Abstract: Purpose:The effect of soybean peptides for nutritional intervention on prevention and treatment for muscle atrophy was investigated by stimulating weightlessness in tail-suspension rats. Methods:15 male Wistar rats were selected for the prevention experiment and randomly divided into ground control group,tail suspension-model control group and tail suspension-soybean peptide group,and gavaged for 40 d. 20 male Wistar rats were selected for the treatment experiment,5 rats were used for ground control group and 15 rats were put back to ground after tail suspension for 40 d,and then divided into tail suspension-high dose group,tail suspension-middle dose group and tail suspension-low dose group,and continuously gavaged for 60 d. After the prevention and treatment experiments,rat total body weight,wet weight of gastrocnemius and soleus muscle were weighed;the concentrations of related factors of protein synthesis(IGF-1),protein proteolysis(FoxO3),oxidative stress(SOD)in rat serum and the relative protein expression of key specific ligase(Atrogin-1)in protein proteolysis were determined. Results:In the prevention experiment,compared with tail suspension-model control group,soybean peptides significantly increased the concentration of IGF-1 in rat serum(p<0.05),significantly decreased the concentration of FoxO3 in serum(p<0.05)and significantly decreased the relative protein expression of Atrogin-1 in soleus muscle. In the treatment experiment,compared with tail suspension-model control group,soybean peptides with different doses significantly increased the rate of weight gain in rats(p<0.05),significantly increased the concentrations of IGF-1 and SOD in rat serum(p<0.05),significantly decreased the concentration of FoxO3 in serum(p<0.05)and significantly decreased the relative protein expression of Atrogin-1 in both gastrocnemius and soleus muscle(p<0.05),which were no significant difference with ground control group after recovery for 60 d. Conclusions:Soybean peptides for nutritional intervention can effectively prevent muscle atrophy or improve muscle atrophy by enhancing protein anabolism and reducing protein catabolism to a certain extent,while decrease oxidative stress level in the body.