慢性炎症加重肥胖小鼠肝糖代谢紊乱机制初探

Chronic inflammation aggravates hepatic glucose metabolism disorder in obese mice

目的:探讨慢性炎症是否可加剧肥胖状态小鼠糖代谢紊乱,及是否影响肝脏糖异生及相关机制。方法:野生C57BL/6J小鼠随机分为正常饮食组、高脂饮食组、高脂饮食合并炎症组(高脂饮食加酪蛋白注射组)。小鼠巨噬细胞标志物F4/80免疫组化染色检测肝脏巨噬细胞浸润情况,实时荧光定量PCR检测单核细胞趋化蛋白-1(Mcp1),糖异生相关基因葡萄糖-6-磷酸酶(G-6-pase)和磷酸烯醇式丙酮酸(Pepck)m RNA相对表达量,过碘酸-希夫染色和蒽酮法检测肝脏糖原含量,蛋白免疫印迹法检测肝脏组织叉头框蛋白O1(Fox O1),蛋白激酶B(Akt)及其磷酸化蛋白表达。结果:高脂饮食加酪蛋白注射组较高脂饮食组肝脏组织炎症明显升高(P=0.000),且空腹血糖及胰岛素耐量曲线下面积均明显升高(P=0.040,P=0.025),肝脏糖原积聚亦明显增加(P=0.000),肝糖异生相关基因G-6-pase、Pepck m RNA表达明显升高(P=0.001,P=0.001),而肝脏Akt及Fox O1蛋白磷酸化程度均明显下降(P=0.021,P=0.003)。高脂饮食组较正常饮食组肝脏Akt、Fox O1蛋白磷酸化降低,糖异生基因表达增加,但血糖仍维持在正常水平。结论:慢性炎症可进一步加剧肥胖小鼠肝糖代谢紊乱,诱导肥胖小鼠高血糖。

Objective ：To investigate whether inflammation plays a role in accelerating glucose metabolism disorder in obese mice and whether the mechanism is regulated by liver gluconeogenesis. Methods：The C57BL/6J mice were randomly divided into normal chaw diet group,high fat diet group,high fat diet with chronic inflammation group（high fat diet with casein injection group）. The macrophage infiltration in the liver was detected by F4/80 Staining. The mRNA relative expression levels of Mcpl, G-6-pase and Pepck were ex- amined using real-time quantitative PCR. The liver ~lvcogen content was detected oualitativelv bv Periodic acid-Schiff staininz andquantitatively by anthrone-sulfuric acid method. The Fox01 and Akt protein levels were analyzed by Western blot. Results： Casein injection induced obvious liver inflammation in high fat diet-fed mice（P=O.O00）. The fasting blood glucose levels and the area under the insulin tolerance curve were higher in the casein-injected mice （P=0.040,P=0.025）. The liver glycogen content and the gluconeogenesis related gene G-6-pase and Pepck expression were also increased significantly（P=0.001 ,P=0.00!） ,while the phosphorylation of Akt and Fox01 in the liver decreased obviously （P=0.021, P=0.003） after casein injection. High fat diet alone resulted in higher expression of gluconeogenesis genes （G-6-pase, Pepck）, while the blood glucose levels maintained in the normal range. Conclusion：Chronic inflammation can exacerbate glucose metabolism disorder in obese mice fed with high fat diet, resulting in hyperglycemia. It suggests that chronic inflammation may increase the risk of obese patients developing into type 2 dia- betes, which provides clinical implications for the obese patients to prevent type 2 diabetes.