氧化苦参碱对胰岛素抵抗小鼠肝脂质转运酶的作用

Effect of oxymatrine on hepatic lipid transport in insulin-resistant of mice

目的研究氧化苦参碱对胰岛素抵抗小鼠肝脂质转运酶的作用。方法将C57BL/6J小鼠设为对照组。以高脂喂养载脂蛋白E基因敲除(Apo E-/-)小鼠16周,建立胰岛素抵抗小鼠模型。按照体重将Apo E-/-胰岛素抵抗小鼠随机分为4组:模型组、小、中、大3个剂量实验组(25,50,100mg·kg^(-1)氧化苦参碱),连续灌胃8周。进行高胰岛素-正葡萄糖钳夹实验;以实时定量荧光聚合酶链反应和免疫印迹法检测肝组织脂质转运酶相关基因表达。结果与对照组比较,在模型组小鼠的肝中,三酰甘油(TG)、胆固醇(TC)和脂肪酸(FFA)含量均明显升高,差异均有统计学意义(均P<0.05)。在模型组小鼠的血清中,空腹血糖(FBG)、TC、TG、FFA水平均明显升高而胰岛素(FINS)降低;模型组的小鼠葡萄糖输注率(GIR)值为(16.46±1.62)m U·kg^(-1)·min^(-1),肝脂蛋白酯酶(LPL)、脂肪酸转位酶(FAT/CD36)mRNA表达分别为2.21±0.35,3.61±0.42,肉毒碱棕榈酰基转移酶1(CPT1)、过氧化物酶体增殖物激活受体α(PPARα)mRNA表达分别为0.28±0.04,0.23±0.04,LPL、FAT/CD36蛋白分别为0.93±0.15,0.72±0.08,CPT1、PPARα蛋白表达分别为0.31±0.05和0.22±0.04,与对照组比较差异均有统计学意义(均P<0.05)。给药后,实验组小鼠肝TG、TC和FFA含量降低,体重、血糖、血脂降低,胰岛素水平均降低。中、大2个剂量实验组GIR值分别为20.13±1.84,21.33±2.26;这2组的LPL mRNA表达分别为1.60±0.21,1.19±0.14,这2组的FAT/CD36 mRNA表达分别为1.63±0.19,1.78±0.24,这2组的CPT1表达分别为0.87±0.12,0.90±0.15,这2组的PPARα表达分别为0.68±0.11,0.55±0.08,这2组的LPL蛋白表达分别为0.61±0.08,0.45±0.06,这2组的FAT/CD36蛋白表达分别为0.33±0.04,0.36±0.05,这2组的CPT1分别为0.96±0.13,0.99±0.17,这2组的PPARα分别为0.65±0.10,0.71±0.11,与模型组比较差异均有统计学意义(均P<0.05)。结论氧化苦参碱能通过调节肝脂质转运酶,改善小鼠胰岛素抵抗。

Objective To investigate the effect of oxymatrine on hepatic lipid transport in insulin resistant of mice.Methods C57BL/6J mice were selected as control group.Apolipoprotein E gene knockout（Apo E-/-） mice were fed with high-fat diet for 16 weeks to establish the model of insulin resistance,which were randomly divided into model group,low,middle and high dose experimental groups.The experimental groups were given a gavage of 25,50,100 mg·kg-1oxymatrine,respectively.All groups were continuously administrated for 8 weeks.Hyperinsulinemic-euglycemic clamp test were measured.The expression levels of lipid transport enzyme regulated genes in the hepatic were examined byreal-time fluorescence quantitative PCR and Western-blot.Results Compared with the control group,the contents of triglyceride（TG）,cholesterol（TC） and fatty acid（FFA） in the liver of model group significantly increased.Compared with the control group,serum fasting blood glucose（FBG）,TC,TG and FFA levels significantly increased.Fasting insulin（FINS） were lower.Glucose infusion rate（GIR）（16.46 ± 1.62） m U·kg-1·min-1in model group was significantly lower than that control group.Lipoprotein lipase（LPL） and fatty acid translocase（FAT/CD36）mRNA expression in model group increased,which were 2.21 ± 0.35 and 3.61 ± 0.42.Carnitine palmitoyl transferase1（CPT1） and peroxisome proliferator-activated receptor α（PPARα） mRNA expression in model group decreased,which were 0.28 ± 0.04 and 0.23 ± 0.04.The protein expressions of LPL,FAT/CD36（0.93 ± 0.15,0.72 ± 0.08）in model group increased,while CPT1,PPARα（0.31 ± 0.05,0.22 ± 0.04） in model group decreased.The differences in above factors were statistically significant（all P 〈 0.05）.After administration,the contents of TG,TC and FFA,blood lipid,insulin levels decreased in the liver of experimental group.The GIR values of middle and high dose experimental groups were 20.13 ± 1.84 and 21.33 ± 2.26 respectively.LPL,FAT/CD36 expression were down-regulation,while CPT1,PPARa expression were up-regulation.The LPL mRNA expressions of middle and high dose experimental groups were 1.60 ± 0.21 and 1.19 ± 0.14 respectively,and the FAT/CD36 mRNA expressions were1.63 ± 0.19 and 1.78 ± 0.24.CPT1 were 0.87 ± 0.12,0.90 ± 0.15,and PPARα were 0.68 ± 0.11,0.55 ± 0.08 respectively.The LPL protein expressions were 0.61 ± 0.08, 0.45 ± 0.06, FAT/CD36 were 0.33 ± 0.04,0.36 ± 0.05,CPT1 were 0.96 ± 0.13,0.99 ± 0.17 and PPARα were 0.65 ± 0.10,0.71 ± 0.11 respectively in the two groups.The differences of above indexes were statistically significant（all P 〈 0.05）.Conclusion Oxymatrine can adjust the lipid transport enzyme in hepatic,thus improving insulin resistance in mice.