Pendant la phase précoce de récupération, le muscle tibialis anterior s’atrophie et présente des altérations prononcées et persistantes du tissu conjonctif, de la protéolyse et de l’apoptose

National audienc

Effects of high-intensity interval training and moderate-intensity continuous training on glycaemic control and skeletal muscle mitochondrial function in db/db mice

Physical activity is known as an effective strategy for prevention and treatment of Type 2 Diabetes. The aim of this work was to compare the effects of a traditional Moderate Intensity Continuous Training (MICT) with a High Intensity Interval Training (HIIT) on glucose metabolism and mitochondrial function in diabetic mice. Diabetic db/db male mice (N = 25) aged 6 weeks were subdivided into MICT, HIIT or control (CON) group. Animals in the training groups ran on a treadmill 5 days/week during 10 weeks. MICT group ran for 80 min (0 degrees slope) at 50-60% of maximal speed (Vmax) reached during an incremental test. HIIT group ran thirteen times 4 minutes (20 degrees slope) at 85-90% of Vmax separated by 2-min-rest periods. HIIT lowered fasting glycaemia and HbA1c compared with CON group (p < 0.05). In all mitochondrial function markers assessed, no differences were noted between the three groups except for total amount of electron transport chain proteins, slightly increased in the HIIT group vs CON. Western blot analysis revealed a significant increase of muscle Glut4 content (about 2 fold) and higher insulin-stimulated Akt phosphorylation ratios in HIIT group. HIIT seems to improve glucose metabolism more efficiently than MICT in diabetic mice by mechanisms independent of mitochondrial adaptation

High intensity interval training improves glucose metabolism in diabetic mice despite limited mitochondrial adaptations

National audienceRecent studies have proved in patients with type 2 diabetes the positive effects of High Intensity Interval Training (HIIT) programs on hyperglycemia and muscle mitochondrial capacity. The aim of this work was to compare the effects of HIIT with a traditional Moderate Intensity Continuous Training (MICT) on glucose metabolism and mitochondrial function in diabetic mice. 25 db/db mice aged 6 weeks were subdivided into MICT group, HIIT group, or control group (CON). Animals in the training groups ran on a treadmill 5 days/week during 10 weeks. In vivo, ex vivo and post-mortem biochemical measurements were performed at the end at the end of the protocol. HIIT lowered fasting glycemia (-40% vs CON) and HbA1c (-20% vs CON), and improved response to starch and insulin tolerance tests vs CON group. No changes were noted in MICT group regarding the glucose homeostasis. 24h respiratory exchange ratio was increased in HIIT (+6% vs CON) and MICT group (+4% vs CON) after the training program but without any changes in 24h total energy expenditure. ETC protein content was increased in HIIT vs CON, whereas other mitochondrial density markers were unchanged. Western blot analysis revealed a significant increase of muscle Glut4 content and higher Akt phosphorylation ratios only in HIIT group. This study showed that HIIT may improve glucose metabolism more efficiently than traditional MICT in diabetic mice by mechanisms independent of mitochondrial adaptations. As already reported in the literature, intact leptin signaling might be necessary for exercise-induced adaptation of mitochondrial function through AMPK and Sirt1 in the muscl

High intensity interval training improves glucose metabolism in diabetic mice despite limited mitochondrial adaptations

National audienceRecent studies have proved in patients with type 2 diabetes the positive effects of High Intensity Interval Training (HIIT) programs on hyperglycemia and muscle mitochondrial capacity. The aim of this work was to compare the effects of HIIT with a traditional Moderate Intensity Continuous Training (MICT) on glucose metabolism and mitochondrial function in diabetic mice. 25 db/db mice aged 6 weeks were subdivided into MICT group, HIIT group, or control group (CON). Animals in the training groups ran on a treadmill 5 days/week during 10 weeks. In vivo, ex vivo and post-mortem biochemical measurements were performed at the end at the end of the protocol. HIIT lowered fasting glycemia (-40% vs CON) and HbA1c (-20% vs CON), and improved response to starch and insulin tolerance tests vs CON group. No changes were noted in MICT group regarding the glucose homeostasis. 24h respiratory exchange ratio was increased in HIIT (+6% vs CON) and MICT group (+4% vs CON) after the training program but without any changes in 24h total energy expenditure. ETC protein content was increased in HIIT vs CON, whereas other mitochondrial density markers were unchanged. Western blot analysis revealed a significant increase of muscle Glut4 content and higher Akt phosphorylation ratios only in HIIT group. This study showed that HIIT may improve glucose metabolism more efficiently than traditional MICT in diabetic mice by mechanisms independent of mitochondrial adaptations. As already reported in the literature, intact leptin signaling might be necessary for exercise-induced adaptation of mitochondrial function through AMPK and Sirt1 in the muscl

Effects of high-intensity interval training and moderate-intensity continuous training on glycaemic control and skeletal muscle mitochondrial function in db/db mice

The authors wish to thank Mr Mehdi Djelloul-Mazouz and Mr Philippe Denis from INRA Unité de Nutrition Humaine (UNH, UMR 1019), CRNH Auvergne (France) for the care and the attention to the animals. We also thank Mrs Monique Etienne from AME2P Lab (Clermont-Ferrand, France) and Mrs Anne-Sophie Galvardon for their excellent assistance during the experimentsInternational audiencePhysical activity is known as an effective strategy for prevention and treatment of Type 2 Diabetes. The aim of this work was to compare the effects of a traditional Moderate Intensity Continuous Training (MICT) with a High Intensity Interval Training (HIIT) on glucose metabolism and mitochondrial function in diabetic mice. Diabetic db/db male mice (N = 25) aged 6 weeks were subdivided into MICT, HIIT or control (CON) group. Animals in the training groups ran on a treadmill 5 days/week during 10 weeks. MICT group ran for 80 min (0 degrees slope) at 50-60% of maximal speed (Vmax) reached during an incremental test. HIIT group ran thirteen times 4 minutes (20 degrees slope) at 85-90% of Vmax separated by 2-min-rest periods. HIIT lowered fasting glycaemia and HbA1c compared with CON group (p < 0.05). In all mitochondrial function markers assessed, no differences were noted between the three groups except for total amount of electron transport chain proteins, slightly increased in the HIIT group vs CON. Western blot analysis revealed a significant increase of muscle Glut4 content (about 2 fold) and higher insulin-stimulated Akt phosphorylation ratios in HIIT group. HIIT seems to improve glucose metabolism more efficiently than MICT in diabetic mice by mechanisms independent of mitochondrial adaptation

High intensity interval training promotes total and visceral fat mass loss in obese Zucker rats without modulating gut microbiota

AimsIncreased visceral adipose tissue and dysbiosis in the overweight and obese promote chronic inflammation. The aim of this study was to compare the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on the gut-adipose tissue cross-talk in obese Zucker rats.MethodsObese male Zucker rats (n = 36) were divided in three groups: MICT (12m.min(-1) for 51 min), HIIT (6 sets at 18 m.min(-1) for 4min followed by 3min at 10m.min(-1)) and controls (CONT; no exercise). The animals ran on a treadmill 5 days/week for 10 weeks. Body composition, glycaemic control, lipid profile, inflammation, lipolysis signalling in subcutaneous and visceral adipose tissue, intestinal permeability (tight junctions and plasma lipopolysaccharide binding protein; LBP), and gut microbiota composition were assessed in the three groups.ResultsAfter 10 weeks of exercise, total and epididymal fat mass decreased only in the HIIT group. The alpha/beta adrenergic receptor RNA ratio in subcutaneous adipose tissue increased only in the HIIT group. The expression level of phosphorylated hormone-sensitive lipase was not modified by training. Both HIIT and MICT decreased inflammation (plasma myeloperoxidase and keratinocyte-derived chemokine secretion in adipose tissue) and improved glucose metabolism. Zonula occludens-1 and occludin were upregulated in the HIIT group. Plasma LBP was similarly reduced in both training groups. HIIT and MICT did not affect gut microbiota composition.ConclusionIn obese Zucker rats, HIIT and MICT improved inflammation and glucose metabolism. In contrast, only HIIT decreased total and visceral fat mass. These adaptations were not associated with modifications in gut microbiota composition

Preventive effect of spontaneous physical activity on gut-adipose tissuecross-talk in CEABAC10 mice exposed by associated adherent-invasive Escherichia coli bacteria after training

communications session 3 METABOLIC DISORDERS AND MUSCLE INTEGRITYPreventive effect of spontaneous physical activity on gut-adipose tissuecross-talk in CEABAC10 mice exposed by associated adherent-invasive Escherichia coli bacteria after training. Fifth International Congress of Translational Research in Human Nutrition (ICTRHN

Preventive Effect of Spontaneous Physical Activity on the Gut-Adipose Tissue in a Mouse Model That Mimics Crohn’s Disease Susceptibility

This article belongs to the Special Issue The Molecular and Cellular Basis for Inflammatory Bowel Diseases (IBD)International audienceCrohn’s disease is characterized by abnormal ileal colonization by adherent-invasive E. coli (AIEC) and expansion of mesenteric adipose tissue. This study assessed the preventive effect of spontaneous physical activity (PA) on the gut-adipose tissue in a mouse model that mimics Crohn’s disease susceptibility. Thirty-five CEABAC10 male mice performed spontaneous PA (wheel group; n = 24) or not (controls; n = 11) for 12 weeks. At week 12, mice were orally challenged with the AIEC LF82 strain for 6 days. Body composition, glycaemic control, intestinal permeability, gut microbiota composition, and fecal short-chain fatty acids were assessed in both groups. Animals were fed a high fat/high sugar diet throughout the study. After exposure to AIEC, mesenteric adipose tissue weight was lower in the wheel group. Tight junction proteins expression increased with spontaneous PA, whereas systemic lipopolysaccharides were negatively correlated with the covered distance. Bifidobacterium and Lactobacillus decreased in controls, whereas Oscillospira and Ruminococcus increased in the wheel group. Fecal propionate and butyrate were also higher in the wheel group. In conclusion, spontaneous physical activity promotes healthy gut microbiota composition changes and increases short-chain fatty acids in CEABAC10 mice fed a Western diet and exposed to AIEC to mimic Crohn’s disease

The worsening of tibialis anterior muscle atrophy during recovery post-immobilization correlates with enhanced connective tissue area, proteolysis, and apoptosis

International audienceSlimani L, Micol D, Amat J, Delcros G, Meunier B, Taillandier D, Polge C, Bechet D, Dardevet D, Picard B, Attaix D, Listrat A, Combaret L. The worsening of tibialis anterior muscle atrophy during recovery post-immobilization correlates with enhanced connective tissue area, proteolysis, and apoptosis. Am J Physiol Endocrinol Metab 303: E1335-E1347, 2012. First published October 2, 2012; doi:10.1152/ajpendo.00379.2012.-Sustained muscle wasting due to immobilization leads to weakening and severe metabolic consequences. The mechanisms responsible for muscle recovery after immobilization are poorly defined. Muscle atrophy induced by immobilization worsened in the lengthened tibialis anterior (TA) muscle but not in the shortened gastrocnemius muscle. Here, we investigated some mechanisms responsible for this differential response. Adult rats were subjected to unilateral hindlimb casting for 8 days (I8). Casts were removed at I8, and animals were allowed to recover for 10 days (R1 to R10). The worsening of TA atrophy following immobilization occurred immediately after cast removal at R1 and was sustained until R10. This atrophy correlated with a decrease in type IIb myosin heavy chain (MyHC) isoform and an increase in type IIx, IIa, and I isoforms, with muscle connective tissue thickening, and with increased collagen (Col) I mRNA levels. Increased Col XII, Col IV, and Col XVIII mRNA levels during TA immobilization normalized at R6. Sustained enhanced peptidase activities of the proteasome and apoptosome activity contributed to the catabolic response during the studied recovery period. Finally, increased nuclear apoptosis prevailed only in the connective tissue compartment of the TA. Altogether, the worsening of the TA atrophy pending immediate reloading reflects a major remodeling of its fiber type properties and alterations in the structure/composition of the extracellular compartment that may influence its elasticity/stiffness. The data suggest that sustained enhanced ubiquitin-proteasome-dependent proteolysis and apoptosis are important for these adaptations and provide some rationale for explaining the atrophy of reloaded muscles pending immobilization in a lengthened position