Physical exercise and a leucine-rich diet modulate the muscle protein metabolism in Walker tumor-bearing rats.
Leucine-supplemented diet can recover lean body mass and preserve muscle protein mass. Additionally, physical exercise can be an excellent alternative to improve the rehabilitation of cancer patients. Knowing these facts, we examined the effects of a leucine-rich diet with or without physical aerobic exercise on muscle protein metabolism in Walker tumor-bearing rats. Young rats were divided into 4 groups that did or did not perform light aerobic exercise (swim training) and were on a leucine-rich diet or a control diet for 2 mo. After this time, these animals were implanted or not with tumors (subcutaneously) following groups for either control diet or leucine-rich diet fed rats: control, trained, tumor-bearing, and trained tumor-bearing. Twenty-one days after implantation, the tumor growth induced a decrease in the muscle protein synthesis and increased the catabolic process, which was associated with an increase in the expression of the ubiquitin-proteasome subunits (20S, 19S, and 11S). In contrast, the exercise program minimized the muscle degradation process and increased muscle myosin content. Additionally, leucine supplementation also modulated proteasome subunits, especially the 19S and 11S. In summary, the exercise has beneficial effects by reducing tumor growth, leading to an improvement in protein turnover especially when in conjunction with a leucine-rich diet.
Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil.
Emilianne M
EM
Salomão
Aline T
AT
Toneto
Gisele O
GO
Silva
Maria Cristina C
MC
Gomes-Marcondes
D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002100:Cachexia / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D002279:Carcinoma 256, Walker / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control; D004032:Diet; D007930:Leucine / Q000008:administration & dosage* / Q000378:metabolism; D008297:Male; D009043:Motor Activity; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D009368:Neoplasm Transplantation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming; D047368:Tumor Burden
D009124:Muscle Proteins; D046988:Proteasome Endopeptidase Complex; C119011:26S proteasome non-ATPase regulatory subunit 13; D018995:Myosin Heavy Chains; D007930:Leucine