改善FFAs诱导的3T3-L1脂肪细胞胰岛素抵抗。小檗碱通过靶向IKKβ逆转3T3-L1脂肪细胞中游离脂肪酸诱导的胰岛素抵抗。
