Skeletal muscle is the most abundant tissue in the human body and mechanical injuries are common; these are frequently of mechanical origins, such as contusion. However, the immediate mitochondrial response to injury and energetic substrate utilisation is still unclear. We evaluated the acute response in mitochondrial function after a single muscle contusion, either in fast twitch fibres (glycolytic metabolism), fast and slow twitch (oxidative and glycolytic metabolism), or slow twitch fibres (oxidative metabolism). Rats were assigned to two groups: control and Lesion (muscle contusion). We collected the gastrocnemius and soleus muscles. The fibres were analysed for mitochondrial respiration, lactate dehydrogenase (LDH), citrate synthase (CS) activity, Ca²⁺ uptake, and H₂O₂ production. We found that muscle injury was able to increase ATP synthesis-dependent and OXPHOS oxygen flux in the oxidative fibres when stimulated by complex I + II substrates. On the other hand, the muscle injury increased hydrogen peroxide (H₂O₂) production when compared to control fibres, and reduced citrate synthase activity; however, it did not change Ca²⁺ uptake. Surprisingly, injury in mixed fibres increased the OXPHOS and ATP synthesis oxygen consumption, and H₂O₂ production, but it reduced Ca²⁺ uptake. The injury in glycolytic fibres did not affect oxygen flux coupled to ATP synthesis, citrate synthase, and lactate dehydrogenase activity, but did reduce Ca²⁺ uptake. Finally, we demonstrated distinct mitochondrial responses between the different muscle fibres, indicating that the mitochondrial dynamics is related to flexibilities in metabolism, and that reactive oxygen species directly affect physiology and normal function.

骨骼肌是人体中最丰富的组织，机械损伤很常见。这些通常是机械性起源，例如挫伤。然而，线粒体对损伤和高能底物利用的即时反应仍不清楚。我们评估了单个肌肉挫伤后线粒体功能的急性反应，包括快速抽搐纤维（糖酵解代谢），快速和慢抽搐（氧化和糖酵解代谢）或慢抽搐纤维（氧化代谢）。将大鼠分为两组：对照组和损伤（肌肉挫伤）。我们收集腓肠肌和比目鱼肌。分析纤维的线粒体呼吸，乳酸脱氢酶（LDH），柠檬酸合酶（CS）活性，Ca ²⁺吸收和H ₂ O₂生产。我们发现，当受到复杂的I + II底物刺激时，肌肉损伤能够增加氧化纤维中的ATP合成依赖性和OXPHOS氧通量。另一方面，与对照纤维相比，肌肉损伤增加了过氧化氢（H ₂ O ₂）的产生，并降低了柠檬酸合酶的活性。然而，它并没有改变Ca ^2+的吸收。出人意料的是，混合纤维中的损伤增加了OXPHOS和ATP合成的耗氧量以及H ₂ O _2的产生，但降低了Ca ^2+的吸收。糖酵解纤维的损伤并未影响与ATP合成，柠檬酸合酶和乳酸脱氢酶活性相关的氧气通量，但确实降低了Ca²⁺吸收。最后，我们证明了不同肌肉纤维之间独特的线粒体反应，表明线粒体动力学与代谢的灵活性有关，并且活性氧直接影响生理和正常功能。