Experimental Study On Suppressive Effect Of Betaine On High-fat-fed Obese Rats

With the rapid development of economy and high-lipid-diet,overweight and obesity are the most common nutritional disorders in the developing and developed countries,affecting the majority of adults in the world.The prevalence of obesity results to many other diseases.In the developed world,obesity is now the most common disease of childhood and adolescence.Betaine in the livestock feed attractant as agent of lean meat and add in the feed use.However,effects of betaine on boby weight of rats remain unclear.We observed the effects of betaine on weight and serum biochemical index in high-fat-fed obese rats.In order to simulate obesity which is formed by eating high-lipid-diet long time, we made obese model induced by high lipid diet in the experiment,to observe the effect of betaine on high-fat-fed rats and study the mechanism.Body mass,food intake,energy intake and water intake were measured.Blood glouse,serum levels of blood lipids,insulin,glutamate pyruvate transaminase(GPT),glutamate oxalacetate transaminase(GOT),malondialdehyde(MDA),total antioxidant capacity(T-AOC), leptin,resistin,interleukin-6(IL-6),tumor necrosis factor-a(TNF-α)were assayed in experiment.The expression of neuropeptide Y(NPY)mRNA and agouti-related protein(AGRP)mRNA in hypothalamus were detected and the possible mechanisms were preliminarily explored.Fourty-four healthy male SD rats with the body mass of 99.39±2.18g were randomly divided into five groups,namely control group,hyperlipidemia group (HLD),low-dose betaine group(LDB,15mg·kg^-1·d^-1),middle-dose betaine group (MDB,30mg·kg^-1·d^-1),high-dose betaine group(HDB,60 mg·kg^-1·d^-1).Control group and hyperlipidemia group were 10 rats in each group,The three betaine groups were 8 rats in each group.The four groups were fed with high-lipid-diet except control group. The control group was fed with common diet.The control group and hyperlipidemia group were administered 0.9%physiological saline.In three betaine groups were adminstered different dose of betaine.All rats were fed for 56 days.Food intake and water intake were monitored daily and body weight was weighed weekly at set time. At the end of experiment,all rats were fasted for 12 hours and collected blood samples for measuring blood glucose,and serum biochemical index.We used aseptic operation to take hypothalamus and strored it in -80℃to detect the expression of Neuropeptide Y(NPY)mRNA and agouti-related protein(AGRP)mRNA in hypothalamus by Fluorescent Quantitative RT-PCR Technique.SPSS10.0 software was used to analyse the data and the results were expressed as Mean±SD((?)±s).The T-test was used for comparison between two groups.The One-Way analysis of variance(One-Way ANOYA)was used for comparison among the three groups. P＜0.05 represented significant differences.The main results were as follows:(1).Compared with control group,Rats in HLD group displayed increased body mass,energy intake,blood glucose,insulin,high density lipoprotein(HDL),low density lipoprotein(LDL),free fatty acid(FFA),malondialdehyde(MDA),leptin, resistin,interleukin-6(IL-6)and reduced serum total anti-oxidant capacity(T-AOC), The level of Neuropeptide Y(NPY)mRNA and agouti-related protein(AGRP) mRNA in hypothalamus were increased.However,serum level of triglyceride(TG), total cholesterol(TC),glutamate oxalacetate transaminase(GOT)and tumor necrosis factor-a(TNF-a)were no signficant difference.(2).Compared with HDL group,energy intake of seventh week,body mass, blood glucose,malondialdehyde(MDA),triglyceride(TG),free fatty acid(FFA), leptin,resistin,interleukin-6(IL-6)were decreased in HDB group and the level of Neuropeptide Y(NPY)mRNA and agouti-related protein(AGRP)mRNA in hypothalamus were also reduced.Energy intake,insulin,malondialdehyde(MDA) were decreased and total antioxidant capacity(T-AOC)were increased in LDB group. However,high density lipoprotein(HDL),low density lipoprotein(LDL),total cholesterol(TC)and tumor necrosis factor-a(TNF-a)were no signficant difference.The results indicate that betaine can inhibit the weight gain of high-fat-fed rats, regulate serum biochemical index.It effects those index may be by inhibiting the release of peripheral fat factor,increasing the sensitivity of leptin and insulin, eliminating free radicals,enhancing anti-lipid peroxidation and decreasing the expression of NPY and AGRP mRNA in hypothalamus.