Proctor S D, Kelly S E, Stanhope K L, Havel P J, Russell J C
Metabolic and Cardiovascular Diseases Laboratory, Alberta Institute for Human Nutrition, 4-10 Agriculture Forestry Centre, University of Alberta, Edmonton, AB, Canada.
Diabetes Obes Metab. 2007 Jan;9(1):87-95. doi: 10.1111/j.1463-1326.2006.00578.x.
Conjugated linoleic acid (CLA) is a natural constituent of dairy products, specific isomers of which have recently been found to have insulin sensitizing and possible antiobesity actions. Chromium is a micronutrient which, as the picolinate (CrP), has been shown to increase insulin sensitivity in animal models, including the JCR:LA-cp rat. We tested the hypothesis that these agents may have beneficial synergistic effects on the micro- and macrovasculopathy associated with hyperinsulinaemia and early type 2 diabetes.
Insulin-resistant cp/cp rats of the JCR:LA-cp strain were treated with mixed isomers of CLA (1.5% w/w in the chow) and/or CrP at 80 microg/kg/day (expressed as Cr) from 4 weeks of age to 12 weeks of age. Plasma insulin, lipid and adiponectin levels, aortic vascular function, renal function and glomerular sclerosis were assessed.
CLA administration reduced food intake, body weight and fasting insulin in JCR:LA-cp rats. Plasma adiponectin levels were significantly elevated in rats treated with both CLA and CrP. Aortic hypercontractility was reduced and the relaxant response to the nitric oxide-releasing agent acetylcholine (Ach) was increased in CrP-treated rats. Striking reductions were also observed in the level of urinary albumin and the severity of glomerular sclerosis in rats treated specifically with CLA.
CLA and CrP have beneficial effects ameliorating several of the pathophysiologic features of an insulin-resistant rat model. These supplements may be useful adjuncts in the management of patients with the metabolic syndrome and warrant further study.
共轭亚油酸（CLA）是乳制品的天然成分，最近发现其特定异构体具有胰岛素增敏作用及可能的抗肥胖作用。铬是一种微量营养素，作为吡啶甲酸铬（CrP），已在包括JCR:LA-cp大鼠在内的动物模型中显示出可提高胰岛素敏感性。我们检验了这样一个假设，即这些物质可能对与高胰岛素血症和早期2型糖尿病相关的微血管和大血管病变具有有益的协同作用。
JCR:LA-cp品系的胰岛素抵抗cp/cp大鼠从4周龄至12周龄，用CLA的混合异构体（饲料中含1.5% w/w）和/或80微克/千克/天的CrP（以铬计）进行处理。评估血浆胰岛素、脂质和脂联素水平、主动脉血管功能、肾功能和肾小球硬化情况。
给予CLA可降低JCR:LA-cp大鼠的食物摄入量、体重和空腹胰岛素水平。同时接受CLA和CrP处理的大鼠血浆脂联素水平显著升高。CrP处理的大鼠主动脉过度收缩性降低，对释放一氧化氮的药物乙酰胆碱（Ach）的舒张反应增强。单独给予CLA处理的大鼠尿白蛋白水平和肾小球硬化严重程度也显著降低。
CLA和CrP对改善胰岛素抵抗大鼠模型的几种病理生理特征具有有益作用。这些补充剂可能是代谢综合征患者管理中的有用辅助手段，值得进一步研究。
