Impact des modalités d'exercice d’endurance sur la composition corporelle et le dépôt de graisse hépatique/musculaire chez les souris C57BL/6J atteintes de MASLD

Details

Supervisors

Deldicque, Louise ; Lannoy, Camille

Faculty

Faculté de pharmacie et des sciences biomédicales

Degree label

Master [120] en sciences biomédicales, à finalité spécialisée: nutrition humaine

Abstract

enMetabolic dysfunction–associated steatotic liver disease (MASLD) is closely linked to obesity and insulin resistance, and myosteatosis is now recognized as an important component of this metabolic phenotype, highlighting the relevance of interventions targeting the liver–muscle axis. The aim of this thesis was to evaluate, in a murine model of established MASLD, the effects of aerobic exercise and to compare two training modalities: moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). Male C57BL/6JRj mice were fed a Western diet (40% fat, 40% carbohydrate, 20% protein, 0.5% cholesterol) combined with a fructose-enriched beverage (30%) for 20 weeks. After an induction period, animals were assigned to three groups (CTRL,MICT, HIIT) and completed an 8-week intervention (5 sessions/week) on a treadmill, with intensities individualized using a maximal aerobic speed (VMA) test. Body weight and fasting glycaemia were monitored, and body composition as well as liver and dorsal muscle density were assessed by micro-CT before and after training. At the end of the protocol, hepatic and muscle lipid assays, qPCR analyses (PGC-1α, VEGF, CD36), and liver histology (NAS score) were performed. Overall, body weight and fasting glycaemia increased under the maintained diet, but these rises were attenuated in the MCT group compared with controls, whereas HIIT did not clearly differ from CTRL for these outcomes. Fat mass and lean mass showed no clear between-group changes. At the tissue level, liver density was not improved by exercise, and hepatic lipids, qPCR markers, and NAS did not differ significantly across modalities. In contrast, a muscle-specific signal emerged: dorsal muscle density increased in the HIIT group, consistent with improved muscle “quality,” despite no clear differences in terminal muscle lipid content. In summary, under a sustained, highly deleterious nutritional environment, MCT appears more favorable for the overall metabolic profile, while HIIT primarily benefits the muscle component.