School of Kinesiology, Western University, Medical Sciences Building 227, London, ON, N6A 3K7, Canada.
Department of Physiology and Pharmacology, Schulich School of Medicine, Western University, London, ON, Canada.
Lipids Health Dis. 2021 Jul 6;20(1):64. doi: 10.1186/s12944-021-01494-w.
Intensive-insulin treatment (IIT) strategy for patients with type 1 diabetes mellitus (T1DM) has been associated with sedentary behaviour and the development of insulin resistance. Exercising patients with T1DM often utilize a conventional insulin treatment (CIT) strategy leading to increased insulin sensitivity through improved intramyocellular lipid (IMCL) content. It is unclear how these exercise-related metabolic adaptations in response to exercise training relate to individual fibre-type transitions, and whether these alterations are evident between different insulin strategies (CIT vs. IIT).
This study examined glycogen and fat content in skeletal muscle fibres of diabetic rats following exercise-training.
Male Sprague-Dawley rats were divided into four groups: Control-Sedentary, CIT- and IIT-treated diabetic sedentary, and CIT-exercised trained (aerobic/resistance; DARE). After 12 weeks, muscle-fibre lipids and glycogen were compared through immunohistochemical analysis.
The primary findings were that both IIT and DARE led to significant increases in type I fibres when compared to CIT, while DARE led to significantly increased lipid content in type I fibres compared to IIT.
These findings indicate that alterations in lipid content with insulin treatment and DARE are primarily evident in type I fibres, suggesting that muscle lipotoxicity in type 1 diabetes is muscle fibre-type dependant.
对于 1 型糖尿病（T1DM）患者，强化胰岛素治疗（IIT）策略与久坐行为和胰岛素抵抗的发展有关。患有 T1DM 的患者经常采用常规胰岛素治疗（CIT）策略，通过提高细胞内脂质（IMCL）含量来提高胰岛素敏感性。目前尚不清楚这些与运动相关的代谢适应如何与个体纤维类型的转变相关，以及这些改变是否在不同的胰岛素策略（CIT 与 IIT）之间存在差异。
本研究旨在观察运动训练后糖尿病大鼠骨骼肌纤维中糖原和脂肪的含量。
雄性 Sprague-Dawley 大鼠分为四组：对照组-久坐，CIT 和 IIT 治疗的糖尿病久坐组，以及 CIT 运动训练组（有氧/阻力；DARE）。12 周后，通过免疫组织化学分析比较肌肉纤维中的脂质和糖原。
主要发现是与 CIT 相比，IIT 和 DARE 均导致 I 型纤维显著增加，而与 IIT 相比，DARE 导致 I 型纤维中的脂质含量显著增加。
这些发现表明，胰岛素治疗和 DARE 引起的脂质含量变化主要在 I 型纤维中明显，这表明 1 型糖尿病中的肌肉脂毒性依赖于肌肉纤维类型。
