地塞米松影响肝细胞糖代谢机制及吡格列酮干预作用的研究

Effect and its Mechanism of dexamethasone and pioglitazone intervention on glucose metabolism in HepG2 cells

目的研究地塞米松(DEX)在细胞水平对肝脏糖代谢和胰岛素的生物效应的影响,并观察吡格列酮(PGZ)在该过程中的干预作用。方法体外培养HepG2细胞,加入DEX作用不同的时间,GOD-POD法测上清葡萄糖浓度来确定影响细胞葡萄糖消耗量(GC)最明显的DEX作用时间,并观察PGZ在该条件下对细胞GC、糖原合成、糖异生及糖酵解过程的干预作用。结果 1μmol/L DEX作用36h时细胞GC下降最明显,作用48h时出现IR。PGZ组细胞糖原合成、糖异生指标较DEX组差异均有统计学意义(P均<0.05),糖酵解指标差异无统计学意义(P>0.05),但在胰岛素存在时,PGZ和胰岛素在促进葡萄糖合成和酵解、抑制糖异生等糖代谢的各个环节均发挥协同作用(P<0.05)。结论 DEX作用于肝细胞使其葡萄糖摄取能力及IS下降。PGZ通过糖代谢的多种途径发挥干预作用,其中主要通过糖原合成和糖异生,为临床上类固醇性糖尿病的治疗提供了分子基础。

Objective To study the effect of dexamethasone on glucose metabolism and insulin sensitivity in HepG2 cells, and observe the intervention of pioglitazone on it. Methods Dexamethasone was added into the cultured HepG2 cells for different culture duration, and the GOD-POD method was used to ascertain the best action time of dexamethasone for the most obvious effect on glucose metabolism of HepG2 cells. Based on this, the intervention effect of pioglitazone through measuring the indicators of glucose consumption （GC）, glycogen synthesis, gluconeogenesis, and glycolysis was observed. Results With the intervention of 1 μmol/L dexamethasone for 36 hours, the decrease of GC of cells was the most significant, and IR occurred at 48 hours. The glycogen synthesis and gluconeogenesis of the PGZ group were significantly different from those of the dexamethasone group （all P〈0. 05）, while there was no statistical significant difference in indicators of glycolysis between the two groups （P〉0. 05）. Insulin and pioglitazone had the co-effect on promoting glucose synthesis, glycolysis, and inhibiting gluconeogenesis when insulin was existed at the same time （P〈0. 05）. Conleusion Dexamethasone affects HepG2 cells, causing a decline of glucose intaking and IS. The action of PGZ on glucose metabolism is via glycogen synthesis and gluconeogenesis in a principal way. This conclusion provides more evidence for the clinical treatment of steroid diabetes.