己酮可可碱对非酒精性脂肪性肝炎大鼠肝脏核因子-κB信号通路及胰岛素抵抗的干预作用

目的观察己酮可可碱对非酒精性脂肪性肝炎大鼠肝脏核因子-kB（NF—kB）信号通路及胰岛素受体底物（IRS）-1、IRS-2和葡萄糖转运子2（GLUT2）表达的影响。方法24只SD大鼠高脂饮食饲养4周后，随机分为模型组和干预组，于实验第24周处死，并设普通饮食饲养大鼠6只作对照组。电泳迁移率分析检测肝脏NF—kB活性，Westernblot检测肿瘤坏死因子（TNF）α和KB抑制蛋白α（IkBα）表达，逆转录聚合酶链反应检测肝脏IRS—1、IRS12和GLUT2mRNA表达。结果与对照组相比，模型组肝脏NF-kB和TNFα显著增加，IkBα显著降低，伴IRS-2表达显著增加；与模型组相比，干预组NF—kB和TNFα显著降低，IkBα有所增高，而IRS-2表达显著减少；肝脏IRS—1和GLUT2表达在3组之间差异均无统计学意义。结论己酮可可碱可能通过影响肝脏NF—kB信号通路和增加肝细胞IRS-2表达，从而有助于改善非酒精性脂肪性肝炎大鼠肝脏胰岛素抵抗。

Effects of pentoxifylline on hepatic nuclear factor-kappa B signaling pathway and insulin resistance in nonalcoholic steatohepatitis rats induced by fat-rich diet

OBJECTIVE: To explore the effects of pentoxifylline (PTX) on nuclear factor-kappa B (NF-kB) signaling pathway, insulin receptor substrates (IRSs) and glucose transporter 2 (GLUT2) expressions in livers in a rat model of nonalcoholic steatohepatitis (NASH). METHODS: Rats fed a fat-rich diet for 4 weeks were randomly allocated into two groups; the model group rats (n = 12) were fed a high-fat diet alone and the PTX group rats (n = 12) were fed a high-fat diet plus PTX (100 mg x kg(-1)/d(-1)) in drinking water. Meanwhile, rats (n = 6) fed a standard diet from the start served as controls. All the rats were sacrificed at the end of the 24th week. Hepatic NF-kappaB binding activity was measured by electrophoretic mobility shift assay (EMSA). The expression of tumor necrosis factor (TNF) alpha and inhibitor kappaB (IkappaBalpha) proteins in livers were determined by Western blot. Messenger RNA of IRS-1, IRS-2 and GLUT2 expressions were examined by RT-PCR. RESULTS: NF-kappaB binding activity was higher in the model group than that in the controls, while it was lower in the PTX group compared with that in the model group. The expression of TNFalpha protein was markedly increased in the model group (vs. the control group) but decreased in the PTX group (vs. the model group). The expression of IkappaBaalpha protein was decreased in the model group (vs. the control group) but increased in the PTX group (vs. the model group) to a certain extent. IRS-2 mRNA expression was markedly increased in the model group, and significantly decreased in the PTX group when compared with the model group (P less than 0.01). CONCLUSIONS: PTX could influence NF-kappaB signaling pathway and IRS expression in livers of NASH rats, which might be involved in the improvement of hepatic insulin resistance.