Does sex matter in the cheetah? Insights into the skeletal muscle of the fastest land animal - PubMed (original) (raw)

Does sex matter in the cheetah? Insights into the skeletal muscle of the fastest land animal

Tertius A Kohn et al. J Exp Biol. 2024.

Abstract

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.

Keywords: Acinonyx jubatus; Enzymes; Fibre type; Metabolism.

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Conflict of interest statement

Competing interests The authors declare no competing or financial interests.

Figures

Fig. 1.

Photographs of cheetahs at the AfriCat Foundation. (A) Two male cheetahs. (B) Darting and immobilisation of a cheetah and transportation to the field laboratory. Photo credit: A.S.W.T.

Fig. 2.

Immunohistology of cheetah and human vastus lateralis skeletal muscle biopsies. (A,B) Fibres which stained positively for myosin heavy chain (MHC) isoform I are shown in blue. (C,D) Fibres which stained positively for MHC IIA are shown in green. (E,F) Fibres which stained positively for MHC IIX are shown in red. (G,H) Merged images. Scale bars: 100 µm.

Fig. 3.

Representative SDS-PAGE image of separated myosin heavy chain (MHC) isoforms from human and cheetah skeletal muscle. Lion and rat skeletal muscle was included to provide reference markers to indicate the migration patterns of the various isoforms.

Fig. 4.

Muscle fibre type and cross-sectional area. (A) MHC isoform content, (B) fibre type calculated from immunohistochemistry and (C) fibre cross-sectional area (CSA) of the vastus lateralis muscle from cheetahs and humans as a species and divided into sex. For sample sizes, see Results. Data are presented as means±s.d. *Significantly different from cheetahs within the same fibre type (P<0.05); ‡significantly different from cheetahs of the same sex within the same fibre type (P<0.05); §significantly different from males within the same species (P<0.05).

Fig. 5.

Maximal enzyme activities of cheetah and human vastus lateralis muscle as a species and divided into sex. (A) CS, citrate synthase; (B) 3HAD, 3-hydroxyacyl acetyl co-enzyme A dehydrogenase; (C) CK, creatine kinase; (D) GP, glycogen phosphorylase; (E) PFK, phosphofructokinase; (F) LDH, lactate dehydrogenase; (G) SOD, superoxide dismutase; (H) CAT, catalase; (I) ORAC, oxygen radical absorbance capacity. Refer to Materials and Methods for clarification on the units. Data are presented as means±s.d. (_n_=34 cheetahs and _n_=13 humans). *Significantly different from cheetahs (P<0.05); ‡significantly different from cheetahs within the same sex (P<0.05); §significantly different from males within the same species (P<0.05).

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Does sex matter in the cheetah? Insights into the skeletal muscle of the fastest land animal - PubMed (original) (raw)