Kohn Tertius A, Knobel Samantha, Donaldson Byron, van Boom Kathryn M, Blackhurst Dee M, Peart James M, Jensen Jørgen, Tordiffe Adrian S W
Department of Medical Biosciences, Faculty of Natural Sciences, University of the Western Cape, Cape Town, 7530, South Africa.
Department of Human Biology, University of Cape Town, Cape Town, 7925, South Africa.
J Exp Biol. 2024 Aug 1;227(15). doi: 10.1242/jeb.247284.
The cheetah is considered the fastest land animal, but studies on their skeletal muscle properties are scarce. Vastus lateralis biopsies, obtained from male and female cheetahs as well as humans, were analysed and compared for fibre type and size, and metabolism. Overall, cheetah muscle had predominantly type IIX fibres, which was confirmed by the myosin heavy chain isoform content (mean±s.d. type I: 17±8%, type IIA: 21±6%, type IIX: 62±12%), whereas human muscle contained predominantly type I and IIA fibres (type I: 49±14%, type IIA: 43±8%, type IIX: 7±7%). Cheetahs had smaller fibres than humans, with larger fibres in the males compared with their female counterparts. Citrate synthase (16±6 versus 28±7 µmol min-1 g-1 protein, P<0.05) and 3-hydroxyacyl co-enzyme A dehydrogenase (30±11 versus 47±15 µmol min-1 g-1 protein, P<0.05) activities were lower in cheetahs than in humans, whereas lactate dehydrogenase activity was 6 times higher in cheetahs (2159±827 versus 382±161 µmol min-1 g-1 protein, P<0.001). The activities of creatine kinase (4765±1828 versus 6485±1298, P<0.05 µmol min-1 g-1 protein) and phosphorylase (111±29 versus 216±92 µmol min-1 g-1 protein) were higher in humans, irrespective of the higher type IIX fibres in cheetahs. Superoxide dismutase and catalase, markers of antioxidant capacity, were higher in humans, but overall antioxidant capacity was higher in cheetahs. To conclude, fibre type, fibre size and metabolism differ between cheetahs and humans, with limited differences between the sexes.
猎豹被认为是陆地速度最快的动物，但对其骨骼肌特性的研究却很匮乏。对从雄性和雌性猎豹以及人类身上获取的股外侧肌活检样本进行了分析和比较，以研究纤维类型、大小及新陈代谢情况。总体而言，猎豹肌肉主要由IIX型纤维组成，这一点通过肌球蛋白重链亚型含量得到证实（平均值±标准差：I型：17±8%，IIA型：21±6%，IIX型：62±12%），而人类肌肉主要由I型和IIA型纤维组成（I型：49±14%，IIA型：43±8%，IIX型：7±7%）。猎豹的纤维比人类的小，且雄性猎豹的纤维比雌性猎豹的大。猎豹的柠檬酸合酶（16±6对28±7 μmol·min⁻¹·g⁻¹蛋白质，P<0.05）和3-羟酰基辅酶A脱氢酶（30±11对47±15 μmol·min⁻¹·g⁻¹蛋白质，P<0.05）活性低于人类，而猎豹的乳酸脱氢酶活性比人类高6倍（2159±827对382±161 μmol·min⁻¹·g⁻¹蛋白质，P<0.001）。无论猎豹的IIX型纤维比例较高，人类的肌酸激酶（4765±1828对6485±1298，P<0.05 μmol·min⁻¹·g⁻¹蛋白质）和磷酸化酶（111±29对216±92 μmol·min⁻¹·g⁻¹蛋白质）活性都更高。抗氧化能力的标志物超氧化物歧化酶和过氧化氢酶在人类中含量更高，但猎豹的总体抗氧化能力更高。总之，猎豹和人类在纤维类型、纤维大小及新陈代谢方面存在差异，两性之间的差异有限。
