中华鳖卵对胰岛素抵抗大鼠糖代谢的影响

目的研究中华鳖卵对胰岛素抵抗模型大鼠糖代谢的影响。方法雄性SD大鼠以高脂饲料喂养4个月建立胰岛素抵抗模型,按照体重和空腹胰岛素水平分为模型对照组(insulin resistant control,IRC)和3个中华鳖卵实验组,另选以基础饲料喂养4个月的健康雄性SD大鼠作为空白对照组(negative control,NC)。实验组大鼠以灌胃方式给予不同剂量(0.5、1.5和4.5 g/kg bw)的中华鳖卵冻干粉(Chinese soft-shell turtle egg,TEP),IRC和NC组给予等体积溶剂灌胃。实验期间IRC及TEP各组继续喂饲高脂饲料,NC组喂饲基础饲料,实验周期8 w。于实验结束时进行口服糖耐量实验(OGTT),检测空腹血糖、胰岛素,计算胰岛素敏感指数,RT-PCR方法检测肝脏中胰岛素受体、胰岛素受体底物-1 mRNA的表达,并观察胰岛β细胞的超微结构改变。结果高脂饲料喂养4个月后大鼠空腹胰岛素水平升高,胰岛素敏感指数下降,成功建立胰岛素抵抗模型。实验结束时,与IRC组比较,各剂量TEP组大鼠空腹胰岛素水平明显下降,而胰岛素敏感指数明显升高;1.5和4.5g/kg bw TEP组大鼠空腹血糖水平明显降低,4.5g/kg bw TEP组大鼠OGTT中0.5h血糖水平和血糖曲线下面积明显降低;TEP各剂量组肝脏胰岛素受体和胰岛素受体底物-1 mRNA表达水平明显增高,同时胰岛β细胞的超微结构得到明显改善。结论 TEP对高脂饲料诱导的胰岛素抵抗大鼠糖代谢紊乱具有明显的改善作用。

EFFECTS OF CHINESE SOFT-SHELL TURTLE EGG ON BLOOD GLUCOSE METABOLISM IN HYPERINSULINEMIA RATS

Objective To observe the effects of Chinese soft-shell turtle egg powder(TEP) on blood glucose metabolism in rats with insulin resistance(IR).Method Male SD rats were fed with high fat diet for 4 mo to establish IR model.Thirty two IR rats were divided into four groups according to body weight and serum insulin level,namely insulin resistance control(IRC) group and 3 Chinese soft-shell turtle egg(TEP) groups,8 rats in each group.Another 8 healthy male rats fed with basic diet were used as negative control(NC).The rats in TEP groups were treated i.g.with TEP at the dose of 0.5,1.5 and 4.5g/kg bw respectively for 8 w,while the rats in IRC and NC groups were treated with solvent in the same manner.During the test period,the rats in IRC and TEP groups were fed with high fat diet sequentially,while the rats in NC group were fed with basic diet.Fasting serum glucose(FBG),insulin(FINS) were assayed and insulin sensitive index(ISI) was calculated before and after TEP treatment respectively.Oral glucose tolerance test(OGTT),mRNA expression detection of insulin receptor(INR) and insulin receptor substrate-1(IRS-1) in liver and islet cell ultrastructure observation were carried out at the end of the experiment.Results After 8 w treatment,compared with IRC group,FINS decreased obviously in all three TEP treated groups and FBG lowered obviously in 1.5 and 4.5g/kg bw TEP groups,while ISI increased significantly.Moreover,serum glucose level at 0.5h and the area under curve in OGTT were evidently lower in 4.5g/kg bw TEP group.Besides,the expression of INR and IRS-1 were up-regulated in all three TEP treated groups.Finally,electron microscopy showed that islet ultrastructure impairment resulted from high fat diet was improved evidently by 4.5 g/kg bw TEP.Conclusion TEP was effective in improving glucose metabolic dysfunction in high fat diet induced insulin-resistant rats.