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

Jun WANG; Hao WANG; Zhen GUO; Xiaoyu ZHANG; Songyi QU; Tianzhen ZHENG

ABSTRACT

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.