A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats

Autor(es)

M.C.C. Gomes-Marcondes ^[1] ; G. Ventrucci ^[2] ; M.T. Toledo ^[3] ; L. Cury ^[4] ; J.C. Cooper ^[5]

Afiliação do(s) autor(es)

^[1] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Fisiologia e Biofísica - Brasil

^[2] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Fisiologia e Biofísica - Brasil

^[3] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Fisiologia e Biofísica - Brasil

^[4] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Fisiologia e Biofísica - Brasil

^[5] The Babraham Institute. Laboratory of Lymphocyte Signalling and Development - Ucrânia

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 36, n. 11, p. 1589-1594, 2003-11-00.

Resumo

Cancer cachexia induces host protein wastage but the mechanisms are poorly understood. Branched-chain amino acids play a regulatory role in the modulation of both protein synthesis and degradation in host tissues. Leucine, an important amino acid in skeletal muscle, is higher oxidized in tumor-bearing animals. A leucine-supplemented diet was used to analyze the effects of Walker 256 tumor growth on body composition in young weanling Wistar rats divided into two main dietary groups: normal diet (N, 18% protein) and leucine-rich diet (L, 15% protein plus 3% leucine), which were further subdivided into control (N or L) or tumor-bearing (W or LW) subgroups. After 12 days, the animals were sacrificed and their carcass analyzed. The tumor-bearing groups showed a decrease in body weight and fat content. Lean carcass mass was lower in the W and LW groups (W = 19.9 ± 0.6, LW = 23.1 ± 1.0 g vs N = 29.4 ± 1.3, L = 28.1 ± 1.9 g, P < 0.05). Tumor weight was similar in both tumor-bearing groups fed either diet. Western blot analysis showed that myosin protein content in gastrocnemius muscle was reduced in tumor-bearing animals (W = 0.234 ± 0.033 vs LW = 0.598 ± 0.036, N = 0.623 ± 0.062, L = 0.697 ± 0.065 arbitrary intensity, P < 0.05). Despite accelerated tumor growth, LW animals exhibited a smaller reduction in lean carcass mass and muscle myosin maintenance, suggesting that excess leucine in the diet could counteract, at least in part, the high host protein wasting in weanling tumor-bearing rats. (AU)

• Processo FAPESP: 01/02135-3 - Efeito da associação entre nutrição, câncer e gravidez: estudo dos processos metabólicos e moleculares da caquexia in vivo in vitro
• Beneficiário: Maria Cristina Cintra Gomes Marcondes
• Modalidade de apoio: Auxílio à Pesquisa - Regular