Changes of fibroblast growth factor-21 and its receptors in high-fat diet fed apoE~(-/-) mice / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the effects of high-fat diet induced insulin resistance on fibroblast growth factor-21 (FGF-21) and its receptors expression in ApoE~(-/-) mice. Method Male ApoE~(-/-) mice were randomly divided into normal-chow group(NF,n=20)and high-fat fed group(HF,n=20) and fed for 16 weeks. The insulin sensitivity and glucose-lipid metabolism in awake mice were evaluated by hyperinsulinemic-euglycemic clamp technique combined with 3-[~3H]-glucose as a tracer. The Mrna expressions of FGF-21,β-klotho, and FGFR1-4 were measured by quantitative real-time PCR. FGF-21 protein levels were determined by Western blot. Results Fasting blood glucose, plasma insulin and free fatty acids, triglycerides, free fatty acids, and cholesterols were significantly elevated in HF group compared with NF group(all P<0.01). During the steady-state of clamp, plasma insulin was significantly higher in HF group than that in NF group(P<0.01), and glucose infusion rate was also significantly decreased(P<0.01). At the end of insulin clamp, glucose disappearance rate was significantly lower in HF group than that in NF groups(P<0.01). Hepatic glucose production in NF group was suppressed by 70% ,while in HF group it was suppressed by 51%. The FGF-21 Mrna expressions of hepatic and adipose tissues in HF group were significantly increased compared with NF group(both P<0.01), and β-klotho Mrna expressions increased(P<0. 05). In hepatic and adipose tissues, FGFRI, Mrna expressions were higher in HF group than those in NF group(both P<0.01) ,and FGFR3 Mrna increased(P<0.01 and P<0.05, respectively). In hepatic tissue,FGFR4 Mrna levels were significantly up-regulated in HF group(P<0. 05). Plasma FGF-21 levels were elevated in HF group compared with NF group(P<0.01) ,and FGF-21 protein expressions of hepatic and adipose tissues were also increased(both P<0.05). Conclusion FGF-21, β-klotho, FGFR1, and FGFR3 were significantly up-regulated in ApoE~(-/-) mice fed by high-fat diet, and they might be the targets in regulating glucose-lipid metabolism by FGF-21.