Mechanism Of LBP On Regulating Adipocyte Function By PPARγ

Objective: Due to the economic development and the lifestyle changed, the incidence of obesity increases rapidly in the world, and PRC’s obesity rate in 2014 is 11%. Obesity is a metabolic syndrome, causes the type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease and high blood pressure etc, threatened the human health. Many researches focused on the mechanism of obesity recently, peroxisome proliferator-activated receptor(peroxisome proliferator activated receptors gamma, PPARγ) were found playing a key role in the generation and development of obesity. PPARγ belongs to the ligand-activated nuclear receptor transcription factor, plays an important role in the fat generation, metabolism of lipids and the regulation of energy metabolism. lycium barbarum polysaccharides(LBP) is a chinese traditional drug, our previous morphological observation of LBP with the high fat diet-induced mouse model, found LBP reduced the size of fat cells significantly. Therefore, we assumed that LBP ameliorates obesity induced by high fat through the PPARγ and the possible molecular mechanism.Methods: 1.we established the C57BL/6 mouse models of obesity by the high-fat diet successfully, selected the 40 C57BL/6 male mice(age: 6-8 weeks, weight: 18-20 g),and divided them into 4 groups randomly: normal diet group, high fat diet group, 100 mg/kg LBP+high fat diet group,and 200 mg/kg LBP+high fat diet group. then we monitor the change of weight, intake of the diet and water,lasts 24 weeks, collect serum and abdomen white adipose tissue after fasting for 8 hours, detect the physiological and biochemical parameters of obesity-related by enzyme-linked immunosorbent assay(ELISA), fluorescence PCR(q RT-PCR) methods. 2. We established the 3T3-L1 adipocytes model of obesity incubated by the palmitic acid(PA) successfully. The 3T3-L1 pre-adipocytes line were differentiated into mature 3T3-L1 line,then incubated the mature 3T3-L1 line with the 100 μg/m L, 300 μg/m L, 600 μg/m L, 900 μg/m L LBP for 24 hours, detect the expression of the phosphatidylinositol 3 kinase(PI3K), phosphorylation of PI3K(P-PI3K), protein kinase b(PKB/AKT), phosphorylated AKT(P-AKT), c-Jun N-terminal kinase(JNK) and phosphorylation of JNK(P-JNK), and phosphorylation of PPARγ(P-PPARγ) expression by the western blotting. 3. In the 3T3-L1 adipocytes obesity model, 10 μM LY294002(PI3K/AKT signaling pathway inhibitor) incubated for 1 hour; 20 μM SP600125(JNK signaling pathway inhibitors)incubate for 1 hour; 10 μM rosiglitazone(PPARγ agonist-rosiglitazone) incubated for 12 hours, collected the whole cell protein respectively, then detects the expression of P-AKT/AKT, P-JNK/JNK, P-PPARγ/PPARγ by the western blotting. AKT and JNK small interfering RNA(small interfere RNA, si RNA) transfected 3T3-L1 adipocytes obesity model for 48 hours, detect the expression of P-AKT/AKT, P-JNK/JNK, P-PPARγ/PPARγ by the western blotting.Results: 1. The obesity-related parameters of the C57BL/6 mouse model and 3T3-L1 adipocytes model decreased significantly after the LBP incubation. 2. In the 3T3-L1 adipocytes model, P-PPARγ and P-AKT expression decreased, P-JNK expression expression increased, after the LBP incubation, p-PPARγ and p-AKT expression inceased, p-JNK expression decreased. 3. In the 3T3-L1 adipocytes obesity model, after LY294002(PI3K/AKT signaling pathway inhibitor) incubation or AKT small interfering RNA transfection, the expression of AKT and p-PPARγ decreased; after SP600125(JNK signaling pathway inhibitors) or JNK si RNA transfection,the expression of JNK and p-PPARγ decreased.Conclusion: 1. LBP ameliorated obesity. 2. LBP increased the expression of P-PPARγ by activating PI3K/AKT pathway, then inhibiting the phosphorylation of JNK expression. 3. LBP ameliorated obesity by inhibiting the activity of PPAR-γ, decreasing fat production.