The Impact of Frailty Syndrome on Skeletal Muscle Histology and the Preventive Effects of Exercise

Background Aging-induced frailty syndrome leads to significant functional decline in skeletal muscle. The specific histological changes in skeletal muscle due to frailty syndrome are not well-defined. While the positive effects of exercise on skeletal muscle histology are documented, its preventive impact on frailty syndrome requires further exploration. This study investigates the impact of frailty syndrome on skeletal muscle histology and evaluates the preventive effects of exercise. Method Mice were divided into five groups: young, adult, old, frailty syndrome, and exercise. The exercise group underwent endurance exercise for 60 minutes, three times a week, for 16 weeks. Body weight and lean mass ratio were measured. Muscle fiber cross-sectional area (CSA), myofiber number, extracellular matrix (ECM) content,and myosin heavy chain (MHC) isoforms of the plantaris, tibialis anterior, and quadriceps muscles were evaluated. Results Compared to the old group, the frailty syndrome group showed increased body weight and ECM content, with reductions in CSA and fiber number (P < 0.05). The proportion of MHC isoforms in skeletal muscles remained unchanged. Exercise significantly reduced body weight and ECM content, while increasing CSA, fiber number, and lean mass ratio (P < 0.05). Conclusion Frailty syndrome induces histological changes in skeletal muscle, contributing to functional decline. Exercise can mitigate these changes, highlighting its potential in preventing skeletal muscle muscle dysfunction associated with frailty syndrome. These findings provide valuable insights for the prevention, diagnosis, and treatment of frailty syndrome.