饲料脂肪酸组分与OLETF大鼠胰岛素抵抗的关系

目的研究不同脂肪酸组分与OLETF大鼠胰岛素抵抗的关系。方法以标准饲料喂养40只雄性OLETF大鼠和10只雄性LETO大鼠至14周,随后将40只OLETF大鼠随机均分为4组,分别以标准饲料(A组)、高脂饲料(C组)、高脂富含n-6多不饱和脂肪酸(PUFA)饲料(D组)和高脂富含n-3 PUFA饲料(E组)喂养至24周,同时10只LETO大鼠以标准饲料喂养至24周(作为对照组)。第24周禁食10～14 h后,行口服葡萄糖耐量试验(OGTT),采血测定C肽和免疫反应性胰岛素(IRI)等生化指标。采用正常血糖高胰岛素钳夹技术,评价其胰岛素抵抗状态。结果24周时,对照组大鼠空腹血糖、葡萄糖负荷后120 min血糖和IRI与E组大鼠的差异无显著性(P>0．05),但均明显低于A、C、D组大鼠(P值均<0．05)。各组大鼠间空腹和葡萄糖负荷后120 min的C肽水平的差异均无显著性(P值均>0．05)。对照组和E组大鼠的葡萄糖输注率均明显高于C组和D组大鼠(P值均<0．05)。结论OLETF大鼠较LETO大鼠的血糖水平高,而胰岛素敏感性差。进食高脂富含n-3 PUFA饲料可改善OLETF大鼠的糖代谢和胰岛素抵抗。

Effect of dietary fatty acids on insulin resistance in OLETF rats

Objective To investigate the effect of dietary fatty acids composition on insulin resistance in OLETF rats. Methods Forty 14-week-old male Otsuka Long-Evans Tokushima Fatty(OLETF) rats were ran-domizedly divided into 4 groups(n = 10, each). They were fed with standard diet(A) , high fat diet(C) , high n-6 polyunsaturated fatty acid(PUFA) diet(D) and high n-3 PUFA diet(E), respectively for 10 weeks. Ten male LE-TO rats served as control were fed with standard diet. Oral glucose tolerance tests, C peptide and immunoreactive insulin(IRI) were measured. Hyperinsulinemia clamp was used to evaluate the insulin resistance of the rats. Results At the age of 24-weeks, all OLETF rats except group E had higher levels of fasting plasma glucose, 120' postloading plasma glucose and IRI than those of the control group(P < 0.05). However, the levels of fasting and 120' postloading C peptide were similar in all groups. In addition, LETO and group E rats had higher level of glucose infusion rate than group C and D rats(P < 0.05). Conclusion The OLETF rats had higher levels of plasma glucose and lower insulin sensitivity than the LETO rats, suggesting that diet with high n-3 PUFA may improve glucose metabolism and insulin resistance in OLETF rats.