不同浓度葡萄糖和游离脂肪酸对大鼠骨骼肌细胞株L6细胞胰岛素敏感性和细胞内活性氧的影响

目的研究不同浓度的葡萄糖和游离脂肪酸（FFA）对骨骼肌L6细胞胰岛素敏感性及细胞内活性氧（ROS）的影响。方法L6细胞诱导分化成熟后，分为6组，以5mmol／L葡萄糖为低糖对照组，其中加0．3或1mmol／L的混合FFA为低糖低FFA或低糖高FFA组，以25mmol／L葡萄糖为高糖对照组，其中加0．3和1mmol／L的FFA的培养基为高糖低FFA或高糖高FFA组。干预48h，^3H—D葡萄糖摄取实验（加与不加100nmol／I，胰岛素37℃30rain）验证L6细胞胰岛素敏感性，经荧光探针H2DCFDA观察细胞内ROS含量的变化。结果在5mmol／L葡萄糖组，低糖对照组基础摄糖值为22777．6±6608．7，低糖低FFA组为26027．5±4085．7，低糖高FFA组为146805．1±21099．4。胰岛素刺激后，低糖对照组为76586．5±18450．1，低糖低FFA组为43738土9203．6，低糖高FFA组为32050．6±3362．3，较低糖对照组显著降低（P〈0．01）。在25mmol／L葡萄糖组，基础葡萄糖摄取量为11793．8±551．4，高糖低FFA组11887．3±2082．3高糖高FFA组为13886．1±3872．9，差别无统计学意义（P〉0．05），但较低糖对照组显著降低（P〈0．01）．加入胰岛素刺激后，高糖对照组为42798．8±9441．5，高糖低FFA组为23946．9±3839．6，高糖高FFA组为13886．1±3872．9，各组之间差别显著（P〈0．01）。对细胞内R0s的研究发现，低糖低FFA组为2234．2±477．2，低糖高FFA组为1969．0±480．9，高糖对照组为1969．0土229．4，高糖低FFA组为2]84．5±734．2，高糖高FFA组为2571．3±96．7，可以显著增加的L6细胞内ROS，与低糖对照组（615．3±244．3）相比差别显著（P〈0．01）。除对照组之外的各组之间差别无统计学意义（P〉0．05）。结论高糖和高FFA可以诱导L6细胞出现氧化应激，同时高糖和高FFA是导致骨骼肌细胞胰岛素抵抗的重要原因之一。

The effect of different concentrations of glucose and free fatty acid on insulin sensitivity and intracellular ROS in L6 myocytes

Objective To explore the the effect of high levels of glucose and free fatty acid （FFA） on insulin sensitivity and intracellular reactive oxygen species （ROS） in L6 myocytes. Methods L6 myocytes were cultured and differentiated into mature myocytes, then were cultured for 48 hours in DMEM medium containing 5 mmol/L and 25 mmol/L glucose, or 0.3 mmol/L or 1 mmol/L FFA. Insulin sensitivity of L6 myocytes were assessed by 3H-2-D-glucose uptake stimulated by insulin, and the intracellular ROS was determined according to fluorescence intensity of H2DCFDA. Results After treatment with glucose and/or FFA, the basal glucose uptake of L6 in control was 22777.6 ± 6608.7. And the 0.3 mmol/L of FFA did not put any further effect on the basal glucose uptake（26027.5±4085.7）. The 1 mmol/L FFA greatly decreased the basal glucose uptake, and the treatment with 25 mmol/L glucose or 25 mmol/L glucose plus 0.3 mmol/L or 1 mmol/L FFA significantly decreased the basal glucose uptake. The insulin stimulated glucose uptake was drastically elevated in control and 25 mmol/L glucose group, but the absolute glucose uptake was lowered in 25 mmol/L glucose group. The insluin sensitivity of L6 myocytes reached the lowest in 25 mmol/L glucose plus lmmol/L FFA group. On the other hand , all the treatments obviously induced oxidation stress. Conclusions Both high glucose and high FFA induce obvious oxidation stress in L6 myocytes, and are the important causes of insulin resistance of L6 myoeytes.