Effect of Liposomal Protium heptaphyllum (Alb.) March Extract in the Treatment of Obesity Induced by High-Calorie Diet.

Obesity, a chronic disease, resulted from excessive consumption of high-calorie foods, leading to an energy imbalance. Protium heptaphyllum (P. heptaphyllum) was used in folk medicine for its analgesic, anti-inflammatory, and healing properties. The association of the extract from P. heptaphyllum with nanotechnology was innovative for combining high technology with active ingredients that are easily accessible in the Amazon region. This study evaluated the effect of liposomes containing the ethyl acetate fraction of the crude extract of P. heptaphyllum leaves on obesity. Male Wistar rats treated with a high-calorie diet for 8 weeks to induce obesity received treatment with the liposome formulation containing P. heptaphyllum extract (1 mg/kg/day, via gavage) for 14 days. Morphological, metabolic, redox status, immunological, and histological parameters were evaluated in the adipose and liver tissue of the animals. The groups were divided as follows: C: control; P: liposomes containing extract; O: obese, and OP: obese + liposomes containing extract. The obesity model resulted in increases in body weight, caloric intake, body fat weight, and in the lipid profile. In adipose tissue, P decreased SOD (superoxide dismutase) activity in obese animals. In the liver, a positive modulation of the extract was observed in relation to glucose, amino acids, lactate, hepatoprotective action, and anti-inflammatory activity, with a decrease in interleukin 1ß (IL-1ß) in obese animals. The results showed an improvement in the functional and inflammatory aspects, but the treatment was not effective in alleviating general changes related to obesity, such as weight gain, fat, glucose, triglycerides, and inflammation in adipose tissue, highlighting the complexity of responses in different organs during obesity and treatment with P. heptaphyllum.

Effects of Vitamin D on Cardiovascular Risk and Oxidative Stress.

INTRODUCTION: Vitamin D has been primarily studied as an important factor influencing bone and calcium metabolism. Metabolites of vitamin D are essential for whole-body calcium homeostasis, maintaining serum calcium levels within a narrow range by regulating this process in the bones and gut. Nevertheless, its deficiency is also related to increased risk of type 2 diabetes mellitus (T2DM), metabolic syndrome (MS), and cardiovascular disease (CVD)-with increased visceral adipose tissue and body mass index (BMI), as well as the frequently associated hypercholesterolemia. It has been reported that vitamin D levels are inversely related to cardiovascular (CV) risk in men and women. However, the effects of vitamin D on distinct outcomes in women and the dose of supplementation needed to improve clinical endpoints have not been established. 25-Hydroxyvitamin D [25(OH)D] reduces systemic inflammatory mediators in CVD and favors the release of anti-inflammatory cytokines from the immune system. In addition, 25(OH)D can be primarily converted into calcitriol (1,25-dihydroxycholecalciferol [1,25(OH)2D]) in the kidneys through the action of the 1-α-hydroxylase enzyme. Calcitriol, through the downregulation mechanism of renin expression, renin-angiotensin-aldosterone system (RAAS) activity, and its interaction with the vitamin D receptor, can bring CV benefits. The calcitriol form also lowers parathyroid hormone (PTH) levels by indirectly causing a reduction in aldosterone and mineralocorticoid synthesis. Elevated plasma aldosterone is related to endothelial dysfunction and CVD in hypovitaminosis D status. CONCLUSION: Vitamin D supplementation may benefit certain risk groups, as it improves metabolic variables, reducing oxidative stress and CV outcomes. More studies are needed to define interventions with vitamin D in men and women.

Anti ige na asma grave 'relato de caso' / Anti ige in severe asthma 'case report / Anti ige en el asma grave 'informe de un caso

A asma grave é uma doença respiratória crônica que afeta as vias aéreas, provocando inflamação e estreitamento dos brônquios. Esse estreitamento pode dificultar a respiração e causar sintomas como tosse, falta de ar, chiado no peito e aperto no peito. Quando a asma não é controlada adequadamente com medicamentos e outras medidas, ela pode evoluir para um quadro de asma grave. O presente artigo científico consiste em uma revisão literária sobre o tratamento da asma grave com elevados níveis de anticorpos IgE por meio do uso do anticorpo monoclonal Omalizumabe, além de apresentar o relato de caso observacional em um paciente pediátrico atendido em um consultório especializado da cidade de Mineiros no estado de Goiás. Os estudos revisados demonstraram que a terapia com Omalizumabe pode melhorar a função pulmonar, reduzir a necessidade de medicação de resgate e melhorar a qualidade de vida em pacientes com asma grave. No entanto, também foi observado que o benefício do Omalizumabe é mais pronunciado em pacientes com níveis mais elevados de IgE e em pacientes que apresentam sintomas asmáticos frequentes. A revisão literária apresentou evidências consistentes de que o Omalizumabe é uma opção terapêutica eficaz e segura para o tratamento de asma grave com elevados níveis de IgE em pacientes pediátricos. Por fim com objetivo de fornecer informações importantes para médicos e profissionais de saúde sobre o uso do Omalizumabe no tratamento da asma grave em crianças, além de destacar a necessidade de mais pesquisas para avaliar a eficácia e segurança do medicamento em populações maiores e com seguimento mais prolongado.

Severe asthma is a chronic respiratory disease that affects the airways, causing inflammation and narrowing of the bronchi. This narrowing can make breathing difficult and cause symptoms such as coughing, shortness of breath, wheezing, and chest tightness. When asthma is not properly controlled with medication and other measures, it can develop into severe asthma. The present scientific article consists of a literature review on the treatment of severe asthma with high IgE antibody levels by the use of the monoclonal antibody Omalizumab, besides presenting the report of an observational case in a pediatric patient seen at a specialized clinic in the city of Mineiros in the state of Goiás. The studies reviewed showed that Omalizumab therapy can improve lung function, reduce the need for rescue medication, and improve quality of life in patients with severe asthma. However, it was also noted that the benefit of Omalizumab is more pronounced in patients with higher IgE levels and in patients who have frequent asthmatic symptoms. The literature review presented consistent evidence that Omalizumab is an effective and safe therapeutic option for the treatment of severe asthma with high IgE levels in pediatric patients. Finally with aim to provide important information for physicians and health care professionals about the use of Omalizumab in the treatment of severe asthma in children, and to highlight the need for further research to evaluate the efficacy and safety of the drug in larger populations and with longer follow-up.

El asma grave es una enfermedad respiratoria crónica que afecta a las vías respiratorias, causando inflamación y estrechamiento de los bronquios. Este estrechamiento puede dificultar la respiración y causar síntomas como tos, falta de aire, sibilancias y opresión torácica. Cuando el asma no se controla adecuadamente con medicación y otras medidas, puede convertirse en asma grave. El presente artículo científico consiste en una revisión bibliográfica sobre el tratamiento del asma grave con niveles elevados de anticuerpos IgE mediante el uso del anticuerpo monoclonal Omalizumab, además de presentar el informe de un caso observacional en un paciente pediátrico atendido en una clínica especializada de la ciudad de Mineiros, en el estado de Goiás. Los estudios revisados demostraron que el tratamiento con omalizumab puede mejorar la función pulmonar, reducir la necesidad de medicación de rescate y mejorar la calidad de vida en pacientes con asma grave. Sin embargo, también se observó que el beneficio del omalizumab es más pronunciado en pacientes con niveles más altos de IgE y en pacientes que presentan síntomas asmáticos frecuentes. La revisión bibliográfica presentó pruebas consistentes de que omalizumab es una opción terapéutica eficaz y segura para el tratamiento del asma grave con niveles elevados de IgE en pacientes pediátricos. Finalmente con el objetivo de proporcionar información importante para los médicos y profesionales de la salud sobre el uso de Omalizumab en el tratamiento del asma grave en niños, así como destacar la necesidad de nuevas investigaciones para evaluar la eficacia y seguridad del fármaco en poblaciones más grandes y con un seguimiento más prolongado.

Extubação paliativa: reflexões bioéticas sobre cuidados em fim de vida / Palliative extubation: bioethical reflections on end-of-life care / Extubación paliativa: reflexiones bioéticas sobre los cuidados al final de la vida

Resumo Cuidados paliativos integram um conjunto de abordagens que objetivam incrementar a qualidade de vida diante de uma doença incurável e potencialmente ameaçadora para a vida. Nesse cenário, dentre as terapêuticas utilizadas no cuidado a pacientes críticos, a extubação paliativa é implementada quando as tentativas de desmame da ventilação mecânica falharam, a fim de evitar o prolongamento da vida a qualquer custo. Mesmo com o limitado número de pesquisas sobre o assunto, importantes debates têm emergido no campo biomédico, ético, religioso e legal, trazendo novas reflexões sobre o tema. No Brasil, ainda há muitos entraves para o procedimento, o que inspira o debate bioético.

Abstract Palliative care is part of a set of approaches aimed at improving quality of life in the face of an incurable and potentially life-threatening disease. In this context, among the therapies for critically ill patients, palliative extubation is performed when all attempts of withdrawing mechanical ventilation have failed, an alternative to avoid prolonging life at any cost. Despite the limited number of studies published on the subject, important biomedical, ethical, religious and legal discussions have emerged, bringing new reflections on the theme. In Brazil, the procedure still faces many obstacles, making it an inspiring subject for bioethical discussions.

Resumen Los cuidados paliativos integran un conjunto de enfoques dirigidos a aumentar la calidad de vida ante una enfermedad incurable y potencialmente amenazadora para la vida. En este escenario, entre las terapéuticas utilizadas en el cuidado a pacientes críticos, la extubación paliativa se implementa cuando los intentos de destete de la ventilación mecánica fallan, con el objetivo de evitar prolongar la vida a toda costa. Incluso con el limitado número de investigaciones sobre el asunto, han surgido debates importantes en los campos biomédico, ético, religioso y legal, aportando nuevas reflexiones sobre el tema. En Brasil, aún hay muchos obstáculos frente a este procedimiento, lo que inspira el debate bioético.

High sucrose diet attenuates oxidative stress, inflammation and liver injury in thioacetamide-induced liver cirrhosis.

AIMS: Liver cirrhosis is the main chronic liver disease and is considered a catabolic disease. Cirrhotic patients have a low energy intake and high energy expenditure at rest, leading to metabolic disorders. Malnutrition is associated with complications of cirrhosis and has been shown that a nutritional intervention with increase of energy intake improves the survival of cirrhotic patients. Therefore, our aim was to evaluate the effect of a high sucrose diet in the liver of animals with cirrhosis induced by thioacetamide and investigate the mechanism involved. MAIN METHODS: Male Wistar rats were divided into three groups: Control; Thioacetamide; and Thioacetamide + high sucrose diet. The thioacetamide was administrated (100 mg kg-1) intraperitoneally and the sucrose was offered in drinking water (300 g L-1). KEY FINDINGS: The administration of thioacetamide was associated with fibrosis and inflammatory infiltrate in the liver and increased levels of transaminases enzymes. The high sucrose diet promoted a reduction of theses parameters in cirrhotic rats. The malnutrition observed in cirrhotic rats was attenuated by the high sucrose diet shown by the improvements in weight loss, subcutaneous fat, and caloric intake. The high sucrose diet also attenuated the oxidative stress present in the liver of animals with thioacetamide-induced cirrhosis. SIGNIFICANCE: The high sucrose diet had anti-inflammatory and anti-oxidant effects in the liver of animals with thioacetamide-induced cirrhosis. In addition, the high sucrose diet also improved malnutrition and catabolism present in cirrhosis. Thus, a high sucrose diet may be a therapeutic option for cirrhotic patients in a catabolic state.

Antioxidant potential of Carica papaya Linn (Caricaceae) leaf extract in mice with cyclophosphamide induced oxidative stress / Potencial antioxidante do extrato de folhas de Carica papaya Linn (Caricaceae) em camundongos com estresse oxidativo induzido por ciclofosfamida

AIMS: This study aimed to investigate the effects of crude extract of Carica papaya leaves on oxidative stress in mice induced by cyclophosphamide, as well as phytochemical profile characterization of this extract. METHODS: The male Swiss mice received 15 days of treatment with the extract (500 mg kg-1, via gavage) and intraperitoneal injection of cyclophosphamide (75 mg kg-1) or saline (0.9%) on the 15th day. After 24 h the last treatment, the animals were anesthetized for blood withdrawal, sacrificed and removal of the organs for analyses (liver, kidney and heart). In the biochemical tests were determined: hematological parameters in blood, aminotransferases, alkaline phosphatase, glucose and total cholesterol dosages in plasma, enzymatic and non-enzymatic antioxidants and lipid damage marker were evaluated in different tissues, besides genotoxic and histopathological analyzes. RESULTS: In the extract of Carica papaya leaves, the flavonoids quercetin-3ß-D-glucoside and rutin were identified, besides present positive results for alkaloids, saponins and tannins. This extract increased the activity of glutathione-S-transferase and catalase enzymes in the liver and reduced the levels of reduced glutathione in the kidneys and hematocrit levels, red cell count, and hemoglobin. It promoted the decrease of the reactive species of thiobarbituric acid (TBARS) in the kidneys and the activity of enzyme aspartate aminotransferase in the plasma and was antimutagenic in the micronucleus test. CONCLUSIONS: The study showed that extract of Carica papaya was beneficial against oxidative events and prevented DNA damage. The extract also showed hepatotoxicity, therefore prolonged infusion of papaya leaves is not advisable.

OBJETIVOS: O objetivo deste estudo foi investigar os efeitos do extrato bruto de folhas de Carica papaya sobre o estresse oxidativo em camundongos induzidos pela ciclofosfamida, bem como a caracterização do perfil fitoquímico deste extrato. MÉTODOS: Os camundongos Swiss machos receberam 15 dias de tratamento com o extrato (500 mg kg-1, via gavagem) e injeção intraperitoneal de ciclofos-famida (75 mg kg-1) ou salina (0,9%) no 15º dia. Após 24 h do último tratamento, os animais foram anestesiados para retirada do sangue, sacrificados e retirada dos órgãos para análises (fígado, rim e coração). Nos testes bioquímicos foram determinados: parâmetros hematológicos em sangue, aminotransferases, fosfatase alcalina, dosagens de glicose e colesterol total no plasma, antioxidantes enzimáticos e não enzimáticos e marcador de dano lipídico foram avaliados em diferentes tecidos, além de análises genotóxicas e histopatológicas. RESULTADOS: No extrato de folhas de Carica papaya foram identificados os flavonoides quercetina-3ß-D-glicosídeo e rutina, além de resultados positivos para alcaloides, saponinas e taninos. Este extrato aumentou a atividade das enzimas glutationa-S-transferase e catalase no fígado e diminuiu os níveis de glutationa reduzida nos rins, a concentração do hematócrito, a contagem dos glóbulos vermelhos e a hemoglobina. Promoveu a diminuição das espécies reativas de ácido tiobarbitúrico (TBARS) nos rins, a atividade da enzima aspartato aminotransferase no plasma e foi antimuta-gênico no teste do micronúcleo. CONCLUSÕES: O estudo mostrou que o extrato de Carica papaya foi benéfico contra eventos oxidativos e preveniu danos no DNA. O extrato também mostrou hepatotoxicidade, portanto, a infusão prolongada de folhas de mamão não é aconselhável.

Effects of glyphosate-based herbicide on pintado da Amazônia: Hematology, histological aspects, metabolic parameters and genotoxic potential.

Roundup Original® is an herbicide widely used in Mato Grosso's agriculture and it may contamine water bodies, being an unforeseen xenobiotic to aquatic organisms, particularly fish. This study investigated the effects on the hybrid fish jundiara (Leiarius marmoratus×Pseudoplatystoma reticulatum) of an environmentally relevant exposure to this herbicide. Glucose levels in liver, muscle and plasma decreased after exposure to 1.357mgL-1 of Roundup Original® (glyphosate nominal concentration), while glycogen levels reduced in liver and muscle for different times. Elevated cholesterol and triglycerides revealed an adaptive response. Protein and lactate levels also increased during the experiment, however no changes were observed for muscle lactate. Increment of the transaminases suggests damage to the liver cells. After 96hours of exposure, reductions in all hematological parameters were observed, whereas the micronucleus test findings showed genotoxic scenery. Histological analysis did not display pathological alterations of the hepatic tissue. The results obtained provide valuable data for noticing the effects of pollutants on non-target organisms.

Digoxin Induces Cardiac Hypertrophy Without Negative Effects on Cardiac Function and Physical Performance in Trained Normotensive Rats.

Cardiotonic drugs and exercise training promote cardiac inotropic effects, which may affect training-induced cardiac adaptations. This study investigated the effects of long-term administration of digoxin on heart structure and function, and physical performance of rats submitted to high-intensity interval training (HIIT). Male Wistar rats, 60 days old, were divided into control (C), digoxin (DIGO), trained (T), and trained with digoxin (TDIGO). Digoxin was administered by gavage (30 µg/kg/day) for 75 days. The HIIT program consisted of treadmill running 60 min/day (8 min at 80% of the maximum speed (MS) and 2 min at 20% of the MS), 5 days per week during 60 days. The main cardiac parameters were evaluated by echocardiograph and cardiomyocyte area was determined by histology. There were no group x time effects of digoxin, HIIT or interactions (digoxin and HIIT) on functional echocardiographic parameters (heart rate; ejection fraction) or in the maximum exercise test. There was a group x time interaction, as evidenced by observed cardiac hypertrophy in the TDIGO group evaluated by ratio of left ventricle weight to body weight (p<0.002) and cardiomyocyte area (p<0.000002). Long-term administration of digoxin promoted cardiac hypertrophy without affecting cardiac function and physical performance in rats submitted to HIIT.

DIGOXINA E VERAPAMIL INDUZEM HIPERTROFIA EM CARDIOMIÓCITOS DE RATOS SEDENTÁRIOS E/OU TREINADOS / DIGOXIN AND VERAPAMIL PROMOTE CARDIOMYOCYTE HYPERTROPHY IN SEDENTARY AND/OR TRAINED RATS / DIGOXINA Y VERAPAMILO INDUCEN HIPERTROFIA DE CARDIOMIOCITOS EN RATAS SEDENTARIAS Y/O ENTRENADAS

RESUMO Introdução: Cardiotônicos e bloqueadores de canais de cálcio são fármacos que alteram o Ca2+ intracelular e afetam o coração. Objetivo: Avaliar os efeitos da administração de verapamil e digoxina sobre a morfologia cardíaca de ratos submetidos ao treinamento intervalado (TAI). Métodos: Ratos Wistar machos divididos em seis grupos (N = 8): Controle, Digoxina (30,0 µg.kg-1/dia), Verapamil (5,0 mg.kg-1/dia), Treinado, Treinado+digoxina e Treinado+verapamil. O TAI foi realizado em esteira rolante (60 min/dia/60 dias) concomitantemente com a administração dos fármacos. Fragmentos do ventrículo esquerdo (VE) foram coletados para análise histológica. Resultados: A digoxina e o verapamil aumentaram a área total do VE (p < 0,002), capilares/área VE (p < 0,01) e área de cardiomiócitos (p < 2,8e-10), sendo que, nesta última variável, o verapamil promoveu efeito ainda maior que a digoxina. O TAI aumentou VE/PC (p < 4e-05), o diâmetro interno do VE (p < 2,7e-6), a área de cardiomiócitos (p < 1,8e-6) e reduziu o [Lac] (p < 2,6e-5). Houve interação entre TAI e fármacos na área total (p < 9,8e-5), capilares (p < 0,04), células/área (p < 0,004) e área de cardiomiócitos (p < 2e-16). Conclusão: A digoxina promoveu hipertrofia de cardiomiócitos e, quando associada ao TAI, potencializou a hipertrofia. O verapamil foi mais eficiente em aumentar a área de cardiomiócitos em comparação com a digoxina, porém somente de forma isolada.

ABSTRACT Introduction: Cardiotonics and calcium channel blockers are drugs that alter intracellular Ca2+ and can affect the heart. Objective: To evaluate the effects of administration of verapamil and digoxin on heart morphology of rats subjected to interval training (IT). Methods: Male Wistar rats were divided into groups (n = 8): Control, Digoxin (30.0µg.kg-1/day), Verapamil (5.0 mg.kg-1/day), Trained, Trained+digoxin and Trained+verapamil. The IT was performed on a treadmill (60 min/day/60 days) concurrently with the drugs administration. Fragments of the left ventricle (LV) were collected for histological analysis. Results: Digoxin and verapamil increased the total area of the LV (p<0.002), capillary/LV area (p<0.01) and cardiomyocytes area (p<2.8e-10), and in the latter variable, verapamil promoted even greater effect than digoxin. The IT increased LV/BW (p<4e-05), the inner diameter of the LV (p<2.7e-6), the area of cardiomyocytes (p<1.8e-6), and reduced the [Lac] (p<2.6e-5). There was interaction between IT and drugs in the total area (p<9.8e-5), capillaries (p<0.04), cell/area (p<0.004) and cardiomyocytes area (p <2.0e-16). Conclusions: Digoxin promoted cardiomyocyte hypertrophy and when associated with IT, potentiated the hypertrophy. Verapamil was more efficient in increasing the cardiomyocytes area compared with digoxin, but only when isolated.

RESUMEN Introducción: Cardiotónicos y bloqueadores de los canales de calcio son fármacos que alteran el Ca2+ intracelular y afectan al corazón. Objetivo: Evaluar los efectos de la administración de verapamilo y digoxina sobre la morfología del corazón de ratas sometidas a entrenamiento a intervalos (EI). Métodos: Ratas Wistar macho, divididas en seis grupos (N = 8): Control, Digoxina (30,0 µg.kg-1/día), Verapamilo (5,0 mg.kg-1/día), Entrenado, Entrenado+digoxina y Entrenado+verapamilo. El entrenamiento a intervalos se realizó en una cinta de correr (60 min/día/60 días), con la administración concomitante de fármacos. Se recogieron fragmentos del ventrículo izquierdo (VI) para el análisis histológico. Resultados: La digoxina y el verapamilo aumentaron el área total del VI (p < 0,002), capilares/área VI (p < 0,01) y el área de los cardiomiocitos (p < 2,8e-10) y, en esta última variable, el verapamilo promovió un efecto aún mayor que la digoxina. EI entrenamiento a intervalos aumentó VI/PC (p < 4e-05), el diámetro interior del VI (p < 2,7e-6), el área de los cardiomiocitos (p < 1,8e-6) y redujo el [Lac] (p < 2,6e-5). Hubo una interacción entre fármacos y el EI en el área total (p < 9,8e-5), capilares (p<0,04), células/área (p < 0,004) y el área de los cardiomiocitos (p < 2e-16). Conclusión: La digoxina promovió la hipertrofia de los cardiomiocitos y, cuando al asociarse con el EI, potenció la hipertrofia. El verapamilo fue más eficiente en el aumento de la zona de los cardiomiocitos en comparación con la digoxina, pero sólo de forma aislada.

Creatine does not promote hypertrophy in skeletal muscle in supplemented compared with nonsupplemented rats subjected to a similar workload.

The purpose of this study was to test the hypothesis that creatine (Cr) supplementation may promote an additional hypertrophic effect on skeletal muscle independent of a higher workload on Cr-supplemented trained muscle compared with Cr-nonsupplemented trained muscle. Male Wistar rats (2-3 months old, 250-300 g) were divided randomly into 4 groups (n = 8 per group): nontrained without Cr supplementation (CO), nontrained with Cr supplementation (CR), trained without Cr supplementation (TR), and trained with Cr supplementation (TRCR). Creatine supplementation was given at 0.5 g/kg per day. Trained groups were submitted to a 5-week resistance training program (5 d/wk). The progressive workloads were similar between the Cr-supplemented (TRCR) and Cr-nonsupplemented (TR) trained groups; the only difference between groups was the Cr treatment. After the 5-week experiment, the soleus muscle was dissected to analyze the cross-sectional area (CSA) of the muscle fibers. Resistance training promoted a significant (P < .05) increase in the muscle fibers CSA in the TR group compared with the CO group. However, no additional hypertrophic effect was found when Cr supplementation was added to training (TRCR vs TR comparison, P > .05). In addition, Cr supplementation alone did not promote significant alterations in muscle fiber CSA (CR vs CO comparison, P > .05). We conclude that Cr supplementation does not promote any additional hypertrophic effect on skeletal muscle area when Cr-supplemented trained muscles are submitted to same training regimen than Cr-nonsupplemented trained muscles. Specifically, any benefits of Cr supplementation on hypertrophy gains during resistance training may not be attributed to a direct anabolic effect on the skeletal muscle.

Effects of creatine supplementation during resistance training on myosin heavy chain (MHC) expression in rat skeletal muscle fibers.

The purpose of this study was to utilize a rodent model to test the hypothesis that creatine (Cr) supplementation during resistance training would influence the pattern of slow-twitch muscle myosin heavy chain (MHC) isoforms expression. Male Wistar rats (2-3 months old, 250-300 g) were divided into 4 groups: Nontrained without creatine supplementation (CO), nontrained with creatine supplementation (CR), trained without creatine supplementation (TR), and trained with creatine supplementation (TRCR). TR and TRCR groups were submitted to a resistance training program for 5 weeks (5 days/week) for morphological and biochemical analysis of the soleus muscle. Weightlifting exercise involved jump sessions into water, carrying progressive overload equivalent to percentage of body weight. CR and TRCR groups were given creatine at 0.5 g/kg(-1)/d(-1). Both Cr supplementation and resistance training alone or associated did not result in significant alterations (p > 0.05) in body weight gain, food intake, and muscle weight in the CR, TR and TRCR groups compared to the CO group. Also compared to the CO group, the CR group showed a significant (p < 0.02) increase in MHCI content and a reduction in MHCII; inversely, the TR group increased the MHCII content and reduced MHCI (p < 0.02). When combined, both creatine and resistance training did not promote significant (p > 0.05) changes in MHC content of the TRCR group compared to the CO group. The data show that Cr supplementation provides a potential action to abolish the exercise-induced MHC isoform transitions from slow to fast in slow-twitch muscle. Thus, Cr supplementation might be a suitable strategy to maintaining a slow phenotype in slow muscle during resistance training, which may be favorable to maintenance of muscle oxidative capacity of endurance athletes.

Plasticidade muscular no exercício físico / Plasticity in muscular exercise

O objetivo deste estudo foi elaborar uma revisão dos principais mecanismos celulares e moleculares envolvidos no processo de hipertrofia e modulação fenotípica do músculo esquelético, em resposta ao exercício/treinamento físico. Inicialmente, apresentamos uma visão geral do músculo esquelético, com ênfase nas características gerais das fibras musculares e na plasticidade muscular. Em seguida, descrevemos a morfologia e a participação dos mionúcleos e das células satélites durante a hipertrofia muscular, e também, a atuação dos fatores de crescimento sobre a atividade das células satélites. Finalmente, apontamos as principais vias moleculares que mediam as alterações na expressão de proteínas músculo-específicas, de acordo com a especificidade das respostas funcionais ao exercício/treinamento físico.

The aim of this study was prepare a review of the majors cellular and molecular mechanisms involved in hypertrophy and phenotypic modulation of skeletal muscle in response to exercise/physical training. Initially, we present an overview of skeletal muscle, with emphasis on the general characteristics of the muscle fibers and muscle plasticity. Then, we describe the morphology and participation of myonuclei and satellite cells during muscle hypertrophy, and also the action of growth factors on the activity of cells satellites. Finally, we showed the key molecular pathways that mediate changes in the expression of muscle-specific proteins, according to the specificity of functional responses to the exercise/physical training.

Morphology and skeletal muscle growth in pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae) - DOI: 10.4025/actascibiolsci.v30i3.3640 / Morfologia e crescimento do músculo estriado esquelético no pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae) - DOI: 10.4025/actascibiolsci.v30i2.3640

The aim of this work was to evaluate the morphological and growth characteristics of skeletal muscle tissue in pirarucu (Arapaima gigas) using alevins (50 days old) and juveniles (1 year old). Muscle samples were collected from dorsal, lateral cranial, and lateral caudal regions, and then frozen in liquid nitrogen. Histological frozen sections (10 µm) were stained with HE and Gomori Trichrome for morphological analysis, and NADH-TR to evaluate muscle fiber oxidative metabolism. Morphometric analysis samples were obtained from dorsal and lateral cranial regions, and smallest diameter white fibers were measured. White dorsal muscle was thicker and two muscle fiber compartments were identified in the lateral cranial region: red (superficial) and white (deep) muscle. Hyperplasia muscle growth predominated in alevins and hypertrophy in juveniles.

O objetivo deste trabalho foi avaliar as características morfológicas e de crescimento do músculo estriado esquelético no pirarucu (Arapaima gigas). Foram utilizados animais em duas fases de crescimento: alevinos, com 50 dias de idade, e juvenis, com um ano de idade. Após eutanásia dos animais, fragmentos musculares das regiões dorsal, lateral cranial e lateral caudal foram coletados e congelados em nitrogênio líquido. Cortes histológicos (10 µm) foram submetidos às colorações HE e Tricrômico de Gomori, para a análise morfológica, e NADH-TR, para a análise do metabolismo oxidativo das fibras musculares. Foi calculado o menor diâmetro das fibras musculares brancas nas regiões dorsal e lateral cranial. A musculatura dorsal branca mostrou-se mais desenvolvida e, na musculatura lateral, observaram-se compartimentos distintos: superficial vermelho e profundo branco. Nos alevinos, o crescimento muscular ocorreu predominantemente por hiperplasia das fibras e, nos juvenis, predominou o crescimento muscular por hipertrofia.