| IntroductionThe incidence of obesity has increased obviously accompany with the development of economy and the change of human living form. Now,obesity has been thought of as a crucial risk factor of hypertension , coronary heart disease, noninsulin dependent diabetes mellitus and so on. It influence health and living quality of human being severely. Therefore, it has an important meaning to investigate the mechanism of obesity and to prevent the occuring and developing of obesity.There are many studies about the reason or influencing factors ofobesity, among them that the relationship of neuropeptide Y ( NPY) and obesity is a hotspot. NPY, an important determinant in obesity onset and the most powerful orexigenic agent discovered to date,appears to play a central role in the control of feeding behavior. The purpose of the following experiment was to investigate the change of serum NPY of dietary - obese rats, the inflence bringed by NPY receptor antagonist and provide a new idea for prevention and cure of obesity.ObjectiveThe purposes of this experiment are:1. Assessing levels of serum NPY, lipid, blood sugar changes induced by high - fat diet.2. Investigating if NPY - Y5 receptor antagonist can reduce fat accumulation of dietary - obese rats, improve abnormality of lipid metabolism induced by obesity and reduce complications related to obesity.3. Assessing if NPY - Y5 receptor antagonist can be developed as a new way for prevention and cure of obesity.Materials and MethodsAnimal and Diets. Thirty - five female Wistar rats weighting 170 10g were obtained from the Animal Department of China Medical University. Animals were individually housed in cages in a temperature -controlled room(22 5 ) with a 12 - hour light - dark cycle. Animals were given free access to diets and water over the duration of the study.Experimental procedure. All animals were initially fed a standard diet for 1 week. Then, rats were fasted for 24h before blood were sampled from the eye vein. Six days after the blood samples were obtained, 28 rats were given a high -fat diet to induce obesity,the other 7 rats were given a standard diet as control. The composition of diets is listed on Table 1. All rats were maintained on their allotted diet for 10 weeks. At every weekend in this period,body weights were measured. At the end of 10th week,blood were sampled. After 6 days,the obese rats were divided into control group, low - dose group, high - dose group based on body weight gain randomly. They were injected intrap-eritoneally with vehicle (10% DMSO) ,NPY - Y5 receptor antagonist CGP71683A 5mg/ml or CGP71683A lOmg/ml ( the menstruum is 10% DMSO) respectively. In the 28 days injection period,food intakes were measured every day and body weights were measured every three days. At the end of experiment, all animals were killed by decap-itation after sampled blood. Abdominal fat pads ( perirenal, mesenter-ic) were excised, weighted and frozen. All blood samples were centri-fuged and the serum was stored at - SOT!.Assays. Serum NPY concentrations were assays with radioimmu-noassay kits. Serum total cholesterol (TC) , triglyceride (TG) , blood sugar levels were assays with enzymatic kits.Statistical method. All values are expressed as means ?SE. Data were analyzed across multiple groups by one - way ANOVA, followed by a Duncans new multiple range test or Students t - test when appropriate.Results1. Changes of high - fat diet group and control group rats induced by high - fat diet1. 1 Body weightsAfter given lOwk of high - fat diet,body weights of high - fat diet group rats were significantly greater than control group(P <0. 05).1.2 Serum NPY levelsAt the end of 10wk,the NPY levels of high - fat diet group rats were significantly higher than control group ( P <0.05 ) .1.3 Serum lipid and blood sugar levelsAfter lOwk of high - fat diet, the TG levels of high - fat diet group rats were significantly increased compared with control group ( P <0.05). The TC and blood sugar levels... |
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