Oxidative Stress And Lipid Metabolism Mechanism Of Germinated Brown Rice On Rats And LO2Cells

Objective:This research studied the effectiveness of germinated brown rice and its components on hypercholesterolemia-induced rats and LO2liver cells against oxidative capacity and lipid metabolism, and provided experimental bases and insights on germinated brown rice functional-products.Methods:In vivo:thirty SD rats were randomly divided into five groups A、B、C、D、 and E. groups A and B were, respectively, fed by normal diet and high lipid diet for8weeks; while groups C、D、and E were fed with high lipid diet for4weeks and then, respectively, fed with12.5%,25%and50%of germinating brown rice ad libitum for four weeks.In vitro:LO2liver cells were cultured for24h using the following treatments:(A) control treatment,(B)30ppm palmitic acid (PA),(C)30ppm PA+50ppm y-amino butyric acid (GABA),(D)30ppm PA+50ppm oryzanol,(E)30ppm PA+50ppm GABA+50ppm oryzanol. The effects of GABA and Oryzanol on PA treated LO2cells were evaluated by measuring and analysing the changes on intracellular cholesterol (TC, FC, CE), antioxidant capacity (MDA, SOD, GSH-PX and TAOC), and the expression t of PPAR-γ、LXR-α、 SREBP1and CYP7A1.Results:(1) Compared with the control group, consumption of hypercholesterolemic diet can significantly increase the level of serum TC、AST and ALT (p<0.05). Meanwhile, grossly visible, the liver of hypercholesterolemia-induced rats showed steatosis, hepatomegaly, paleness, and brittle texture. T-AOC and T-SOD were significantly decreased, oxidative damaging product MDA was increased (p<0.05). To a certain extent germinated brown rice can improve liver T-AOC, T-SOD enzyme activity, they show significantly different (p<0.05) results with the hypercholesterolemic group. Group D and E showed significantly lower MDA compared with the group B. TC of GBR supplemented groups were significantly lower than hypercholesterolemic group. Group E treatment significantly reduced the serum TG, AST and ALT levels (p<0.05).(2) In this study, treatment of PA significantly increased the level of TC and CE, significantly reduced intracellular GSH-PX, T-SOD, and CAT activity, induced more serious intracellular oxidative damages, and decreased the expression of PPAR-y and CYP7A1in LO2cells, up-regulated the expression of SREBP1and LXR-a. Groups C. D, and E treatments significantly improved the intracellular accumulation of lipid droplets, lower intracellular FC, TC and CE level, except the level of CE in group C which has not significant difference with group B. The germinated brown rice active components GAB A and oryzanol significantly improved cell activity of antioxidant enzymes thus improving the antioxidant capacity of cells, except group E where use of GABA together with oryzanol did not increase CAT and did not reduce the MDA lever in LO2cells. GABA and oryzanol treated groups showed upregulated SREBP1and LXR-a expressions, significantly higher level of PPAR-y than PA treated group B. Oryzanol have a better effect on up-regulating the expression of PPAR-yConclusion:Germinated brown rice can improve the antioxidant capacity of the body, regulate the body’s cholesterol and triglyceride levels, prevent lipid metabolism disorders, reduce the damage caused by bad cholesterol and protect the liver, affect liver cells through regulation of nuclear receptor proteins related to lipid metabolism, and show positive effects in prevent fatty liver and other lipid metabolism-related diseases.