Boosting muscle health in aging rats: The synergistic effect of vitamin C, silymarin, and endurance swimming on a high-fat diet

BACKGROUND: This paper inspects the influence of 8-week endurance swimming supplemented with vitamin C and Silymarin on histopathological changes and some gene markers of skeletal muscle hypertrophy in aged rats receiving a high-fat diet (HFD). METHODS: Twenty-five aged male Wistar rats underwent random allocation to five groups, including a normal diet (Control), HFD, HFD + combined vitamin C and Silymarin supplementation (HFD+CS), HFD + endurance swimming (HFD+ES), and HFD + CS + ES. After six weeks of HFD, CS was gavaged to rats as the selected intervention together with HFD in the supplementation groups over eight weeks. Besides, the exercise groups received swimming exercise training five days/week over eight weeks. RESULTS: HFD increased the lipid profile and fat penetration into the liver tissue of elderly rats. Meanwhile, endurance swimming exercises and a combined supplement significantly improved the liver tissue and regulated the lipid profile. The examination of muscle tissue and gene changes revealed that HFD could increase muscle atrophy and reduce the 4E-BP1, S6K1, and mTOR gene levels, while the combination of exercise and supplementation could increase the 4E-BP1, S6K1, and IGF-1 gene levels and improve muscle fiber diameter in aged rats. CONCLUSION: Endurance swimming training with vitamin C and silymarin supplementation in aging NAFLD model rats can improve lipid profile factors and skeletal muscle tissue fiber diameter.