2型糖尿病大鼠模型抵抗素基因表达与胰岛素敏感指数的相关性

背景:抵抗素作为一种蛋白质激素,具有直接对抗胰岛素的作用,其可能是肥胖者易发2型糖尿病的关键分子.目的:构建2型糖尿病大鼠模型并观察大鼠抵抗素的基因表达与胰岛素敏感指数的关系,观察罗格列酮对抵抗素基因表达的影响.设计:随机对照,动物实验.单位:郑州大学第一附属医院老年病科.材料:选用健康雌性Wistar大鼠30只,鼠龄2个月,购自华中科技大学同济医学院动物中心.实验用普通饲料由华中科技大学同济医学院动物中心提供,总热量为14..8 J/g(质量分数:蛋白质0.2,碳水化合物0.61,脂肪0.17);高脂饲料由普通饲料加蔗糖、炼猪油、鸡蛋、奶粉混合而成,总热量为20.083 J/g(蛋白质0.09,碳水化合物0.51,脂肪0.38).大鼠抵抗素及β-actin引物由北京赛百盛公司合成.方法:实验于2006-10/2007-10在郑州大学第一附属医院完成.实验过程中对动物的处置符合动物伦理学要求.适应性喂养大鼠2周后,随机分为普通饲料组8只和高脂饲料组22只.高脂饲料组大鼠尾静脉注射链脲佐菌素25 mg/kg,注射后第2人开始给予高脂饮食;普通饲料组给予柠檬酸钠一柠檬酸缓冲液1 mL/kg尾静脉注射,继续普通饲料喂养.高脂饲料喂养12周后有15只大鼠符合2型糖尿病模型标准,被随机分为罗格列酮组8只和模型组7只,前组用罗格列酮2 mg/(kg·d)灌胃,后组用蒸馏水8 mL/(kg·d)灌胃;普通饲料组灌胃等量蒸馏水,干预4周.主要观察指标:应用葡萄糖氧化酶法测定血糖;采用磁性分离酶联免疫法测定胰岛素;采用酶法测定血清三酰甘油和总胆固醇.计算胰岛素敏感指数(1/空腹血糖×空腹胰岛素).用反转录-聚合酶链反应检测大网膜脂肪组织抵抗素mRNA的表达.应用Spearman相关分析和多元逐步回归分析显示抵抗素基因与胰岛素敏感指数的关系.结果:造模成功15只和对照组大鼠8只进入结果分析.①大网膜脂肪组织抵抗素基因表达(A值):模型组为0.27±0.031,明显高于普通饲料和罗格列酮组(0.15±0.018和0.20±0.024,P<0.01).②Spearman相关分析和多元逐步回归分析结果:抵抗素基因与空腹血糖、空腹胰岛素和胰岛素敏感指数分别呈正相关(r=0.271、0.283和0.323,P<0.01);多元逐步回归分析显示,胰岛素敏感指数对抵抗素基因的作用最显著(R2=0.081).结论:2型糖尿病大鼠抵抗素基因表达升高,且与胰岛素敏感指数相关;罗格列酮可逆转此状况.

Correlation between resistin gene expression and insulin sensitivity index in type 2 diabetic rat models

BACKGROUND: Resistin decreases insulin's action. Therefore might be a key molecule in the pathogenesis of type 2 diabetes mellitus in obese subjects.OBJECTIVE: To investigate the correlation of resistin gone expression and insulin sensitivity index (ISI) in type 2 diabetic rat models, and to explore the effect of rosiglitazone on resistin gone expression in a rat diabetic model.DESIGN: Randomized controlled animal study.SETTING: Department of Geratology, the First Affiliated Hospital of Zbengzhou University.MATERIALS: Thirty 2-month-old healthy female Wistar rats were provided by Animal Center of Tongji Medical College,Huazhong University of Science and Technology. Common diets were provided by Animal Center of Tongji Medical College, Huazhong University of Science and Technology, and the gross calorific value was 14.88 J/g (mass fraction: 0.2protein, 0.61 carbohydrate, 0.17 fat); furthermore, high-fat diets were mixed with common diets, saccharobiose, rendered lard, egg, and mild powder, and the gross calorific value was 20.083 J/g (mass fraction: 0.09 protein, 0.51 carbohydrate, 0.38fat). Resistin and β -actin were synthesized in Beijing Salbaisheng Company.METHODS: This study was performed in the First Affiliated Hospital of Zhengzhou University from October 2006 to October 2007. The experimental for animal manipulation conforms to criteria of the university's ethnic committee. Two weeks after adaptability, rats were randomly divided into normal chew group (n=8) and high-fat diet group (n=22). Rats in the high-fat diet group underwent vena caudalis injection with streptozotoein (25 mg/kg), and two days later they were continued fed with high-fat diet. For normal chew group rats were injected with sodium citrate-citrate buffer solution (1 mL/kg) and continued normal chew. After 12 weeks, 15 rats in the high-fat diet group were hyperglycemic and were randomly divided into rosiglitazone (n=8) and high-fat diet diabetic group (n=7). Rats were lavaged with rosiglitazone (2 mg/kg/d) in the rosiglitazone group and with distilled water (8 mL/kg/d) in high-fat diet diabetic group; for normal chew group rats were lavaged with the same volume of distilled water. Rats were studied for four successive weeks.MAIN OUTCOME MEASURES: Fasting serum glucose was measured with glucose oxidase method; insulin by magnetic separation enzyme linked immunosorbent assay; triglyceride and total cholesterol levels by enzymic enzymatic method; ISI was calculated as [1/(fasting serum glucose × fasting insulin)]; resistin mRNA expression in greater omental adipose tissue was examined by RT-PCR; correlation between resistin gene and ISI analyzed by Spearman correlation and multivariate stepwise regression.RESULTS: Fifteen high-fat diet rats and eight normal chew rats were included in the final analysis. Resistin gene expression in the greater omental adipose tissue (A value) was 0.27±0.031 in the high-fat diet diabetic group (0.15±0.018) in the normal chew group, and (0.20±0.024) in rosiglitazone group (P < 0.01). Spearman correlation analysis and multiple stepwise regression analysis showed that resistin gene expression was positively correlated with fasting serum glucose (r=0.271, P < 0.01), fasting insulin (r=0.283, P < 0.01), and ISI (r =0.323, P < 0.01), apparent effects of resistin gene expression on ISI was 0.081.CONCLUSION: High-fat diet and diabetes increases resistin gene expression and rosiglitazone ameliorate its expression.The expression of resistin is correlated with ISI.