The Inhibition Effect And Mechanism Of Lactobacillius On High Fat Diet-induced Obesity In Mice

Obesity is closely related with high cholesterol, diabetes and other metabolic syndrome, it has become a serious public health problem. Long-term high-fat-diet is an important factor, which can cause obesity. Many treatment of obesity such as weight control drugs and surgery may have some side effects. Therefore, it caused widespread concern in seeking effictive treatment for high-fat-diet induced obesity in the field of food science. Probiotics as live microorganisms which is beneficial to human health is now being used as a treatment of obesity. However, the mechanism of probiotics on treating obesity is unclear and requires further study.In this paper, three Lactobacillus strains were investigated for the inhibition of high-fat-diet induced obesity.We investigate their effects on liver and explore the changes of intestinal microorganisms and adipokines of obese mice to infer the mechanism by probiotics inhibiting obesity.Then, It provide a new idea on control of obesity by developing a special probiotic which can regulating the lipid metabolism and reducing fat deposition.Three Lactobacilli strains Lactobacillus paracasei subsp. Paracasei M5(M5), Lactobacillus paracasei subsp. Paracasei X12(X12), Lactobacillus coryniformis subsp. torquens T3(T3) were administered to high-fat diet induced obesity mice at the dose of 108 CFU/m Land 109CFU/m L.After 6 weeks, M5 and T3 significantly decrease the body weight, body fat index and Lee’s index of mice in a dose-dependent manner.To investigate the level of triglycerides, total cholesterol, HDL and LDL in serm,we find that M5 and T3 can significantly increased the level of TG,TC,LDL but significantly decreased the level of HDL,(P<0.05).Meanwhile, there is no side effects on control-diet mice.In summary, M5 and T3 strains could inhibite the high-fat-diet induced obesity and contol the elevation of blood lipids.The three Lactobacilli prevent the occurenceof non-alcoholic fatty liver by suppressing the double hits of liver lipid accumulation and oxidative stress: HE staining showed that M5 and T3 significantly improved hepatic steatosis in obesity mice.The level of triglyceride in liver indicated that probiotics reduced hepatic TG content in high-fat diet mice and inhibited the accumulation of liver lipids, thereby suppressing the occurrence of fatty liver, which T3 and M5 have significant effect. Long-term high-fat-diet to mice lead to liver oxidative injury, however antioxidant enzymes in liver such as SOD, GSH-Px, CAT were significantly increased in probiotics-fed mice, and in a dose-dependent manner; at the same time the level of liver MDA decreased, T-AOC levels increased(P<0.05); Similar to the above result, T3 and M5 have better effects than X12. Furthermore, the percentage of body fat was negatively correlated with SOD, GSH-Px, CAT and T-AOC, but positively correlated with MDA. The results showed that Lactobacilli T3 and M5 effectively inhibited liver damage, it provide a new idea for the treatment offatty liver caused obesity.Lactobacillus was used to control obesity by regulating the expression of adipokines. ELISA was used to measure the level of leptin and adiponectin in sterm. The results indicated that adiminstration M5 and T3 to mice significantly decreased leptin but increased adipontctin level(P<0.05).RT-PCR was used to investigate the expression of adipokines.The results showed that high fat diet significantly increased the expression of PPAR-γ、TNF-α、FAS, after administration with M5 and T3 for 6 weeks,the expression was significantly decreased,but there is no difference in X12(P<0.05).High-throughput sequencing was used to detect the diversity of intestinal microorganisms. High-fat-diet induced obesity made intestinal microorganisms change in mice, moreover, it reduced the ratio of Firmicutes and Bacteroidetes.After 6 weeks, the diversity of intestinal microorganisims changed.The result of PCo A showed that administration with M5 and T3 made the composition of intestinal microorganisims similar to contol-diet mice.The determination of MDA and T-AOC content in colon tissue indicated that M5 and T3 significantly decreased MDA level but increased T-AOC level(P<0.05). Combinating the results of high-throughput sequencing, we found that fed with M5 and T3 effectively controlled the changes of high-fat-diet induced intestinal redox state and played an important role in mainting the balance of intestinal flora. Probiotics may be through changing the intestinal flora to suppress the formation of obesity in mice.