不同梯度缓释乳清蛋白对D-半乳糖诱导衰老小鼠的增肌效果研究OA

Skeletal muscle atrophy caused by aging is an important issue affecting the quality of life in the elderly.This study constructed a sustained-release whey protein formula with a gradient of 95%～80%based on the complementary metabolic kinetics of whey protein(fast absorption)and β-casein(slow absorption),and systematically evaluated its muscle-building effects using an in vitro aging myotube model induced by D-galactose and an in vivo aging mouse model.The in vitro experiments showed that the 85%and 80%formulas could promote the proliferation of C2C12 myoblasts and increase myotube area.Among them,the 80%formula at 0.10 mg/mL reached the level of the positive control(leucine)regarding myotube area,while the 85%formula required 1.00 mg/mL to achieve a similar effect.Furthermore,the 80%formula promoted the expression of key structural proteins such as myosin heavy chain(MYH1)and actin(ACT1)while inhibiting the mRNA expression of muscle atrophy-related enzymes MuRF1 and Fbxo32,with the best effect observed at 0.10 mg/mL.In vivo experiments confirmed that the low-dose sustained-release intervention group(300 mg/kg)significantly improved the lean mass(ratio),tibialis anterior muscle mass(ratio),gastrocnemius muscle mass(ratio),muscle fiber cross-sectional area,and exercise capacity in D-galactose-induced aging mice,showing no statistical difference with the whey protein group(600 mg/kg)and the high-dose sustained-release intervention group(600 mg/kg)(P>0.05).In conclusion,the 80%sustained-release whey protein optimizes the amino acid release kinetics to achieve the muscle-building efficacy of traditional whey protein at 50%of the dosage,providing a novel nutritional intervention strategy for aging-related muscle atrophy.