[Improvement and mechanism of Polygonati Rhizoma aqueous extract on exercise-induced fatigue mice]

This study investigated the effect and mechanism of Polygonati Rhizoma aqueous extract on exercise-induced fatigued mice. Male ICR mice aged 6-8 weeks were selected, and the exercise-induced fatigued mice model was built by the "overloaded weight-bearing swimming" method. The Polygonati Rhizoma aqueous extract were administered by oral gavage(0.25, 0.5, 1.0 g·kg~(-1), respectively). The general physiological state(food intake, body weight, back temperature, microcirculation, tail suspension time, etc.) of the mice with exercise-induced fatigue was detected. Exercise endurance was evaluated through exhaustive swimming time, grip strength, and rod rotation time. Fatigue-related biochemical indicators such as lactic acid(LD), lactate dehydrogenase(LDH), creatine kinase(CK) were measured. Skeletal muscle content and mass(body composition, skeletal muscle histomorphology, muscle fiber typing) were analyzed. Glycogen content was quantified, and the expression of molecules related to the signaling of skeletal muscle energy metabolism [adenylate-activated protein kinase(AMPK)/silent information regulator 1(SIRT1)/coactivator α(PGC-1α), as well as ATPase activity)] was examined. The results showed that Polygonati Rhizoma aqueous extract could improve the general physiological state of mice with exercise-induced fatigue(increase in food intake and weight growth rate, increase in body surface temperature and microcirculation blood flow, decrease in tail suspension rest time, and increase in tail suspension upturning times). It also improved exercise endurance(increased exhaustive swimming time, grip strength, and rod rotation time). Additionally, it increased the consumption of metabolites(reduction in the content of LD, LDH and CK), raised skeletal muscle content and the proportion of slow muscle, elevated glycogen reserves, and enhanced the expression of AMPK/SIRT1/PGC-1α signaling pathway related molecules and ATPase activity. In conclusion, Polygonati Rhizoma aqueous extract can alleviate exercise-induced fatigue by activating AMPK/SIRT1/PGC-1α pathway in skeletal muscle, regulating the body's energy metabolism and energy substance storage, and improve muscle exercise endurance.