Effects of glutamine and alanine supplementation, in their free form or as dipeptide, on fatigue parameters of rats submitted to resistance training / 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 RT

O 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

Probiotic supplementation in dental caries: is it possible to replace conventional treatment?

BACKGROUND: Probiotic supplementation alters oral microbiota composition and could reduce the risk or treat oral cavity diseases, such as dental caries, which are considered a public health problem. Aim: To summarize the therapeutic effects of probiotics in caries and to verify whether this intervention is capable of replacing conventional treatment in human beings. METHODS: he search of the studies was carried out in the PubMed database in October 2017, without limiting the publication period. The keyword combination used was "Probiotics" and "Dental caries." Forty-two original articles that evaluated the effect of probiotic supplementation on caries treatment in humans were included in the study. RESULTS: Most of the studies evaluated bacteria of the genus Lactobacillus. The main therapeutic effects are related to the reduction of the Streptococcus mutans oral count, increased Lactobacillus oral count, and reduction in the incidence of caries. Evidence on the therapeutic effects of the Bifidobacterium and Streptococcus genres is scarce and conflicting, making it difficult to recommend them for use in clinical practice. Only a few studies administered probiotics without conventional treatments, such as fluoride. Although probiotic supplementation presented interesting properties, the therapeutic effects are more pronounced when probiotic and fluoride are applied together. CONCLUSION: Probiotics, especially of the Lactobacillus genus, can be used as adjuvants, but cannot replace the conventional treatments of caries.

Effects of supplementation with L-glutamine and L-alanine in the body composition of rats submitted to resistance exercise / Efeitos da suplementação com L-glutamina e L-alanina na composição corporal de ratos submetidos ao exercício resistido / Efectos de la suplementación con L-glutamina y L-alanina en la composición corporal de ratones sometidos a ejercicio de resistencia

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.

Resumo Foram investigados os efeitos da suplementação com glutamina e alanina na composição corporal de ratos submetidos a exercício resistido. Ratos Wistar foram submetidos, durante oito semanas, ao exercício resistido, que consistia em subir uma escada com cargas progressivas (25 a 100% do peso corporal). Nos últimos 21 dias de treinamento, os animais foram suplementados com L-glutamina e L-alanina, como dipeptídeo ou em sua forma livre (DIP, GLN + ALA ALA e grupos) ou água (grupos SED e CTRL). Exercício resistido atenuou o ganho de peso corporal e conteúdo lipídico do CTRL (p < 0,05 vs. SED) e o DIP promoveu aumento no peso do músculo tibial, bem como no teor de proteína (p < 0,05 vs. CTRL). Os nossos dados indicam que o exercício resistido, melhora a composição corporal e dipeptídeo potencializa o efeito hipertrófico muscular.

Resumen Se investigaron los efectos de la glutamina y la alanina en la composición corporal de ratones sometidos a ejercicio de resistencia. Algunos ratones Wistar fueron sometidos a 8 semanas de ejercicio de resistencia, que consistía en subir una escalera con cargas progresivas (del 25 al 100% de la masa corporal). En los últimos 21 días, los animales recibieron un suplemento de L-glutamina y L-alanina, en forma de dipéptido o en su forma libre (grupos DIP, GLN + ALA y ALA) o agua (grupos SED y CTRL). El ejercicio de resistencia redujo el aumento de masa corporal y la concentración de lípidos del CTRL (p <0,05 vs. SED). La suplementación con DIP promovió un aumento de peso del músculo tibial, así como en el contenido de proteína (p < 0,05 frente a CTRL). Nuestros resultados indican que el ejercicio de resistencia mejora la composición corporal y el DIP potencia el efecto hipertrófico.