Ding, W.; Cao, J.; Guo, C.; Liu, W.; Li, X.; Xiao, G.

Background: Exercise-induced fatigue is a complex physiological phenomenon involving oxidative stress, inflammation, and metabolic disturbances. Ergothioneine (EGT), a naturally occurring amino acid with potent antioxidant properties, has garnered interest for its potential health benefits. This study aimed to evaluate the anti-fatigue effects of Gene III EGT in a mouse model of exhaustive exercise and to elucidate its underlying mechanisms. Methods: Male C57BL/6 mice were randomly divided into five groups: a control group (CTL), low-dose EGT (EGT-L, 10 mg/kg), medium-dose EGT (EGT-M, 30 mg/kg), high-dose EGT (EGT-H, 50 mg/kg), and a positive control group (Coenzyme Q10, 50 mg/kg). Mice were subjected to a 4-week treadmill training protocol, followed by an exhaustive running test. We measured exercise performance and collected blood and skeletal muscle samples at multiple time points to assess biochemical markers, inflammatory cytokines, antioxidant status, and key signaling proteins. Results: Gene III EGT supplementation, particularly at medium and high doses, significantly extended the time to exhaustion and running distance. Compared to the control group, EGT treatment significantly reduced post-exercise levels of lactic acid (LA), lactate dehydrogenase (LDH), and blood urea nitrogen (BUN). Furthermore, Gene III EGT suppressed the exercise-induced increase in pro-inflammatory cytokines, including IL-1{beta}, IL-6, and TNF-. The anti-fatigue effect of EGT was also associated with a reduction in malondialdehyde (MDA) and an increase in the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Mechanistically, EGT promoted the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1) in skeletal muscle, while also increasing the Bcl-2/Bax ratio, suggesting enhanced mitochondrial biogenesis and reduced apoptosis. Conclusions: Our findings demonstrate that Gene III EGT effectively enhances exercise performance and alleviates fatigue. The underlying mechanisms involve the mitigation of oxidative stress and inflammation, as well as the activation of the AMPK/PGC-1 signaling pathway to promote mitochondrial function and cellular protection. These results highlight the potential of Gene III EGT as a nutritional supplement for combating exercise-induced fatigue. Keywords: Ergothioneine; Exercise-induced fatigue; Oxidative stress; AMPK; PGC-1; Mitochondrial biogenesis