How Soon Do Metabolic Alterations and Oxidative Distress Precede the Reduction of Muscle Mass and Strength in Wistar Rats?

Abstract Our objective was to investigate how metabolic changes, the antioxidant system and the accumulation of oxidative damage occur in muscles with different fibre populations during the ageing process of Wistar rats, as well as to try to map the key age at which these changes occur. For this, 30 male Wistar rats were euthanized aged 11, 15 and 19 months. Then, changes in energy metabolism, antioxidant system and oxidative damage in the soleus and extensor digitorum longus muscles were determined. In this sense, it was possible to observe that changes in body characteristics occur after 15 months of age. Regarding muscle biochemical alterations, we can observe that the soleus muscle presents alterations in protein and anaerobic metabolism only at 19 months, while the extensor digitorum longus presents these alterations at 15 months. Even with the different induction of the antioxidant system between the muscles, the damage accumulation is similar between the two muscles. Therefore, it is possible to conclude that at 15 months of age, the metabolic changes that lead to the reduction of muscle mass and strength found in ageing begin, being, therefore, a key age for the application of interventions that seek to curb the reduction of mass and muscle strength, promoting a better quality of life for individuals.