Effects of curcumin and aerobic exercise on apoptosis and the IGF-1/PI3K/AKT/mTOR pathway in the muscle of aged rats with sarcopenia

Background This study aimed to investigate the effects of curcumin supplementation and aerobic exercise on delaying age-related skeletal muscle atrophy and to further explore their potential synergistic effects. The findings are expected to provide a theoretical basis for alleviating skeletal muscle dysfunction and reducing muscle mass loss in the elderly, thereby offering a feasible strategy for the intervention of age-related sarcopenia. Methods In this study, 18-month-old rats were randomly divided into six groups. The rats underwent 8 weeks of aerobic exercise and curcumin intervention. Hematoxylin and eosin staining and a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay were used to compare the morphological structure and apoptosis of skeletal muscle cells in each group, as well as the skeletal muscle tension. The expression levels of proteins related to the IGF-1/PI3K/AKT/mTOR, AMPK/PGC-1, and CaMK signaling pathways, as well as LC3-1 and ULK1, were determined to investigate the anti-aging effects of curcumin and aerobic exercise on skeletal muscle. Results Constant-load aerobic exercise alleviated skeletal muscle loss, reduced the apoptosis index, and upregulated IGF-1/PI3K/AKT/mTOR pathway proteins in aged rats. It also activated AMPK/PGC-1 and CaMK signaling to regulate mitochondrial function, lowered LC3-I and ULK1 expression, and improved muscle tension. Curcumin yielded comparable benefits, albeit with weaker effects than constant-load aerobic exercise. Conclusion Curcumin combined with constant-load aerobic exercise increased the cross-sectional area of skeletal muscle, improved muscle tension, attenuated myocyte apoptosis, and upregulated the expression of growth-associated proteins in aged rats. Meanwhile, the expression levels of LC3-1and ULK1 were markedly downregulated. Among all intervention regimens, constant-load aerobic exercise yielded the most pronounced beneficial outcomes; however, no synergistic effects were detected in the combined treatment with curcumin. Collectively, this study demonstrates that supplementation with the exogenous antioxidant curcumin combined with constant-load aerobic exercise can effectively restrain skeletal muscle apoptosis and mitigate age-related sarcopenia.