构建高脂饮食肥胖大鼠模型体质量及代谢变化与天麻素的干预

背景:天麻素广泛应用于眩晕、头痛及高血压等的辅助治疗,其作为干预物质用于高脂肥胖大鼠的治疗有待评估.目的:构建不同浓度天麻素对高脂饮食性肥胖大鼠模型,观察其对体质量与血清代谢物水平的影响,分析其可能的作用机制.设计:随机对照动物实验.单位:兰州大学基础医学院生理与心理研究所.材料:实验于2007-06/2007-08在兰州大学基础医学院生理与心理研究所和甘肃省新药临床前研究重点实验室完成.选用44只生后1周雄性健康SD大鼠,体质量(99.57±2.13)g,由中科院上海斯莱克实验动物有限公司提供.实验过程中对动物的处置符合动物伦理学标准.基础饲料由苏州双狮实验动物饲料科技有限公司生产,高脂饲料由本实验室自行配制.每100克含基础饲料57.5 g、蛋黄粉11.79g、猪油10g、猪胆盐0.2g、酪蛋白7g、奶粉13g、食盐0.085g、酵母粉0.425g;其中含脂肪22.07g、蛋白质23.7g、碳水化合物39g、热量472.16千卡.纯度为98%的天麻素购自陕西旭煌植物科技开发公司.丙二醛和总抗氧化能力试剂盒均为南京建成生物工程研究所生产.方法:构建天麻素干预高脂饮食性肥胖大鼠模型:①采用基础饲料适应喂养大鼠1周,随机数字表法将大鼠分为正常对照组(n=10)、高脂组(n=10)、高脂 天麻素低、中、高剂量组(每剂量组各8只).②正常对照组喂基础饲料,其它各组均喂高脂饲料.正常对照组和高脂组每天灌胃0.9%生理盐水0.3 mL,高脂 天麻素低、中、高组灌胃同等容量浓度分别为15,30,60mg/(kg·d)的天麻素溶液.③各组大鼠自由进食和饮水,共8周.主要观察指标:①每周末检测各组大鼠体质量.②每日上午定时记录大鼠摄入热量.③高脂喂养结束后,于大鼠股动脉取血测血糖值,同时检测血清丙二醛、总抗氧化能力、胰岛素、游离脂肪酸,血脂、谷丙转氨酶及谷草转氨酶水平,并计算胰岛素敏感指数和抵抗指数.结果:大鼠44只均进入结果分析.①体质量:高脂喂养4～8周高脂组大鼠体质量明显高于正常对照组,差异有显著性意义(P＜0.001).天麻素各剂量组体质量均低于高脂组,差异有显著性意义(P＜0.05～0.01),高脂 天麻素低、中、高剂量组组间比较,差异无显著性意义(P＞0.05),提示天麻素抑制大鼠高脂饮食肥胖无剂量相关性.②摄入热量:高脂组大鼠高于正常对照组,差异有显著性意义(P＜0.01).高脂饮食4周后天麻素各剂量组均低于高脂组,差异有显著性意义(P＜0.05～0.01).③血清丙二醛、总抗氧化能力、谷丙转氨酶、谷草转氨酶水平:与正常对照组相比,高脂组的总抗氧化能力下降,丙二醛水平上升,谷丙转氨酶水平增加,差异均有显著性意义(P＜0.01).与高脂组相比,天麻素低剂量组的总抗氧化能力明显上升,丙二醛水平下降,差异均有显著性意义(P＜0.01).④胰岛素及血糖水平:与正常对照组比较,高脂组大鼠血糖浓度升高,胰岛素敏感指数下降,抵抗指数上升,差异有显著性意义(P＜0.05～0.01).与高脂组比较,天麻素低剂量组血糖浓度降低,胰岛素敏感指数升高,胰岛素抵抗指数降低,差异均有显著性意义(P＜0.05～0.01).⑤游离脂肪酸及血脂水平:与正常对照组比较,高脂组大鼠的游离脂肪酸、低密度脂蛋白胆固醇升高,高密度脂蛋白胆固醇降低,差异有显著性(P＜0.05～0.01).结论:天麻素可抑制高脂饮食性肥胖大鼠体质量增加,作用机理可能与其调节葡萄糖和游离脂肪酸代谢、改善胰岛素抵抗和提高抗氧化能力有关.

Gastrodin in modulating body mass and metabolism in obese rats fed with high-fat diet

BACKGROUND: Gastrodin (GAS) is widely used as adjuvant therapy for vertigo, headache and hypertension. However, it is recently noticed that GAS might be used as an agent for treating obesity.OBJECTIVE: To set up obese rats of high-fat diet to observe the effects of different concentrations of GAS on body mass and serum metabolite levels and to analyze its possible mechanism.DESIGN: A randomized and controlled animal experiment.SETTING: Institute of Physiology and Psychology, School of Basic Medical Science, Lanzhou University.MATERIALS: This study was performed at the Institute of Physiology and Psychology, School of Basic Medical Science, Lanzhou University and Gansu Provincial Key Laboratory of Pre-clinical Study for New Drugs from June to August in 2007. Forty-four healthy one-week-old male SD rats, weighing (99.57±2.13)g, were purchased from Shanghai SILAIKE Laboratory Animal Co., Ltd. Disposal of animals was in accordance with the animal ethics standards. Basic animal feed was provided by Suzhou Shuangshi Laboratory Animal Feed Science and Technology Co., Ltd. High-fat forage were self-made in the authors' laboratory. Each 100 gram of high-fat forage consisted of basic feed (57.5g), egg yolk powder (11.79g), lard (10g), pig bile salt (0.2g), casein (7g), milk power (13g), salt(0.085g), and yeast powder (0.425g), and the 100 gram of high-fat forage contained of fat (22.07g), protein (23.7g), carbohydrate (39g), and quantity of heat (472.16 calorie). GAS (98% in purity) was purchased from Shaanxi Xuhuang Botanical Science & Technology Development Co., Ltd. Malondialdehyde (MDA) and total antioxidative capability (T-AOC) kits were purchased from Jiancheng Bioengineering Institute, Nanjng, Jiangsu Province.MAIN OUTCOME MEASURES: The body mass was measured every seven days. The food intake in each group was monitored in every morning. At the end of the experiment, femoral artery blood samples were collected to determine the blood glucose, the serum levels of MDA, T-AOC, Insulin, free fatty acid (FFA), glutamate-pyruvate transaminase (GPT), glutamic oxalacetic transaminase (GOT) and blood lipid profile. Insulin resistance index (IRI) and insulin sensitivity index (ISI) were calculated as IRI=(FBG×FINS)/22.5 and ISI=1/(FINS×FBG).RESULTS: All 44 rats were included in the final analysis. Body mass: The body mass in the HFFC group was significantly higher than in the NC group from 4th-8th weeks (P＜0.01), while the body mass in GAS groups was lower compared to HFFC group (P＜0.05-0.01). There were no significant differences among the GAS-H, GAS-M, and GAS-L groups (P＞0.05). Therefore, GAS had no dose-dependent relationship in inhibiting the body mass of obese rats of high-fat diet. Caloric intake: The caloric intake was significantly higher in the HFFC group than in the NC group (P＜0.01), and was significantly decreased in GAS group compared to NFFC group from the 4th week (P＜0.05-0.01). Serum levels of MDA, T-AOC, GPT and GOT: The serum level of T-AOC was decreased and that of MDA, GPT were increased significantly in the HFFC group compared with NC group (P＜0.01, P＜0.05). In the GAS-L group, T-AOC, level was significantly increased and MDA level was significantly decreased compared to HFFC group (both P＜0.01). Levels of blood glucose and insulin: In the HFFC group, blood glucose level and IRI were significantly increased, and ISI was obviously decreased compared to NC group (P＜0.05-0.01). In the GAS-L group, blood glucose level and IRI were significantly decreased, and ISI was significantly increased compared to HFFC group (P＜0.05-0.01). FFA and lipoprotein cholesterol levels: In the HFFC group, FFA and low-density lipoprotein cholesterol levels were increased and high-density lipoprotein cholesterol level was decreased compared to NC group (P＜0.05-0.01).CONCLUSION: GAS may play an important role in inhibiting rats' body mass of high-fat diet. The mechanism of action may be related to GAS regulating the metabolism of blood glucose and FFA, improving IRI and elevating T-AOC.