Effects of aging and caloric restriction on fiber type composition, mitochondrial morphology and dynamics in rat oxidative and glycolytic muscles

Conclusions The present study provides evidence that aging-related muscle atrophy is associated with differential changes in mitochondrial morphology and dynamics in oxidative vs glycolytic muscle fibers. Indeed, we show that oxidative fibers display increased mitochondrial fission/fragmentation, and glycolytic fibers display increased mitochondrial size and branching. Our results also indicate that although CR partially attenuates aging-related changes in the content of proteins regulating mitochondrial dynamics in glycolytic fibers, its anti-aging effect on mitochondrial morphology is restricted to oxidative fibers. These results therefore highlight the critical need to analyze both glycolytic and oxidative muscles to reach complete and accurate conclusions on the effects any intervention, condition, genetic manipulation, or treatment on skeletal muscle mitochondria. Ethics Statement All animal procedures were approved by the Comité Institutionnel de Protection des Animaux de l’UQAM (#CIPA875) and the Centre de recherche de l’hôpital du Sacré-Coeur de Montréal (#FRSQ.01) in compliance with the guidelines of the Canadian Council on Animal Care. Author Contributions JF and GG contributed to the conception and design of the study. JF, J-PL-G, OR and GG collected the data. All authors contributed to data analysis and interpretation. JF and GG wrote the first draft of the manuscript. All authors contributed to manuscript r...
Source: Frontiers in Physiology - Category: Physiology Source Type: research