Background and objective
The purpose of this study was to investigate the effects of regular exercise training on nicotinamide ade-nine dinucleotide/sirtuin 1 (NAD+/SIRT1) signaling protein levels in skeletal muscles of middle-aged and old-aged mice.
Material and methods
Experimental animals were 40 male C57BL/6 mice out of which 20 were 38-week-old (middle-aged) and the other 20 were 58-week-old (aged). They were divided into four groups: middle-aged control (MC), mid-dle-aged exercise (ME), aged control (AC), and aged exercise (AE) groups (n = 10, each group). ME and AE groups performed exercise training five times weekly for 8 weeks using animal treadmill, after which gastrocnemius muscles were excised and analyzed.
Results
After 8 weeks of intervention, protein levels of AMP-activated protein kinase (AMPK), SIRT1, forkhead box protein 1 (FOXO1), and NAD+ levels were significantly lower in AC group than in MC group (p < 0.05). In addition, AMPK, SIRT1, FOXO1, NAD+, and peroxisome proliferator-activated receptor gamma coact-ivator 1-alpha (PGC-1α) levels were significantly higher in ME and AE groups that exercised for 8 weeks than in MC and AC groups that did not exercise (p < 0.05).
Conclusion
These results suggest that aging and exercise training have opposite effects on the NAD+/SIRT1 pathway in gastrocnemius muscles and that exercise training can be effective in up-regulation of the aging-related NAD+/SIRT1 pathway.