Citoproteção e inflamação: efeitos da suplementação com glutamina e alanina sobre a lesão muscular induzida pelo exercício resistido

RESUMO Exercícios de alta intensidade reduzem a concentração do aminoácido mais abundante do organismo, a glutamina, fato que pode influenciar na recuperação de atletas. Estudos demonstram que a suplementação oral crônica com L-glutamina na forma livre, em conjunto com L-alanina, ou como dipeptídeo (L-alanil-L-glutamina) pode atenuar a lesão, inflamação e imunossupressão induzida pelo exercício aeróbio intenso e/ou exaustivo. Contudo, o efeito destas suplementações durante o exercício resistido não é bem esclarecido. Nesse sentido, o objetivo do presente estudo foi revisar os efeitos da suplementação com L-glutamina e L-alanina sobre mecanismos de lesão muscular, inflamação e citoproteção induzidos pelo exercício resistido. ABSTRACT Cytoprotection and inflammation: effects of glutamine and alanine supplementation upon resistance exercise-induced muscle damageHigh intensity exercise reduces the levels of the most abundant amino acid in the body, glutamine, which may affect the recovery of athletes. Previous studies have shown that chronic oral supplementation with L-glutamine and L-alanine in its free form or as dipeptide (L-alanyl-L-glutamine) can attenuate the injury, inflammation and immune suppression induced by intense aerobic and exhaustive exercise. However, the effects of these supplements on resistance exercise are unclear. Thus, the aim of study was summarize the effect of L-glutamine and L-alanine upon muscle injury and inflammation in resistance exercise

Determination of the anti-inflammatory and cytoprotective effects of l-glutamine and l-alanine, or dipeptide, supplementation in rats submitted to resistance exercise

We evaluated the effects of chronic oral supplementation with l-glutamine and l-alanine in their free form or as the dipeptide l-alanyl-l-glutamine (DIP) on muscle damage, inflammation and cytoprotection, in rats submitted to progressive resistance exercise (RE). Wistar rats (n 8/group) were submitted to 8-week RE, which consisted of climbing a ladder with progressive loads. In the final 21 d before euthanasia, supplements were delivered in a 4 % solution in drinking water. Glutamine, creatine kinase (CK), lactate dehydrogenase (LDH), TNF-α, specific IL (IL-1β, IL-6 and IL-10) and monocyte chemoattractant protein-1 (MCP-1) levels were evaluated in plasma. The concentrations of glutamine, TNF-α, IL-6 and IL-10, as well as NF-κB activation, were determined in extensor digitorum longus (EDL) skeletal muscle. HSP70 level was assayed in EDL and peripheral blood mononuclear cells (PBMC). RE reduced glutamine concentration in plasma and EDL (P<0·05 v. sedentary group). However, l-glutamine supplements (l-alanine plus l-glutamine (GLN+ALA) and DIP groups) restored glutamine levels in plasma (by 40 and 58 %, respectively) and muscle (by 93 and 105 %, respectively). GLN+ALA and DIP groups also exhibited increased level of HSP70 in EDL and PBMC, consistent with the reduction of NF-κB p65 activation and cytokines in EDL. Muscle protection was also indicated by attenuation in plasma levels of CK, LDH, TNF-α and IL-1β, as well as an increase in IL-6, IL-10 and MCP-1. Our study demonstrates that chronic oral l-glutamine treatment (given with l-alanine or as dipeptide) following progressive RE induces cyprotective effects mediated by HSP70-associated responses to muscle damage and inflammation

Efeitos da suplementação com glutamina e alanina, na forma livre ou como dipeptídeo, sobre parâmetros de fadiga de ratos submetidos ao treinamento resistido

Fatigue is defined as the inability to maintain muscle power and strength, impairing performance. Nutritional interventions have been used to delay this phenomenon, such as glutamine and alanine supplementation. These amino acids might attenuate several causes of fatigue, since they are important energy substrates, transport ammonia avoiding the accumulation of this toxic metabolite and attenuate muscle damage and oxidative stress. Thus, the aim of this study was to evaluate the effects of glutamine and alanine supplementation on central and muscle fatigue parameters of rats submitted to resistance training (RT). Forty adult Wistar rats (60 days) were distributed into five groups: SED (sedentary, receiving water), CON (trained, receiving water), ALA, G+A and DIP (trained and supplemented with alanine, glutamine and alanine in their free form, and Lalanyl-L-glutamine, respectively). Trained groups underwent a ladder-climbing exercise, with progressive loads, for eight weeks. Supplements were diluted in water to a 4% concentration and offered ad libitum during the last 21 days of experiment. RT increased plasma glucose, the muscle concentrations of ammonia and glutathione (GSH) and the muscle damage parameters - plasma creatine kinase (CK) and lactate dehydrogenase (LDH), whereas decreased muscle glycogen. G+A supplementation prevented the increase of muscle ammonia by RT, while ALA and G+A administration reduced plasma CK and LDH, and DIP supplementation increased the muscle content of glycogen and LDH. Contrary to expectations, DIP administration increased central fatigue parameters, such as plasma concentration of free fatty acids (FFA), hypothalamic content of serotonin and serotonin/dopamine ratio. Despite these results, there was no difference between groups in the maximum carrying capacity (MCC) tests. In conclusion, supplementation with glutamine and alanine improves some fatigue parameters, but does not affect physical performance of rats submitted to RTO termo fadiga é definido como a incapacidade de manutenção da força e da potência musculares, prejudicando a performance. Intervenções nutricionais têm sido utilizadas para retardar este fenômeno, como a suplementação com glutamina e alanina. Estes aminoácidos poderiam atenuar diversas causas de fadiga, pois são importantes substratos energéticos, carreiam amônia evitando o acúmulo deste metabólito tóxico e atenuam a lesão muscular e o estresse oxidativo. Logo, o objetivo deste estudo foi avaliar os efeitos da suplementação com glutamina e alanina sobre parâmetros de fadiga central e muscular em ratos submetidos ao treinamento resistido (TR). Foram utilizados 40 ratos Wistar adultos (60 dias de idade), distribuídos nos grupos: SED (não treinados, recebendo água), CON (treinados, recebendo água), ALA, G+A e DIP (treinados e suplementados com alanina, glutamina e alanina livres, e L-alanil-L-glutamina, respectivamente). Os grupos treinados realizaram um exercício de escalada em escada, com aumento progressivo de carga, durante oito semanas. A suplementação foi diluída a 4% em água e ofertada via oral, ad libitum, durante os últimos 21 dias de experimento. O TR aumentou a glicemia, as concentrações musculares de amônia e de glutationa (GSH) e os parâmetros de lesão muscular - creatina quinase (CK) e lactato desidrogenase (LDH) no plasma, enquanto reduziu o glicogênio no músculo. A suplementação com G+A preveniu o aumento de amônia muscular promovido pelo TR, enquanto a administração de ALA e G+A reduziu as concentrações de CK e LDH no plasma, e a suplementação com DIP aumentou o conteúdo muscular de glicogênio e de LDH. Ao contrário do esperado, a administração de DIP aumentou parâmetros de fadiga central, como as concentrações plasmáticas de ácidos graxos livres, o conteúdo hipotalâmico de serotonina e a razão serotonina/dopamina. Apesar disso, não houve diferença entre os grupos nos testes de carga máxima. Em conclusão, a suplementação com glutamina e alanina melhora alguns parâmetros de fadiga, mas não afeta o desempenho físico em ratos submetidos ao TR

Glutamine as an Anti-Fatigue Amino Acid in Sports Nutrition

Glutamine is a conditionally essential amino acid widely used in sports nutrition, especially because of its immunomodulatory role. Notwithstanding, glutamine plays several other biological functions, such as cell proliferation, energy production, glycogenesis, ammonia buffering, maintenance of the acid-base balance, among others. Thus, this amino acid began to be investigated in sports nutrition beyond its effect on the immune system, attributing to glutamine various properties, such as an anti-fatigue role. Considering that the ergogenic potential of this amino acid is still not completely known, this review aimed to address the main properties by which glutamine could delay fatigue, as well as the effects of glutamine supplementation, alone or associated with other nutrients, on fatigue markers and performance in the context of physical exercise. PubMed database was selected to examine the literature, using the keywords combination &#8220;glutamine&#8222; and &#8220;fatigue&#8222;. Fifty-five studies met the inclusion criteria and were evaluated in this integrative literature review. Most of the studies evaluated observed that glutamine supplementation improved some fatigue markers, such as increased glycogen synthesis and reduced ammonia accumulation, but this intervention did not increase physical performance. Thus, despite improving some fatigue parameters, glutamine supplementation seems to have limited effects on performance

Effects of supplementation with L-glutamine and L-alanine in the body composition of rats submitted to resistance exercise

Abstract We investigated the effects of glutamine and alanine supplementation on body composition of rats submitted to resistance exercise. Wistar rats were submitted to eight-week of resistance exercise, which consisted of climbing a ladder with progressive loads (25–100% of body weight). In the last 21 days of training, animals were supplemented with L-glutamine and L-alanine, as a dipeptide or in their free form (DIP, GLN + ALA and ALA groups), or water (SED and CTRL groups). RE attenuated body weight gain and lipid contents of CTRL group (p < 0.05 vs. SED) and DIP supplementation promoted an increase in tibialis muscle weight, as well as in protein content (p < 0.05 vs. CTRL). Taken together, our data indicated that resistance exercise improves body composition and dipeptide potentiated the muscle hypertrophic effect

Creatina como antioxidante em estados metabólicos envolvendo estresse oxidativo

O estresse oxidativo decorre do desequilíbrio entre oxidantes e antioxidantes. A síntese de oxidantes é mais acentuada no exercício físico intenso, pois a demanda energética é aumentada. A creatina tem sido apontada como um antioxidante, pois é essencial para manutenção da homeostase energética e apresenta arginina em sua estrutura molecular, entretanto, os dados apresentados na literatura são contraditórios. O objetivo do presente trabalho foi sintetizar o conhecimento disponível a respeito do papel antioxidante da creatina no contexto do esporte e em estados metabólicos envolvendo o estresse oxidativo. Realizou-se uma revisão bibliográfica, sem limitação quanto ao período de publicação. Os estudos revisados, em sua maioria, apresentam efeitos antioxidantes com ação direta, indireta ou ambas, relacionados às intervenções com creatina, entretanto a escolha do tipo amostral e protocolo experimental influenciou nos resultados. Conclui-se que a creatina apresenta atividade antioxidante, porém este efeito é dependente das condições em que o recurso é empregado. ABSTRACT Creatine as an antioxidant in metabolic states linked to oxidative stressThe oxidative stress results from an imbalance between oxidants and antioxidants. The synthesis of oxidants is more pronounced in intense physical exercise, since the energy demand is increased. Creatine has been identified as an antioxidant, since it is essential to maintaining energy homeostasis, and presents arginine in its molecular structure, however, the data presented in the literature are contradictory. The objective of this study was to synthesize the knowledge available about the antioxidant role of creatine in the context of sport and metabolic conditions involving oxidative stress. We carried out a literature review, without limitation the publication period. The mostly studies reviewed presented antioxidant effects with direct action, indirect or both, related to interventions with creatine, however the choice of sample type and experimental protocol influenced the results.  It was concluded that creatine has antioxidant activity, but this effect is dependent on the conditions which the resource is used

Citoproteção e inflamação: efeitos da suplementação com glutamina e alanina sobre a lesão muscular induzida pelo exercício resistido

Exercícios de alta intensidade reduzem a concentração do aminoácido mais abundante do organismo, a glutamina, fato que pode influenciar na recuperação de atletas. Estudos demonstram que a suplementação oral crônica com L-glutamina na forma livre, em conjunto com L-alanina, ou como dipeptídeo (L-alanil-L-glutamina) pode atenuar a lesão, inflamação e imunossupressão induzida pelo exercício aeróbio intenso e/ou exaustivo. Contudo, o efeito destas suplementações durante o exercício resistido não é bem esclarecido. Nesse sentido, o objetivo do presente estudo foi revisar os efeitos da suplementação com L-glutamina e L-alanina sobre mecanismos de lesão muscular, inflamação e citoproteção induzidos pelo exercício resistido.High intensity exercise reduces the levels of the most abundant amino acid in the body, glutamine, which may affect the recovery of athletes. Previous studies have shown that chronic oral supplementation with L-glutamine and L-alanine in its free form or as dipeptide (L-alanyl-L-glutamine) can attenuate the injury, inflammation and immune suppression induced by intense aerobic and exhaustive exercise. However, the effects of these supplements on resistance exercise are unclear. Thus, the aim of study was summarize the effect of L-glutamine and L-alanine upon muscle injury and inflammation in resistance exercise

Insatisfação corporal em atletas de Voleibol feminino

Body dissatisfaction in female volleyball athletesThe body dissatisfaction during adolescence is very common, and girls, especially athletes, are the most affected, with beauty standards imposed by society, in which the thinness is seen as a goal to be achieved. The aim of this study was to evaluate the perception of self-image and body dissatisfaction in young female volleyball athletes. The sample consisted of 34 young competitive volleyball players, aged 11-18 years, from a club in São Paulo. It was applied the test: "Body Shape Questionnaire" (BSQ) and the "Silhouettes of Stunkard" for evaluation the body dissatisfaction. After filling out the questionnaires, the height, the weight, the bioimpedance and the seven skinfolds were measured. The results obtained through the BSQ questionnaire indicate the absence of body dissatisfaction in pre-mirim group, light in mirim and infant, and moderate in infantile group. Referring to the "Silhouettes of Stunkard", the results indicate that 85% of athletes are dissatisfied with their body image, indicating a pursuit of thinness in all groups. We concluded that most of the athletes demonstrated some degree of body dissatisfaction, especially between 15 and 16 years. Nutritional monitoring is necessary to adjust the nutritional status, reduce body image dissatisfaction and minimize the risk of developing eating disorders.A insatisfação corporal na adolescência é muito comum, sendo que as meninas, especialmente atletas, são as mais afetadas, com padrões de beleza impostos pela sociedade, nos quais a magreza é vista como uma meta a ser alcançada. O objetivo deste estudo foi avaliar a percepção da auto-imagem e de insatisfação corporal em jovens atletas de voleibol feminino. A amostra foi composta por 34 atletas adolescentes competitivas de voleibol, com idades entre 11 a 18 anos, de um clube da cidade de São Paulo. Foi aplicado um teste de autopreenchimento: “Body Shape Questionnaire” (BSQ) e as “Silhuetas de Stunkard” para avaliação da insatisfação corporal. Após o preenchimento dos questionários, foram aferidas a estatura, o peso, a bioimpedância e as sete dobras cutâneas. Os resultados obtidos através do questionário BSQ indicam ausência de insatisfação corporal no grupo pré-mirim, leve no mirim e no infanto, e moderada no infantil. Referente às Silhuetas de Stunkard, os resultados obtidos indicam que 85% das atletas apresentaram-se insatisfeitas com a imagem corporal, evidenciando uma busca à magreza em todos os grupos estudados. Conclui-se que a maioria das atletas demonstrou algum grau de insatisfação corporal, sobretudo, entre 15 e 16 anos. O acompanhamento nutricional é necessário para adequar o estado nutricional, reduzir a insatisfação de imagem corporal e minimizar o risco de desenvolvimento de transtornos alimentares.

Effects of Glutamine and Alanine Supplementation on Central Fatigue Markers in Rats Submitted to Resistance Training

Recent evidence suggests that increased brain serotonin synthesis impairs performance in high-intensity intermittent exercise and specific amino acids may modulate this condition, delaying fatigue. This study investigated the effects of glutamine and alanine supplementation on central fatigue markers in rats submitted to resistance training (RT). Wistar rats were distributed in: sedentary (SED), trained (CON), trained and supplemented with alanine (ALA), glutamine and alanine in their free form (G + A), or as dipeptide (DIP). Trained groups underwent a ladder-climbing exercise for eight weeks, with progressive loads. In the last 21 days, supplementations were offered in water with a 4% concentration. Albeit without statistically significance difference, RT decreased liver glycogen, and enhanced the concentrations of plasma glucose, free fatty acids (FFA), hypothalamic serotonin, and ammonia in muscle and the liver. Amino acids affected fatigue parameters depending on the supplementation form. G + A prevented the muscle ammonia increase by RT, whereas ALA and DIP augmented ammonia and glycogen concentrations in muscle. DIP also increased liver ammonia. ALA and G + A reduced plasma FFA, whereas DIP increased this parameter, free tryptophan/total tryptophan ratio, hypothalamic serotonin, and the serotonin/dopamine ratio. The supplementations did not affect physical performance. In conclusion, glutamine and alanine may improve or impair central fatigue markers depending on their supplementation form