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目的:观察大鼠不同类型骨骼肌肌纤维在缺氧、收缩以及两者联合刺激下,其葡萄糖跨膜转运速率(GTR)与肌糖原含量的关系。方法:取不同肌纤维占优势的3种大鼠骨骼肌(比目鱼肌、趾长伸肌和肱骨内上髁肌),离体条件下进行不同的刺激处理(基础对照、缺氧、收缩、缺氧+收缩),测定GTR和肌糖原含量并分析它们之间的关系。结果:骨骼肌肌纤维类型不同,其GTR对缺氧、收缩、缺氧+收缩刺激的反应有所不同,其肌糖原的基础量、不同刺激后的残留量及消耗量也不尽相同。3种肌纤维类型骨骼肌的GTR均与肌糖原的残留量呈负相关倾向,而与消耗量呈正相关倾向。氧化型(Ⅱa型和Ⅰ型)肌纤维(趾长伸肌和比目鱼肌)比酵解型(Ⅱb型)肌纤维(肱骨内上髁肌)在肌糖原消耗量较少的情况下可引起GTR较高的增加。这一结果从肌纤维类型的角度揭示了有氧运动(可更多地动员氧化型肌纤维)在预防和改善胰岛素抵抗中能够发挥重要作用的机理。
OBJECTIVE: To observe the relationship between glucose transport rate (GTR) and muscle glycogen content of different types of skeletal muscle fibers in rats under hypoxia, contraction and combined stimulation. Methods: Three kinds of rat skeletal muscles (soleus, extensor digitorum longus and humerus medial condyle) dominated by different myofibers were treated with different stimuli in vitro (basal control, hypoxia, contraction, hypoxia + Contractions), determine the GTR and muscle glycogen content and analyze the relationship between them. Results: The skeletal muscle fibers of different types, their GTR hypoxia, contraction, hypoxia + contraction stimulation of the response is different, the basis of muscle glycogen, residual stimulation and consumption are not the same. The GTRs of three skeletal muscle types were negatively correlated with muscle glycogen residues, but positively correlated with the consumption. Oxidative (type IIa and type I) myofibers (extensor digitorum longus and soleus muscle) were more likely to cause a GTR-like decrease in myogenic activity than type IIb myofibers (medial supracondylar humerus muscle) High increase. This result reveals, from the perspective of muscle fiber type, the mechanism by which aerobic exercise (which can mobilize more oxidative muscle fiber) can play an important role in preventing and improving insulin resistance.