Preventive Mechanism Of Mogroside On Obese Mice Induced By High-Fat Diet

Obesity has become a major threat to global human health.In recent years,there has been an emerging focus on the potential impact of obesity and related metabolic diseases caused by artificial sweeteners that have been widely used in food precession.Therefore,the active development of new plant-derived functional natural sweeteners may provide a new direction for reducing obesity and improving related metabolic disorders.In this thesis,we investigated the preventive effects and preventive mechanisms of natural sweetener mogroside extracted from rape Momordica grosvenori(Luo Han Guo)on obesity and insulin resistance induced by high-fat diet in mice.At the same time,the effect of artificial sweetener aspartame was compared with that of mogroside under the condition of equal sweetness.In this study,the mice were divided into the following five groups(n=10/group): 1.low-fat diet(LFD)tap water;2.high-fat diet(HFD)tap water;3.HFD+5 mg/ml Luo Han fruit extract(HFD+LSG);4.HFD 10 mg/ml+Luo Han fruit extract(HFD+HSG);5.HFD+1 mg/ml Aspartame water Solution(HFD+Asp).During 18 weeks of preventive intervention,diet,drinking water and body weight were recorded weekly.In the final two weeks,glucose tolerance test(GTT)and insulin tolerance test(ITT)were performed on mice in each group.After that,serum,subcutaneous fat(SAT),epididymal fat(EAT)and perirenal fat(PRF),were collected to detect parameters such as,insulin resistance and adipose tissue inflammation.The main results are as follows:(1)Mogroside has the certain inhibitory effect on obesity gains.The changes of body weight,diet and visceral fat content of mice in each group within 18 weeks were counted.The results showed that compared with high fat diet or aspartame treatment,both LSG and HSG treatment could inhibit body weight gain,the weight of both epididymal adipose tissue and perirenal adipose tissue characterized by reduced volume and number of adipocytes.In particular,mice in LSG group even showed better performances than those in HSG group.(2)Mogroside can improve systemic glucose tolerance and insulin sensitivity.Consistent with inhibition of weight gain,Fasting blood glucose,fasting plasma insulin concentration,insulin resistance index(HOMA-IR),the glucose tolerance(GTT)and insulin resistance(ITT)in HFD+LSG or HFD+HSG groups displayed better performances than those in HFD+ASP group.Taken together,these observations indicated that,contrary to aspartame,mogroside might possess superiority in the prevention of metabolic adverse resulted from high-fat diet.(3)Mogroside can increase browning of white adipose tissue.The food efficiency ratio(FER)of mice in HFD+LSG group and HFD+HSG group showed a decreasing trend,indicating that the body weight conversion rate of food decrease and the consumption increase.Furthermore,the expression of UCP1 gene in subcutaneous fat from mice in HFD+LSG and HFD+HSG group was significantly up-regulated,while the gene UCP1 in HFD group and HFD+ASP group was significantly inhibited.It is suggested that mogroside may increase heat production and promote energy consumption by inducing the browning of subcutaneous white fat.(4)Mogroside can reduce adipose tissue inflammation.The related inflammatory factors in epididymal adipose tissue of mice were detected by RT-PCT,IHC and Western blot respectively.The results showed that the expression of inflammatory factors such as Leptin,MCP-1 and TNF-? was significantly down-regulated in HFD+LSG and HFD+HSG groups.Also,the recruitment and infiltration of macrophages was significantly reduced in epididymal adipose tissue.To sum up,the results of long-term intervention of mogroside extract in mice fed with high-fat diet showed that mogroside showed better anti-obesity effect than aspartame,and the main mechanism of improvement of obesity and insulin resistance are from two aspects: inducing browning of white adipose tissue and reducing adipose tissue inflammation.In addition,the content of sweet glycosides in Luo Han fruit water extract was determined.And the results showed that Mogroside V(M-V)was the main sweet glycoside.Therefore,the M-V component may exert its anti-obesogenic functionality as the main effective component of Luo Han fruit..