Abstract:

Introduction: Maintaining skeletal muscle mass necessitates a precise balance between anabolic and catabolic pathways. This study aimed to investigate the synergistic effects of intramuscular mesenchymal stem cell (MSC) injection combined with resistance and endurance training protocols on the anabolic and catabolic systems of skeletal muscle in male mice.

Method: The present fundamental and multi-group study employed an experimental design on 30 male Wistar mice (10 weeks old). Mice were randomly assigned to five groups: control, MSC injection, endurance training, resistance training, and combined groups (injection + endurance training; injection + resistance training). Protocols included ladder climbing (resistance) and swimming (endurance), initiated five days post-MSC injection. On days 14 and 28, P-AKT, p70S6K, and 4EBP1 proteins (anabolic markers of the mTOR pathway) in the gastrocnemius muscle were measured using Western blot. Statistical analysis was performed using one-way ANOVA and Tukey's post-hoc test via SPSS21 software. To enhance result validity and minimize bias, assessments and sample analyses were conducted in a blinded manner.

Findings: MSC injection in combination with endurance and resistance training significantly increased P-AKT levels in male mice (P<0.05), whereas exercise training alone had no significant effect on P-AKT (P>0.05). Conversely, all four interventions (including exercise-only and combined groups) significantly elevated p70S6K and 4EBP1 levels (P<0.05). Notably, the combination of MSC injection with endurance and resistance training demonstrated a significantly greater effect on these markers compared to independent exercise training (P<0.05).