title: Whey protein increases muscle weight gain through inhibition of oxidative effects induced by resistance exercise in rats.
abstract: Whey protein (WP) is known for its nutritional value and antioxidant properties. The aim of this study was to evaluate whether the antioxidant properties of WP could contribute to muscle weight gain in response to resistance exercise (RE). We hypothesized that WP ingestion could increase muscle weight gain in rats subjected to an RE program, through inhibition of oxidative effects induced by high-intensity RE. Thirty-two male Fischer rats were randomly assigned to control sedentary, control exercised, WP sedentary, and WP exercised groups (n=8/group). The RE consisted of inducing the rats to perform sets of jumps for 8 weeks. Body and muscle weight gains, muscle glutathione content, histopathology, muscle antioxidant enzyme activities, and gene expression were evaluated. Body and muscle weight gains of exercised rats fed WP were higher than those of control exercised rats. Concomitantly, RE induced an increase in phagocyte infiltration, protein oxidation, and down-regulation of glutathione peroxidase and gamma-glutamylcysteine synthetase messenger RNA expression in gastrocnemius muscle (P<.05), effects that were inhibited by WP ingestion. Cytosolic superoxide dismutase and catalase messenger RNA expression were reduced only by RE (P<.05), and muscle glutathione content was increased only by WP (P<.05) with no significant interaction observed (P>.05). These findings suggest that differences in body and muscle weight gain in exercised rats fed control or WP diets were mediated, in part, by the antioxidant properties of WP, and indicate that when associated with RE, WP represents a nutritional aid to support muscle growth.
authors.affiliation: Programa de Pós-Graduação em Saúde e Nutrição (PPGSN), School of Nutrition, University of Ouro Preto (UFOP), Minas Gerais, Brazil.
authors.forename: Kely R
authors.initials: KR
authors.lastname: Teixeira
authors.affiliation: Programa de Pós-Graduação em Saúde e Nutrição (PPGSN), School of Nutrition, University of Ouro Preto (UFOP), Minas Gerais, Brazil; Núcleo de Pesquisas em Ciências Biológicas (NUPEB), University of Ouro Preto (UFOP), Minas Gerais, Brazil.
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Silva
authors.affiliation: Núcleo de Pesquisas em Ciências Biológicas (NUPEB), University of Ouro Preto (UFOP), Minas Gerais, Brazil.
authors.forename: Wanderson G
authors.initials: WG
authors.lastname: de Lima
authors.affiliation: Programa de Pós-Graduação em Saúde e Nutrição (PPGSN), School of Nutrition, University of Ouro Preto (UFOP), Minas Gerais, Brazil; Núcleo de Pesquisas em Ciências Biológicas (NUPEB), University of Ouro Preto (UFOP), Minas Gerais, Brazil.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Pedrosa
authors.affiliation: Núcleo de Pesquisas em Ciências Biológicas (NUPEB), University of Ouro Preto (UFOP), Minas Gerais, Brazil; Programa de Pós-Graduação em Nutrição e Saúde (PPGNS), Departamento de Educação Integrada em Saúde (DEIS), University of Espírito Santo (UFES), Espírito Santo, Brazil. Electronic address: fabianokenji@gmail.com.
authors.forename: Fabiano K
authors.initials: FK
authors.lastname: Haraguchi
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D015536:Down-Regulation; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D008297:Male; D009068:Movement; D018482:Muscle, Skeletal / Q000187:drug effects*; D009929:Organ Size; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010586:Phagocytes / Q000187:drug effects; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology*; D050050:Protein Carbonylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D011916:Rats, Inbred F344; D055070:Resistance Training; D013482:Superoxide Dismutase / Q000378:metabolism; D015430:Weight Gain; D000067816:Whey Proteins / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D000067816:Whey Proteins; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione
keywords: Catalase; Gamma-glutamylcysteine synthetase; Glutathione peroxidase; Muscle growth; Rat; Superoxide dismutase