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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Leucine-rich diet supplementation modulates foetal muscle protein metabolism impaired by Walker-256 tumour

Texto completo
Autor(es):
Cruz, Bread [1] ; Gomes-Marcondes, Maria C. C. [1]
Número total de Autores: 2
Afiliação do(s) autor(es):
[1] State Univ Campinas UNICAMP, Lab Nutr & Canc, Dept Struct & Funct Biol, Inst Biol, BR-13083862 Sao Paulo - Brazil
Número total de Afiliações: 1
Tipo de documento: Artigo Científico
Fonte: Reproductive Biology and Endocrinology; v. 12, JAN 3 2014.
Citações Web of Science: 12
Resumo

Background: Cancer-cachexia induces a variety of metabolic disorders of protein turnover and is more pronounced when associated with pregnancy. Tumour-bearing pregnant rats have impaired protein balance, which decreases protein synthesis and increases muscle breakdown. Because branched-chain amino acids, especially leucine, stimulate protein synthesis, we investigated the effect of a leucine-rich diet on protein metabolism in the foetal gastrocnemius muscles of tumour-bearing pregnant rats. Methods: Foetuses of pregnant rats with or without Walker 256 tumours were divided into six groups. During the 20 days of the experiment, the pregnant groups were fed with either a control diet (C, control rats; W, tumour-bearing rats; Cp, rats pair-fed the same normoprotein-diet as the W group) or with a leucine-rich diet (L, leucine rats; LW, leucine tumour-bearing rats; and Lp, rats pair-fed the same leucine-rich diet as the LW group). After the mothers were sacrificed, the foetal gastrocnemius muscle samples were resected, and the protein synthesis and degradation and tissue chymotrypsin-like, cathepsin and calpain enzyme activities were assayed. The muscle oxidative enzymes (catalase, glutathione-S-transferase and superoxide dismutase), alkaline phosphatase enzyme activities and lipid peroxidation (malondialdehyde) were also measured. Results: Tumour growth led to a reduction in foetal weight associated with decreased serum protein, albumin and glucose levels and low haematocrit in the foetuses of the W group, whereas in the LW foetuses, these changes were less pronounced. Muscle protein synthesis (measured by L-{[}3H]-phenylalanine incorporation) was reduced in the W foetuses but was restored in the LW group. Protein breakdown (as assessed by tyrosine release) was enhanced in the L and W groups, but chymotrypsin-like activity increased only in group W and tended toward an increase in the LW foetuses. The activity of cathepsin H was significantly higher in the W group foetuses, but the proteolytic calcium-dependent pathway showed similar enzyme activity. In parallel, an intense oxidative stress process was observed only in the group W foetuses. Conclusions: These data suggested that the proteasomal and lysosomal proteolytic pathways and oxidative stress are likely to participate in the process of foetal muscle catabolism of Walker's tumour-bearing pregnant rats. The present work shows that foetal muscle can be protected by supplementation with a leucine-rich diet. (AU)

Processo FAPESP: 11/08276-0 - Ação in vivo de L-leucina sobre sinalização celular e vias metabólicas durante o metabolismo protéico muscular em ratos portadores de tumor Walker 256
Beneficiário:Bread Leandro Gomes da Cruz
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 10/00209-9 - Nutrição e câncer estudo das alterações metabólicas e moleculares do metabolismo protéico no câncer-caquexia, moduladas pela suplementação nutricional com leucina, no crescimento, desenvolvimento e gravidez
Beneficiário:Maria Cristina Cintra Gomes Marcondes
Linha de fomento: Auxílio à Pesquisa - Regular