Dissertation > Excellent graduate degree dissertation topics show

Effects of Dietary Ratios of n-3 to n-6 Polyunsaturated Fatty Acids on Lipid Metabolism of SD Rats

Author: JiaManXue
Tutor: WangFeng
School: Fourth Military Medical University
Course: Nutrition and Food Hygiene
Keywords: n-3/n-6 polyunsaturated fatty acids (PUFA) Adenylate -dependent protein kinase ( of AMPK ) Peroxisome proliferator-activated receptor γ (PPAR-γ) Neuropeptide Y (NPY) Appetite Real-time fluorescent RT-PCR
CLC: R151
Type: Master's thesis
Year: 2009
Downloads: 184
Quote: 0
Read: Download Dissertation

Abstract

Many animal experiments and clinical investigations have confirmed that hyperlipidemia and is closely related to many chronic metabolic diseases. The essential fatty acids contained in animal and vegetable fats and oils have an important physiological role in maintaining human health. Dietary multi-unsaturated fatty acids (Polyunsaturated fatty acids PUFA) has the role of lipid metabolism, wherein the efficacy of n-3 and n-6 ??type. However, a single intake of some kind of vegetable oil fatty acid composition mode are unreasonable. Currently, the United Nations Food and Agriculture Organization (FAO) 5 to 10:1 fatty acid n-6/n-3 nutrients recommended than value. In today's diet conditions, n-6PUFAs generally excessive, while the n-3PUFAs serious shortage, however, the academic community has a reasonable ratio of the two is still controversial. Studies have shown that, PUFA play to improve blood lipid, at least in part, through the activation of AMP-activated protein kinase (AMP-activated protein kinase AMPK). AMPK role of substrate including hydroxymethyl glutaryl single acyl coenzyme A (HMGR), acetyl coenzyme A carboxylase (ACC), hormone-sensitive lipase (HSL), glycogen synthetase. AMPK is a major regulatory factors of eating behavior. Hypothalamic neurons AMPK on appetite mechanism is still not well understood. Hypothalamic AMPK regulation of appetite at least through the regulation of neuropeptide Y (NPY) and AGRP and promote appetite factor expression. AMPK activity changes by the intracellular concentration of malonyl coenzyme A and carnitine esters acyl transferase enzyme 1 (CPT-1) activity affects appetite. The proportion of the PUFA of the present experimental design a using the recommended ratio, and the other to use a higher proportion of n-3, in order to correct the status of dietary n-6 excessive. The experiment by dietary ratio of SD rats of different fatty acids, to get reasonable n-3/n-6 fatty acid ratio, and explore PUFA whether AMPK pathway through the peripheral and central role in regulating systemic nutrition metabolism with PUFA food prevention and treatment of high cholesterol, cardiovascular disease provide a scientific basis. Adaptive feeding experimental method 58 clean male Sprague-Dawley (SD) rats one week after tail vein blood measured serum total cholesterol (TC) levels were randomly divided into six groups, namely: the blank control group 9 hyperlipidemia control group nine, 10 fat 1:1 group, 1:5 group 10 fat, low-fat 1:1 10, 1:5 group of 10 low-fat. Experimental period of 45d. The rat single cage feeding, drinking deionized water, based on the weight given to the different needs of feed, the six diets were the basal diet; high fat diet; n-3/n-6 the 1:1 high fat diet (n-3 linolenic acid oil, containing 60% alpha linolenic acid; n-6 in the borage oil, containing 20% ??gamma linolenic acid, 40% linoleic acid); n-3/n-6 1:5 high fat diet; n . -3/n-6 1:1 low-fat feed; n-3/n-6 1:5 low-fat diet. The rats were recorded daily food intake and body weight changes. Respectively, the day before the experiment, the experiment 15d, 30d tail vein blood serum was separated and 37 ° C water bath for 30min at 4 000 r / min centrifugal separation of serum kit detection TG, TC, LDL-C, HDL-C levels . Section 45d of the experiment, fasted for 12h, rats were sacrificed after ether anesthesia, the liver and the hypothalamus organizations quickly saline flush, filter paper for drying, frozen in liquid nitrogen prepared measured mRNA and protein expression. To take subcutaneous fat, subperitoneal fat, epididymal adipose perirenal fat were weighed to calculate the ratio of lipid bodies. The real-time RT-PCR quantitative detection of PPAR-γ in the liver of AMPK-α2 mRNA in hypothalamic NPY, AMPK-α2 mRNA expression levels. Western blot analysis of the liver and the hypothalamus AMPKα and phosphorylated AMPKα protein concentration. The experimental results section 45d of the experiments on the effect of different n-3/n-6 ratio of fatty acids on serum lipids levels, TC, TG, LDL-C water of the high-fat group were higher than those in the other five groups, there were significant differences (P lt; 0.05); 45 days blank group and high-fat 1:1 group than in the high-fat group HDL-C have significant differences (P lt; 0.05). Visible PUFA significant improvement in the levels of serum lipids. After 2 different n-3/n-6 ratio of fatty acids on body weight and fat ratio experiment 45d, have increased in each group of animal body weight. The high-fat group compared with the other five groups weight differences were statistically significant (P lt; 0.05). Fat 1:5 and low-fat 1:5 subcutaneous fat and high-fat group, the differences were statistically significant (P lt; 0.05). Add PUFA 4 peritoneal fat, epididymal adipose, the perirenal fat ratio and fat body than compared with the high-fat group, the differences were statistically significant (P lt; 0.05). PUFA can reduce the the rats weight and body fat, in particular, reduce visceral fat accumulation. Different n-3/n-6 ratio of fatty acids on food intake in rats: the 12 days of the experiment the, of PUFA four proportional rats appetite significantly reduced, compared with the high-fat group and blank group differences with statistical significance, (P lt; 0.05) and duration of action lasting. Showed that rats PUFA can reduce appetite. Different n-3/n-6 ratio of fatty acids affect rat AMPK-α2 and PPAR-γ and NPY mRNA expression: 45 days given different ratio of fatty acids in dietary Add PUFA ratio of the four group liver AMPK-α2 PPAR-γmRNA expression the water average compared with the blank control group declined, and the high-fat group had significantly elevated compared expression, and the difference was statistically significant (P lt; 0.05) PUFA can enhance liver AMPK The expression of PPAR-γmRNA. Group of four proportion hypothalamic AMPK-α2 NPYmRNA expression with the high-fat group and blank group were significantly reduced, and the difference was statistically significant (P lt; 0.05), fat 1:5 group with low-fat: Group 1 was significantly different (P lt; 0.05), PUFA can inhibit the hypothalamus of AMPK and NPYmRNA of expression. Different n-3/n-6 ratio of fatty acids in the rat AMPK-α and phosphorylation of AMPK protein expression: given a different ratio of fatty acids in dietary 45d, four proportion of group (high fat 1:1, high fat 1:5, low fat 1:1, compared to the low-fat 1:5) liver AMPK-α subunit total protein expression levels were blank group significantly increased AMPK activity significantly decreased in high-fat group, the proportion of fat two groups the The activity was lower than the control group and the proportion of low-fat two groups, and most low-fat 1:1 group AMPK-α activity, PUFA can enhance liver the AMPK protein activity expression. However, the hypothalamus, the group of four PUFA proportion hypothalamic AMPK-α subunit total protein levels than those in a significant reduction in the control group; compared to the high-fat group and the blank group no significant difference in the expression. The group of four PUFA proportion hypothalamic AMPK-α phosphorylation activity were significantly lower than the control group and the high-fat group. Low-fat 1:1 group and low-fat 1:5 group AMPK-α phosphorylation expression level 1:1 groups was significantly lower than the high-fat and high fat 1:5 AMPK activity of the high-fat group compared with the blank group the expression no significant difference. PUFA can inhibit the expression of hypothalamic AMPK protein activity. Experimental conclusions the n-3/n-6 1:1 and two 1:5 ratio of PUFA dietary were improved rats with high blood cholesterol and reduce fat accumulation by increasing liver AMPK expression and PPAR-γ gene expression of fatty acid oxidation and inhibition of hypothalamic appetite-related genes NPY and AMPK expression. However, due to changes in fat metabolism is the result of the interaction of a variety of factors, to clarify the mechanism of PUFA affect fat metabolism of obese rats, also need further in-depth study.

Related Dissertations

CLC: > Medicine, health > Preventive Medicine,Health > Nutrition, hygiene,food hygiene > Nutrition
© 2012 www.DissertationTopic.Net Mobile