| Nowadays,high-fat dietary patterns and unhealthy lifestyles lead to obesity and obesity-related chronic metabolism diseases.The prevalence is rising worldwide and has become an urgent global health problem.Increasing evidence verified that the pathogenesis of obesity and related complications were associated with gut microbiota dysbiosis.So regulating gut microbiota has be considered as a potential target for the prevention or treatment of obesity and related chronic diseases.Meanwhile,dietary intervention,including use of some probiotics or the functional components such as polyphenols,polysaccharides and flavonoid of plant,is the most basic and effective therapy to alleviate obesity and its complications by modulating the gut microbiota.Seabuckthorn(Hippopha? rhamnoides),as a functional plant homologous to medicine and food,is crammed with a variety of nutrients and biological substances,such as polyphenols,flavonoids,organic acids,vitamin C,polysaccharides,unsaturated fatty acids,and various amino acids required by the human body.Several studies have reported that seabuckthorn extract has the positive effect of lowering plasma cholesterol,increasing intestinal probiotics,improving lipid metabolism enzyme activity,enhancing antioxidant ability,and reducing the incidence of chronic diseases.Seabuckthorn is consumed mainly in the form of the related processing products,such as juice,seed oi,and extraction,but studies using seabuckthorn itself are limited.Considering the loss of nutritional components during processing,the study of whole seabuckthorn is more meaningful.Seabuckthorn freeze-dried powder(SFP)is made by low-temperature freeze-drying technology,which retains the most of useful nutrients such as peel,pulp,fruit oil,and seed oil,and still has strong biological efficacy.Thus,this study investigated the effects of seabuckthorn freeze-dried powder as a dietary intervention on obesity,obesity-associatedlipid metabolism disorders and the modulation of gut microbiota in high-fat diet-induced mice.The main contents and results of this study are as follows:(1)Effects of seabuckthorn freeze-dried powder protects against obesity in high-fat diet-induced mice.A total of 50 six-week-old male C57BL/6 were housed individually under suitable environment conditions.After acclimation for two weeks,the abnormal mice were knockout and the rest of mice were housed individually and randomly allocated into 5 groups(n = 8): normal control diet group(NC),high-fat diet group(HFD)and low-,middle-,high-dose seabuckthorn freeze-dried powder groups(LSFP,MSFP,HSFP)gavaged administration with a dose of 1.0,2.0,4.0 mg/(g.d.body weight)the homogenates of seabuckthorn freeze-dried powder,respectively).The mice in the NC group were fed with normal diet,while the remaining groups were fed with high-fat diet for ten weeks.During the experiment,the food intake and condition of the mice were recorded and the body weight was monitored weekly.After the experiment,liver weight,fat weight,serum total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C),and hepatic TC and TG were measured,and histopathological section of fat and liver were observed by H&E staining.The results showed that the body weight,Lee’s index,adipose tissue weight,liver weight and the levels of serum TC,TG,LDL-C and hepatic TC and TG of mice in the HFD group were significantly increased compared to the NC group(p < 0.05),indicating that the high-fat diet could lead to obesity and lipid metabolism disorders.Whereas,administration seabuckthorn freeze-dried powder could significantly suppress the increase of these basic physiological indicators in high-fat diet-induced mice(p < 0.05).And the results of H&E staining showed that the area of adipose tissue cells in the HFD group were significantly enlarged(p < 0.05),and more lipid droplets appeared in the liver compared with the NC group mice.After the intervention of seabuckthorn freeze-dried powder,it can inhibit the increase of the area of adipose tissue cells and ameliorate the formation of lipiddroplet in hepatic tissues.So,we concluded that intake of a certain amount seabuckthorn freeze-dried powder could protect against obesity and alleviate obesity-related lipid metabolism disorders caused by a high-fat diet in mice,and it was more effectively reversed in high-fat diet mice administered high dose of seabuckthorn freeze-dried powder compared to those administered low or middle dose of seabuckthorn freeze-dried powder groups..(2)Effects of seabuckthorn freeze-dried powder on lipids metabolic related mechanisms in high-fat diet-induced mice.To further explore the potential molecular mechanisms of seabuckthorn freeze-dried powder on amelioration of obesity and lipid metabolism disorders in high-fat diet-induced mice,we quantified the metabolism-related genes m RNA expression levels by real-time quantitative PCR analysis,mainly including encoding lipogenic and store genes(PPAR-γ,FAS,ACC and SCD1),encoding lipolysis(HSL and C/EBP-α)in the epididymal adipose tissue,and encoding lipogenic genes(SREBP-1c,PPAR-γ,FAS and ACC)and encoding fatty acid oxidation genes(PPAR-α,CPT-1 and ACOX)in the hepatic tissue.Our results demonstrated that treatment with seabuckthorn freeze-dried powder could down-regulate the m RNA relative expression of SREBP-1c,PPAR-γ,ACC,and SCD1,and up-regulateng the m RNA relative expression of HSL,CPT-1,and ACOX to effectively reduce fat accumulation and attenuate obesity and lipids metabolisms disorders in high-fat diet-induced mice.(3)Effects of seabuckthorn freeze-dried powder on gut microbiota and short-chain fatty acids in high-fat diet-induced mice.More and more evidences showed that the gut microbiota played an important role in the development of obesity and lipids metabolism disorders in mice induced by high-fat diet.To identify the relationship between the modulation of gut microbiota and the improvement of obesity and lipid metabolism disorders through the seabuckthorn freeze-dried powder intervention,so the relative abundance at phylum,family,and genus level was investigated.Results showed that the intake of seabuckthorn freeze-driedpowder could regulated the composition of gut microbiota,such as increasing the ratio of Firmicutes/Bacteroidetes,decreasing relative abundance of harmful bacteria(Desulfovibrio),and increasing relative abundance of beneficial bacteria(Akkermansia and Bacteroides).Correlation analysis results showed that,the abundance of beneficial bacteria(Akkermansia and Bacteroides)had a positive correlation with genes encoding lipolysis and a negative correlation with genes encoding lipid lipogenesis and store.The harmful bacteria(Desulfovibrio)were just the opposite.Besides,changes in gut microbiota had obvious effects in the secretion of main metabolites-short-chain fatty acids(SCFAs),such as acetic acid,propionic acid and butyric acid,especially propionic acid.In summary,seabuckthorn freeze-dried powder could prevent high-fat diet-induced obesity and related lipid metabolism disorders,and the beneficial effects most likely by regulating the composition and structure of gut microbiota.Therefore,seabuckthorn freeze-dried powder may be used as a potential prebiotic or functional food to meliorate obesity and obesity-related metabolic syndromes. |
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