Abstract Maturation and ageing are associated with muscle growth and wasting, respectively. Comparing partially matured animals with those in early ageing may mask age effects on muscle morphology. To investigate this, we compared capillarisation, fibre type composition, fibre size (FCSA) and oxidative capacity of individual fibres of the soleus (SOL), extensor digitorum longus (EDL) and diaphragm (DIA) muscles in 20- (adult) and 79-week-old (early ageing) CD-1 female mice. The FCSA was larger and the capillary density (CD) lower at 79 than 20 weeks in the DIA, while in the EDL the opposite was found (p < 0.02). There were no significant age-related differences in FCSA and CD in the SOL. The heterogeneity in capillary spacing was highest in muscles from 20-week-old mice, irrespective of muscle (p ≤ 0.011). Succinate dehydrogenase activity (SDH-OD), an indicator of oxidative capacity, progressively declined with age in the DIA only (p < 0.010). At all ages, the capillary supply to a fibre was positively related to FCSA in each muscle. We conclude that in mice late maturation (20 weeks) and early ageing (79 weeks) differ, and patterns of changes in FCSA and CD differ between the DIA, EDL and SOL. The relationship between the capillary supply to a fibre with fibre size is similar throughout maturation and ageing, and is independent of muscle of origin and oxidative capacity. Keywords: Ageing, Maturation, Capillarisation, Oxidative capacity, Skeletal muscle
Physiology 2019 (Aberdeen, UK) (2019) Proc Physiol Soc 43, C064
Oral Communications: Morphological alterations of mouse skeletal muscle during late maturation and early ageing are muscle specific
G. M. Messa1, M. Piasecki2, J. Hurst3, J. McPhee4, J. Tallis5, H. Degens1,5,6
1. Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom. 2. MRC-ARUK Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, United Kingdom. 3. Center for Sport, Exercise and Life Sciences, Coventry University, Coventry, United Kingdom. 4. Department of Sport and Exercise Sciences, Research Centre for Musculoskeletal Science & Sports Medicine, Manchester Metropolitan University, Manchester, United Kingdom. 5. Institute of Sport Science and Innovations, Lithuanian Sports University, Lithuania, Lithuania. 6. University of Medicine and Pharmacy of Targu Mures, Targu Mures, Romania.
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