Exercise training impacts exercise tolerance and bioenergetics in gastrocnemius muscle of non-obese type-2 diabetic Goto-Kakizaki rat in vivo - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Biochimie Année : 2018

Exercise training impacts exercise tolerance and bioenergetics in gastrocnemius muscle of non-obese type-2 diabetic Goto-Kakizaki rat in vivo

Résumé

The functional and bioenergetics impact of regular physical activity upon type-2 diabetic skeletal muscle independently of confounding factors of overweight remains undocumented. Here, gastrocnemius muscle energy fluxes, mitochondrial capacity and mechanical performance were assessed noninvasively and longitudinally in non-obese diabetic Goto-Kakizaki rats using magnetic resonance (MR) imaging and dynamic 31-phosphorus MR spectroscopy (31P-MRS) throughout a 6-min fatiguing bout of exercise performed before, in the middle (4-week) and at the end of an 8-week training protocol consisting in 60-min daily run on a treadmill. The training protocol reduced plasmatic insulin level (-61%) whereas blood glucose and non-esterified fatty acids levels remained unaffected, thereby indicating an improvement of insulin sensitivity. It also increased muscle mitochondrial citrate synthase activity (+45%) but this increase did not enhance oxidative ATP synthesis capacity in working muscle in vivo while glycolytic ATP production was increased (+33%). On the other hand, the training protocol impaired maximal force-generating capacity (-9%), total amount of force produced (-12%) and increased ATP cost of contraction (+32%) during the fatiguing exercise. Importantly, these deleterious effects were transiently worsened in the middle of the 8-week period, in association with reduced oxidative capacity and increased basal [Pi]/[PCr] ratio (an in vivo biomarker of muscle damage). These data demonstrate that the beneficial effect of regular training on insulin sensitivity in non-obese diabetic rat occurs separately from any improvement in muscle mitochondrial function and might be linked to an increased capacity for metabolizing glucose through anaerobic process in exercising muscle.
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Dates et versions

hal-02115424 , version 1 (02-05-2019)

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Citer

Michael Macia, Emilie Pecchi, Martine Desrois, Carole Lan, Christophe Vilmen, et al.. Exercise training impacts exercise tolerance and bioenergetics in gastrocnemius muscle of non-obese type-2 diabetic Goto-Kakizaki rat in vivo. Biochimie, 2018, 148, pp.36-45. ⟨10.1016/j.biochi.2018.02.014⟩. ⟨hal-02115424⟩
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