The Effect Of Probiotic-fermented Soymilk Hypolipidemic And Ameliotating Liver Injury In Mice Fed A High-fat Diet

Background: Recent 10 years, cardiovascular diseases(CVDs) represented by hyperlipidemia has occupied the top cause of death. Cardiovascular and cerebrovascular diseases have threatened seriously to human health. Varying degrees of side effects would be produced after taking them, so it’s urgent to develop safe, healthy and effective hypolipidemic functional foods and strategies to modulate lipid levels for preventing the development of CVDs. Research have found that probiotic-fermented soymilk play a role of modulating blood lipids. However, fewer researches reported the effect of probiotic-fermented soymilk on liver injury induced by high fat diet. The objective of this study was to investigate the effects of probiotic-fermented soymilk on lipid metabolism and high-fat diet-induced hepatic injury in mice.Methods: The in vitro cholesterol removal ability of ten strains separated from pickle was measured. The acid-resistance, bile salt-resistance and in vitro cholesterol removal ability of L. casei, L. plantarum and L. helveticus were measured. C57BL/6N mice were randomly divided into 7 groups: normal chow group, high fat group, L. casei fermented soymilk intervention group, L. plantarum fermented soymilk intervention group, L. helveticus fermented soymilk intervention group, three probiotic-fermented soymilk intervention group and non-fermented soymilk intervention group. After 7 weeks treatments, serum and liver lipid levels were measured, liver histopathological changes were observed and to explore the mechanism of hypolipidemic and ameliorating liver injury of probiotic-fermented soymilk through leptin and related factors of lipid metabolism pathways.Results: 1. A strain of highly efficient cholesterol removal ability was screened, which was identified as L. plantarum.2. In vitro cholesterol removal ability of L. casei, L. plantarum and L. helveticus were 43.14%, 46.27% and 40.53%, respectively. They had good properties of acid and bile salt tolerance.3. Probiotic-fermented soymilk treatment reduced abdominal and perirenal fat indexes by 26.98% and 46.41%, respectively. Probiotic-fermented soymilk significantly reduced serum and liver total cholesterol(TC), triglycerides(TG), low density lipoprotein(LDL) and malondialdehyde(MDA) levels and elevated serum high density lipoprotein(HDL) level, which showed that probiotic-fermented soymilk can reduced higher lipid level induced by high-fat diet to prevent and alleviate atherosclerosis and cardiovascular disease.4. Probiotic-fermented soymilk significantly fell by 5.16% in liver index, reduced serum and liver alanine aminotransferase(ALT), aspartate aminotransaminase(AST), serum lipopolysaccharide(LPS) and tumor necrosis factor(TNF-α) levels, improved significantly accumulation of fat in liver to ameliorate liver injury induced by high-fat diet.5. Probiotic-fermented soymilk increased leptin and triacylglycerol hydrolase(TGH) levels. Probiotic-fermented soymilk has hypolipidemic effect and ameliorates high-fat diet-induced liver injury maybe through up-regulating TGH expression and down-regulating SREBP-1 and DGAT expressions via leptin pathway.Conclusion: Probiotic contain L. casei, L. plantarum and L. helveticus fermented soymilk was effective in hypolipidemic and preventing or ameliorating high-fat diet-induced liver injury. The molecular mechanism was to modulate lipid synthesis and metabolism via leptin pathway.