| Background and Aims:Glucagon-like peptide-1 (GLP-1) analogues ameliorate non-alcoholic fatty liver disease (no-alcoholic fatty liver disease, NAFLD) by promoting free fat acid (FFA) oxidation, inhibitting hepatic lipid synthesis and hepatic gluconeogenesis, (lipopolysaccharide, LPS) promote the development of NAFLD. It is not clear whether GLP-1 analogues also reduce the LPS induced signal pathway of inflammation, fibrosis and lipid metabolism in HepG2 cell. This study focus on GLP-1 receptor agonists’ effect on LPS induced signal pathway factor of inflammation, fibrosis and lipid metabolism in HepG2 cell. We investigate GLP-1 receptor agonists on liver fat content (LFC) and serum LPS in type 2 diabetes mellitus (T2DM) with NAFLD and compared with metformin and gliclazide MR.Methods:1. HepG2 cell was randomized into three groups:Control group, LPS group and LPS+EX group, Toll-like receptors-4/nuclear factor-kappa B (TLR4/NF-κB) and transform growth factor beta 1(TGF-β1) related proteins in cell were determined by Western Blot.2. Further we added adenosine monophosphate protein kinase (AMPK) inhibitor compound C (CC), HepG2 cell was randomized into five groups:Control group, LPS group, LPS+EX group and LPS+EX+CC group, Proteins of TLR4/NF-κB and TGF-β1 were estimated by western Blot and gene levels of inflammation and lipid metabolism signal pathway factors were measured by RT-PCR.3.90 type 2 diabetes (T2DM) patients with NAFLD were randomized into three groups:Group A (liraglutide,30):0.6mg per day in the first week,1.2mg per day in the second week,1.8mg per day in the following 22 weeks, Group B (gliclazide MR,30):the initial dose is 30-60mg per day, the dose is adjusted by the fasting blood glucose; and Group C (metformin,30):0.25g three times per day in the fist week,0.5g g three times per day in the second week, 1g twice a day in the following 22 weeks. The LFC after the 24Weeks’ treatment were measured.Results:1. Western Blot:Compared with the control group, the protein levels of TLR4, Myeloid differentiation primary response gene 88 (MyD88), Nuclear Factor-kappa B (NF-κBp65), TGF-β1 and inhibitor of nuclear factor kappa-B kinase subunit beta (P-Ikκβ) were significantly increased in LPS group (p<0.01) After the treatment of Exenatide, the protein levels of TLR4, MyD88, NF-κBp65, P-Ikkβ and TGF-β1 were significantly decreased compared with the LPS group(p<0.01-0.05), TLR4 levels even lowered than the control group(p<0.05). The TLR4 levels of the LPS+ EX+CC group was higher than the LPS+EX group(p<0.05), and the levels of TGF-β1 protein of both the LPS+EX+CC group significantly increased compared with LPS+EX group (p<0.01).2. RT-PCR:Compared with the Control group, the mRNA levels of TLR4, Tumor necrosis factor-alpha (TNF-a), Sterol regulatory element-binding protein lc (SREBP-lc), Acetyl-coA carboxylase (ACC) and Fatty acid synthase (FAS) in LPS group significant increased(p<0.01). Compare with the LPS group, TLR4, TNF-α, SREBP-1c, FAS and ACC mRNA levels in the LPS+EX group significantly decreased(p<0.01-0.05); The SREBP-lc levels of LPS+EX+CC group increased compared with LPS+EX group (p<0.05).3. Tnterim statistics showed 41patients finished 24 weeks treatment, the LFC of all three groups declined (p<0.01),there were no significant difference among the A B, C groups after the treatment, and the LFC decline of group A is much more than group B(p<0.05); weight and body mass index (BMI) of group A and group C were significantly decreased contrast to OW (P< 0.05), and the decline value of weight and BMI in group A higher than group B; Waist circumference and Waist to hip ratio of group A were significantly decreased contrast to OW, and there were downward trend in group C and upward trend in group B, and changes of waistline were significant different between group A and group B; Glycosylated hemoglobin Ale (HbAlc) and serum LPS of all three groups decreased (P<0.01), blood lipid disorders improved, and 30 minutes,60 minutes and 120 minutes blood glucose levels of group A in standard meal lowered than group B and 120 minutes blood glucose levels of group A lowered than group C.Conclusions:1. LPS might active the pathway of inflammation and lipid metabolism of Hep-G2 cells.2. GLP-1 analogues inhibited LPS induced inflammation lipid metabolism pathway in Hep-G2 cells,3. GLP-1 analogues’s effect on LPS-induced inflammation lipid metabolism pathway factors in Hep-G2 cells partly through of AMPK and PI3K/AKT4. GLP-1 analogues, biguanide drugs and sulfonylurea drugs used alone all could effectively reduced LFC the in T2DM patients with NAFLD, and along with the serum LPS decreased; Compared with sulfonylurea drugs, the GLP-1 analogues reduced LFC more effectively, and GLP-1 analogues control blood sugar more efficiently than biguanide and sulfonylurea drugs. GLP-1 analogues reduce more weight and waistline than sulfonylureas, and all these drugs improved dyslipidemia. |
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