Volume 10, Issue 2 pp. 130-139
Original Article

Ganglioside GM3 content in skeletal muscles is increased in type 2 but decreased in type 1 diabetes rat models: Implications of glycosphingolipid metabolism in pathophysiology of diabetes

骨骼肌中神经节苷脂GM3的含量在2型糖尿病大鼠模型中增加但在1型糖尿病大鼠模型中减少:鞘糖脂代谢在糖尿病病理生理学中的作用

Josko Bozic

Corresponding Author

Josko Bozic

Department of Pathophysiology, University of Split School of Medicine, Split, Croatia

Correspondence

Josko Bozic, Department of Pathophysiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia.

Tel: +385 21 557 871

Fax: +385 21 557 895

Email: [email protected]

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Anita Markotic

Anita Markotic

Department of Medical Chemistry and Biochemistry, University of Split School of Medicine, Split, Croatia

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Vedrana Cikes-Culic

Vedrana Cikes-Culic

Department of Medical Chemistry and Biochemistry, University of Split School of Medicine, Split, Croatia

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Anela Novak

Anela Novak

Department of Internal Medicine, University Hospital Split, Split, Croatia

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Josip A. Borovac

Josip A. Borovac

Department of Pathophysiology, University of Split School of Medicine, Split, Croatia

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Hrvoje Vucemilovic

Hrvoje Vucemilovic

Department of Anesthesiology and Intensive Care Medicine, University Hospital Split, Split, Croatia

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Gorana Trgo

Gorana Trgo

Department of Internal Medicine, University Hospital Split, Split, Croatia

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Tina Ticinovic Kurir

Tina Ticinovic Kurir

Department of Pathophysiology, University of Split School of Medicine, Split, Croatia

Department of Internal Medicine, University Hospital Split, Split, Croatia

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First published: 22 May 2017
Citations: 16

Abstract

en

Background

Ganglioside GM3 is found in the plasma membrane, where its accumulation attenuates insulin receptor signaling. Considering the role of skeletal muscles in insulin-stimulated glucose uptake, the aim of the present study was to determine the expression of GM3 and its precursors in skeletal muscles of rat models of type 1 and type 2 diabetes mellitus (T1DM and T2DM, respectively).

Methods

Diabetes was induced in male Sprague-Dawley rats by streptozotocin injection (55 mg/kg, i.p., for T1DM induction; 35 mg/kg, i.p., for T2DM induction), followed by feeding of rats with either a normal pellet diet (T1DM) or a high-fat diet (T2DM). Rats were killed 2 weeks after diabetes induction and samples of skeletal muscle were collected. Frozen quadriceps muscle sections were stained with a primary antibody against GM3 (Neu5Ac) and visualized using a secondary antibody coupled with Texas Red. The muscle content of ganglioside GM3 and its precursors was analyzed by high-performance thin-layer chromatography (HPTLC) followed by GM3 immunostaining.

Results

Muscle GM3 content was significantly higher in T2DM compared with control rats (P< 0.001). Furthermore, levels of the GM3 precursors ceramide, glucosylceramide, and lactosylceramide were significantly higher in T2DM compared with control rats (P< 0.05), whereas ceramide content was significantly lower in T1DM rats (P< 0.05). The intensity of the GM3 band on HPTLC was significantly higher in T2DM rats (P < 0.001) and significantly lower in T1DM rats (P< 0.05) compared with control.

Conclusions

The expression patterns of GM3 ganglioside and its precursors in diabetic rats suggest that the role of glycosphingolipid metabolism may differ between T2DM and T1DM.

摘要

zh

背景

神经节苷脂GM3在细胞膜上表达,  它在细胞膜上积聚可以减弱胰岛素受体的信号传导。考虑到骨骼肌在胰岛素刺激后的葡萄糖摄取中所起到的作用,  本研究旨在检测GM3及其前体在1型与2型糖尿病(分别缩写为T1DM与T2DM)大鼠模型骨骼肌中的表达。

方法

雄性Sprague-Dawley大鼠注射链脲霉素后诱导糖尿病(腹腔内注射55 mg/kg诱导T1DM;腹腔内注射35 mg/kg诱导T2DM),  然后分别用正常饲料(T1DM)或者高脂饲料(T2DM)进行饲养。诱导出糖尿病2周之后,  将大鼠处死并且收集骨骼肌样本进行实验。使用一级抗GM3抗体(Neu5Ac)对冰冻四头肌切片进行染色,  使用与德克萨斯红偶联的二级抗体显影。使用高效薄层色谱法以及GM3免疫染色法分析肌肉中神经节苷脂GM3及其前体含量。

结果

T2DM大鼠肌肉中的GM3含量显著高于对照组大鼠(P < 0.001)。此外,  T2DM大鼠GM3前体神经酰胺、葡萄糖基神经酰胺以及乳糖基神经酰胺的水平也显著高于对照组大鼠(P < 0.05),  然而T1DM大鼠的神经酰胺含量却显著降低(P < 0.05)。与对照组大鼠相比,  使用高效薄层色谱法分析后发现T2DM大鼠的GM3条带强度显著增强(P < 0.001),  而T1DM大鼠中却显明显减弱(P < 0.05)。

结论

不同类型糖尿病大鼠的GM3神经节苷脂及其前体表达模式各不相同,  提示鞘糖脂代谢在T2DM与T1DM中的作用可能存在差异。

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