目的观察c-Jun氨基末端激酶(JNK)信号传导通路在非酒精性脂肪肝病(NAFLD)大鼠中的表达,探讨其在NAFLD发病中的作用。方法雄性SD大鼠64只,随机分为8周对照组、12周对照组、8周高脂组及12周高脂组各16只,对照组喂饲普通饲料,高脂组喂饲高脂饲料。正糖高胰岛素钳夹实验技术检测葡萄糖输注率(GIR),生物化学法检测空腹血糖(FBS)、ALT、AST、甘油三酯(TG)、总胆固醇(TC);放射免疫法检测空腹胰岛素(Fins)、肿瘤坏死因子α(TNFα);分光光度计测定超氧化物歧化酶(SOD)、丙二醛(MDA)、游离脂肪酸(FFAs);Western blot检测肝组织JNK1、胰岛素受体底物1(IRS-1)、胰岛素受体底物1丝氨酸307磷酸化(pIRS-1^Ser307)、蛋白激酶B(PKB)、蛋白激酶B丝氨酸473磷酸化(P—PKB^Ser473)。正态分布数据采用t检验,偏态分布数据采用秩和检验。结果8周高脂组与8周对照组、12周高脂组与12周对照组比较:体质量、肝指数、血清ALT、AST、TG、TC、Fins、FFAs、TNFα、及肝匀浆TG、TC,FFAs、MDA,高脂组(8、12周)均明显高于对照组(8、12周),t值分别为5.90和7.92、9.91和7.42、5.49、4.99和5.31、7.37、2.30和5.86、2.64和3.85、3.86和6.61、10.53、7.07和8.45、T=89.5和T=100、5.20和6.18、11.90和17.83,P值均〈0.05或〈0.01。肝匀浆每毫克蛋白SOD:8周对照组、12周和8周高脂组、12周分别为(21.6±4.0)U、(22.0±3.6)U、(13.0±3.0)U、(10.1±2.2)U,高脂组明显降低,t值分别为4.88、7.92,P值均〈0.01;GIR:8周对照组、12周和8周高脂组、12周分别为(10.8±1.3)mg·kg^-1·min^-1、(10.7±1.2)mg·kg^-1·min^-1、(8.1±1.1)mg·kg^-1·min^-1、(6.3±1.5)mg·kg^-1·min^-1,高脂组明显降低,t值分别为4.52、6.41,P值均〈0.01;高脂组与同期
Objective To investigate the role of c-Jun N-terminal kinase (JNK) signal transduction pathway in the rats of nonalcoholic fatty liver disease (NAFLD). Methods Sixty four Sprague-Dawley rats were randomly divided into four groups: 8-week control group (NGSw), 12-week control group (NG12 w), 8-week high-fat diet (HG8w), and 12-week high-fat diet group (HG12w), with 16 rats in each group. Glucose infusion rate (GIR) was tested by euglycemic hyperinsulinemic clamp;aminotransferase (ALT), aspartate aminotrans- ferase (AST), triglyceride (TG), total cholesterol (TC), free fatty acid (FFAs), fast insulin (Fins), tumor necrosis factor α (TNF α ), superoxide dismutase (SOD) and malondial- dehyde (MDA) were tested by biochemistry automatic analyzer or RIA; The expression of JNK 1, insulin receptor substrate-1 (IRS-1), phospho-IRS-1^Ser307 (p-IRS-1^ Ser307), Protien kinase B (PKB) and phospho-PKB^Ser473 (p- PKB^Ser473) were detected by Western blot. Results Compared to control group, body weight, liver index, serum levels of ALT, AST, TG, TC, Fins, FFAs, TNF α, and TC, TG FFAs, MDA in liver homogenates were increased, while the level of SOD, and GIR were decreased. The expression of JNK1 protein and p-IRS-1^Set307 in liver tissue was up-regulated, while expression of p-PKB^Ser473 was decreased (P 〈 0.05). A positive correlation was found between the expression intensity of JNK1 and IR (Pearson correlation: 0.718, P 〈 0.01). Conclusion The high-fat could induce the expression of JNKI, which in turn modulates the phosphorylation of proteins in the insulin signaling pathway, and induces insulin resistant.