The Impacts Of Diet Adaptation On Adiponectin Expression In Diet-induced Obesity Rats

Part 1 Establishing rat obese modelObjective: Establish rat obese model using high-fat-fed for 3 months. Methods: Eightty male Sprague-Dawley rats, 2 months of age. After a week for adaptation, rats were randomized assigned to two dietary groups: (1) normal diet group (n = 10), fed with standard chow(fat provide 17.2% of the energize); (2) high-fat diet group,( n = 70), fed with 82% normal diet supplemented with 18% grease (fat provide 42.9% of the energize). All rats were subjected to alternate 12-h periods of dark and light (lights on 6:00 a.m.–6:00 p.m.). Temperature and humidity were maintained at 23 ?C and 40–60%. Rats were housed three per cage and given free access to water and diet. The amount of daily fodder was equal, and all the rats were fed at 8:00 a.m everyday. Food consumption was measured by subtracting the remained food before feeding. There are no differents between the diet of control group and the high-fat diet group beside fat and starch. The total period for establishing the obesity model was 12 weeks. The body weight of each rat was recorded once a week. After fasting diet for 10 hours at the end of 0,4,8,12 week, took the tail blood, separated serum which were kept in the -80℃freezer for the mensuration of serology index.Results: After 12 weeks, with the standard of average weight add 1.4 times of standard-deviation, there are 34 rats from the high-fat diet rats were considerd as obesity rats and were divided to four groups to get into the next stage. The achievement ratio was 48.6%.Conclusions: High-fat diet that contain 18% grease, 42.9% of the energize provided by fat could be usde to establishing rat obese model.Part2 The accommodation of diet regulation on the adiponetin level of ratsObjective: After reducing the contents of fat, changing the composition of fatty acid, cutting-down the contents of energy those in the diet for rats, we observed the express level of adiponectin, the serun adiponectin level and other correlated index. And explored the effect of adiponectin level on obesity and saccharum-fat metabolism, tried to find the dietary pattern that better to prevent obesity,diabetes,cardiovascular disease and so on.Methods: The obesity rats were divide into four groups: high-fat diet group, lower-fat group, adjust-fat group and limited-energy group. Rats were housed three per cage and given free access to water and diet beside the limited-energy group which were housed one per cage. Food consumption was measured by subtracting the remained food before feeding. Took the intake of control group as a standard, the diet of limited-energy group was as 80% as the intake of the control group. The part that been cut down was starch, other nutritional ingredients were completely the same with other groups. After fasting for 10 hours at the end of 16th week, took the tail blood at 9 AM, separated serum, kept in the -80℃freezer for the mensuration of serology index. Took fats of internal organs, liver, renal, spleen, aorta, apex cordis and all kept in the -80℃freezer for the mensuration of serology index and RT-PCR.Results:1.After 8 weeks'dietary pattern adjustment, both the body weight and the content of internal organs fat of the limited-energy group were lower than those of the high-fat diet group and other adjusting groups(p < 0.05), but closer to the control group. The lower-fat group and the adjust-fat group are both amelioration than high-fat group, but not statistically significant(p > 0.05).2. Reduced the contents of fat, changed the composition of fatty acid, cut-down the contents of energy could inhibit the content of serum TG, TC, LDL-C, HDL-C, blood-sugar and higher the blood-trypsin. The effect of limited-energy group is more significant than the other two groups(p < 0.05).3. The level of adiponectin of the control group and the high-fat diet group showed a lysis tendency, but the lower-fat group, the adjust-fat group and the limited-energy group had a opposite manifest. The effect of limited-energy group was more significant than the other two groups(p < 0.05).4.The result of RT-PCR showed that after 8 weeks'adjustment, the adiponectin express level of the fatty tissue of the lower-fat group and the limited-energy group were significant higher than that of the high-fat group and the adjust-fat group(p < 0.05); But the adiponectin express level of the adjust-fat group was lower than that of the high-fat group, the reason needs to be further empirical study.Conclusions:l Reduced the contents of fat, changed the composition of fatty acid, cut-down the contents of energy can elevate the express level of adiponectin of fat tissue and the density of serun adiponectin of obesity rats, improve the TG,TC,HDL-C,LDL-C,blood sugar,insulin level. The group which adopt combination intervention study of lower-fat + adjust-fat + limited-energy had the most significant improving. The finding shed light on the prevent for obesity and other correlated disease.