Physical training reverses changes in hepatic mitochondrial diameter of Alloxan-induced diabetic rats.

OBJECTIVE: To investigate the effects of physical training on metabolic and morphological parameters of diabetic rats. METHODS: Wistar rats were randomized into four groups: sedentary control, trained control, sedentary diabetic and trained diabetic. Diabetes mellitus was induced by Alloxan (35mg/kg) administration for sedentary diabetic and Trained Diabetic Groups. The exercise protocol consisted of swimming with a load of 2.5% of body weight for 60 minutes per day (5 days per week) for the trained control and Trained Diabetic Groups, during 6 weeks. At the end of the experiment, the rats were sacrificed and blood was collected for determinations of serum glucose, insulin, albumin and total protein. Liver samples were extracted for measurements of glycogen, protein, DNA and mitochondrial diameter determination. RESULTS: The sedentary diabetic animals presented decreased body weight, blood insulin, and hepatic glycogen, as well as increased glycemia and mitochondrial diameter. The physical training protocol in diabetic animals was efficient to recovery body weight and liver glycogen, and to decrease the hepatic mitochondrial diameter. CONCLUSION: Physical training ameliorated hepatic metabolism and promoted important morphologic adaptations as mitochondrial diameter in liver of the diabetic rats.

Physical training prevent and treat hepatic lipid accumulation induced by fructose-rich diet / Treinamento físico previne e trata acumulação lipídica hepática induzida por dieta rica em frutose

This study aims to examine the effects of physical training performed in early (preventive) or late (therapeutic) protocols on body weight gain, glucose tolerance, and triglycerides accumulation in rats fed on a fructoserich diet. Wistar rats were allocated into two major groups according to the diet received: Control (C- standard diet) and Fructose (F- diet containing 60% fructose) fed during 120 days. Next, these two groups were distributed into six groups: C and F that were kept inactive; CTE (Control Trained Early) and FTE (Fructose Trained Early) that were submitted to Anaerobic Threshold (AnT) training from 28 to 120 days; CTL (Control Trained Late) and FTL (Fructose Trained Late) trained from 90 to 120 days. Physical Training was composed by swimming (5 days/week) at AnT determined by maximum lactate stead state (MLSS). The Oral Glucose Tolerance Test (oGTT) was performed 48h after the last in vivo analysis and did not showed differences between the groups. After, the animals were euthanized for heart, liver, and adipose tissue extraction. The early exercised animals had lower body weight compared to their sedentary littermates. Also, the fructose-rich diet increased liver lipids content in the sedentary animals and physical training successfully reduced this parameter in both major groups. These results suggests that physical training at the AnT performed in early or late protocols are effective to prevent and treat metabolic disorders related to fructose intake.

Este estudo tem como objetivo examinar os efeitos do treinamento físico realizado em protocolos precoce (preventivo) ou tardio (terapêutico) sobre o ganho de massa corporal, tolerância à glicose e acúmulo de triglicerídeos em ratos alimentados com dieta rica em frutose. Ratos Wistar foram alocados em dois grupos principais de acordo com a dieta recebida: Controle (C, dieta padrão) e Frutose (F, dieta contendo 60% de frutose) durante 120 dias. Em seguida, esses dois grupos foram distribuídos em seis grupos: C e F que foram mantidos inativos; CET (Controle Treinado Precoce) e FTE (Frutose Treinado Precoce) que foram submetidos ao treinamento no Limiar Anaeróbio (AnT) de 28 a 120 dias; CTL (controle treinado tardio) e FTL (frutose treinado tardio) treinados de 90 a 120 dias. O treinamento físico foi composto por natação (5 dias / semana) na AnT determinado pela Máxima Fase Estável de Lactato (MLSS). O Teste Oral de Tolerância à Glicose (oGTT) foi realizado 48 horas após a última análise in vivo e não mostrou diferenças entre os grupos. Depois, os animais foram eutanasiados para extração do coração, fígado e tecido adiposo. Os animais exercitados precocemente apresentaram menor massa corporal em comparação com os sedentários. Além disso, a dieta rica em frutose aumentou o conteúdo de lipídios do fígado nos animais sedentários e o treinamento físico reduziu com sucesso este parâmetro em ambos os grupos principais. Estes resultados sugerem que o treinamento físico no AnT realizado em protocolos precoce ou tardio são eficazes para prevenir e tratar distúrbios metabólicos relacionados à ingestão de frutose.

Impaired insulin signaling and spatial learning in middle-aged rats: The role of PTP1B.

The insulin and Brain-Derived Neurotrophic Factor (BDNF) signaling in the hippocampus promotes synaptic plasticity and memory formation. On the other hand, aging is related to the cognitive decline and is the main risk factor for Alzheimer's Disease (AD). The Protein-Tyrosine Phosphatase 1B (PTP1B) is related to several deleterious processes in neurons and emerges as a promising target for new therapies. In this context, our study aims to investigate the age-related changes in PTP1B content, insulin signaling, ß-amyloid content, and Tau phosphorylation in the hippocampus of middle-aged rats. Young (3 months) and middle-aged (17 months) Wistar rats were submitted to Morris-water maze (MWM) test, insulin tolerance test, and molecular analysis in the hippocampus. Aging resulted in increased body weight, and insulin resistance and decreases learning process in MWM. Interestingly, the middle-aged rats have higher levels of PTP-1B, lower phosphorylation of IRS-1, Akt, GSK3ß, mTOR, and TrkB. Also, the aging process increased Tau phosphorylation and ß-amyloid content in the hippocampus region. In summary, this study provides new evidence that aging-related PTP1B increasing, contributing to insulin resistance and the onset of the AD.

Physical training reverses changes in hepatic mitochondrial diameter of Alloxan-induced diabetic rats / Treinamento físico reverte alterações no diâmetro de mitocôndrias hepáticas de ratos diabéticos induzidos pela Aloxana

ABSTRACT Objective To investigate the effects of physical training on metabolic and morphological parameters of diabetic rats. Methods Wistar rats were randomized into four groups: sedentary control, trained control, sedentary diabetic and trained diabetic. Diabetes mellitus was induced by Alloxan (35mg/kg) administration for sedentary diabetic and Trained Diabetic Groups. The exercise protocol consisted of swimming with a load of 2.5% of body weight for 60 minutes per day (5 days per week) for the trained control and Trained Diabetic Groups, during 6 weeks. At the end of the experiment, the rats were sacrificed and blood was collected for determinations of serum glucose, insulin, albumin and total protein. Liver samples were extracted for measurements of glycogen, protein, DNA and mitochondrial diameter determination. Results The sedentary diabetic animals presented decreased body weight, blood insulin, and hepatic glycogen, as well as increased glycemia and mitochondrial diameter. The physical training protocol in diabetic animals was efficient to recovery body weight and liver glycogen, and to decrease the hepatic mitochondrial diameter. Conclusion Physical training ameliorated hepatic metabolism and promoted important morphologic adaptations as mitochondrial diameter in liver of the diabetic rats.

RESUMO Objetivo Investigar os efeitos do treinamento físico nos parâmetros morfológicos e metabólicos de ratos diabéticos. Métodos Ratos Wistar foram randomizados para quatro grupos: controle sedentário, controle treinado, diabético sedentário e diabético treinado. Diabetes mellitus foi induzido por administração de Aloxana (35mg/kg) nos Grupos Diabético Sedentário e diabético treinado. O protocolo de treinamento físico incluiu natação com carga de 2,5% do peso corporal, por 60 minutos por dia (5 dias por semana) para os Grupos Controle Treinado e diabético treinado, durante 6 semanas. Ao final do experimento, os ratos foram sacrificados, e o sangue foi coletado para determinação das concentrações séricas de glicose, insulina, albumina e proteínas totais. Amostras do fígado foram coletadas para determinação do glicogênio, proteínas, DNA e diâmetro mitocondrial. Resultados O Grupo Sedentário Diabético apresentou redução no peso corporal, insulinemia e glicogênio hepático, além de maior glicemia e diâmetro mitocondrial hepático. O protocolo de treinamento físico em animais diabéticos foi eficiente para restaurar o peso corporal e o glicogênio hepático, além de reduzir o diâmetro mitocondrial hepático. Conclusão O treinamento físico melhorou o metabolismo hepático e promoveu importantes adaptações morfológicas, como no diâmetro mitocondrial no fígado de animais diabéticos.

Cerebellar Insulin/IGF-1 signaling in diabetic rats: Effects of exercise training.

The Diabetes Mellitus (DM) is a chronic disease associated with loss of brain regions such as the cerebellum, increasing the risk of developing neurodegenerative diseases such as Parkinson's disease (PD). In the brain of diabetic and PD organisms the insulin/IGF-1 signaling is altered. Exercise training is an effective intervention for the prevention of neurodegerative diseases since it release neurotrophic factors and regulating insulin/IGF-1 signaling in the brain. This study aimed to evaluate the proteins involved in the insulin/IGF-1 pathway in the cerebellum of diabetic rats subjected to exercise training protocol. Wistar rats were distributed in four groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD) and trained diabetic (TD). Diabetes was induced by Alloxan (ALX) (32mg/kgb.w.). The training program consisted in swimming 5days/week, 1h/day, during 6 weeks, supporting an overload corresponding to 90% of the anaerobic threshold. At the end, cerebellum was extracted to determinate the protein expression of GSK-3ß, IRß and IGF-1R and the phosphorylation of ß-amyloid, Tau, ERK1+ERK2 by Western Blot analysis. All dependent variables were analyzed by one-way analysis of variance with significance level of 5%. Diabetes causes hyperglycemia in both diabetic groups; however, in TD, there was a reduction in hyperglycemia compared to SD. Diabetes increased Tau and ß-amyloid phosphorylation in both SD and TD groups. Furthermore, aerobic exercise increased ERK1+ERK2 expression in TC. The data showed that in cerebellum of diabetic rats induced by alloxan there are some proteins expression like Parkinson cerebellum increased, and the exercise training was not able to modulate the expression of these proteins.

Hippocampal insulin signaling and neuroprotection mediated by physical exercise in Alzheimer´s disease

Abstract Epidemiological studies indicate continuous increases in the prevalence of Alzheimer’s Disease (AD) in the next few decades. The key feature of this disease is hippocampal neurodegeneration. This structure has an important role in learning and memory. Intense research efforts have sought to elucidate neuroprotective mechanisms responsible for hippocampal integrity. Insulin signaling seems to be a very promising pathway for the prevention and treatment of AD. This hormone has been described as a powerful activator of neuronal survival. Recent research showed that reduced insulin sensitivity leads to low-grade inflammation, and both phenomena are closely related to AD genesis. Concomitantly, exercise has been shown to exert anti-inflammatory effects and to promote improvement in insulin signaling in the hippocampus, which supports neuronal survival and constitutes an interesting non-pharmacological alternative for the prevention and treatment of AD. This review examines recent advances in understanding the molecular mechanisms involved in hippocampal neuroprotection mediated by exercise.(AU)

Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance.

[Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event.

Efeitos da participação em programa de atividade física para pessoas com a doença de Alzheimer / Effects of physical activity program for people with Alzheimer's disease

O envelhecimento populacional tem causado aumento da prevalência de doenças senis como a Doença de Alzheimer (DA). As atividades físicas podem amenizar o processo degenerativo da DA. O presente estudo foi desenhado para investigar os efeitos da atividade física em pessoas com DA no formato de estudo de caso. Para isso, participaram deste estudo dois sujeitos do projeto de extensão Programa de atividade física para pessoas com DA (Unisalesiano-Lins) que consiste em atividades físicas, realizadas durante 1 hora, 3 vezes/semana. No exercício agudo foi investigada a frequência cardíaca e pressão arterial antes, durante e após a sessão. Previamente a entrada destes participantes no projeto e após 4 meses de participação foram realizadas as seguintes avaliações: massa corporal, estatura, minimental, flexibilidade e a escala de equilíbrio funcional (Berg). Com os atendimentos demonstrou-se aumento de 36% na frequência cardíaca e 15,2% na pressão arterial. Foram encontradas alterações que apontam para possível melhoria nas funções cognitivas (6,25%) e equilíbrio (3,1%). Com relação à flexibilidade, os pacientes apresentaram resultados opostos de aumento (37,1%) e diminuição (-3,6%). Pode ser concluído que a participação no programa apresentou resultados satisfatórios de melhora ou manutenção das funções em aspectos cognitivos e físicos. (AU)

With the population ageing, the prevalence of diseases related to age, like Alzheimer's disease (AD), are increasing. The physical activity can decrease the degenerative process of AD. The present study case was designed to investigate the effects of physical activity on patients with AD. Two subjects participated in a physical activity program for people with AD (UnisalesianoLins) consisting of physical activity during 1 hour, 3 times/week. Heart rate and blood pressure were measured before, during and after acute exercises. Prior to the beginning of this program and after 4 months of participation, the following evaluations were performed: weight, height, mini mental test, flexibility and Berg balance scale. During the sessions, we observed heart rate (36%) and blood pressure (15.2%) increase. It was found possible improvements in cognitive functions (6.25%) and balance (3.1%). As regard to flexibility, the patients showed opposite results: increase (37.1%) and decrease (3.6%). It can be concluded that physical activity promoted good results, improving or keeping the functions after the trial period in cognitive and physical aspects. (AU)

Effects of participation in physical training program for patient with parkinson's disease: a case report / Efeitos da participação em programa de atividade física para pessoas com doença de parkinson: um estudo de caso

The aim of this study was to investigate the effects of physical activity in people with Parkinson's disease PD (case study). To this, a subject (54 years) participant of the PARKVIDA project performed physical exercise training 3 days/week. The intensity of physical activity was mild-moderate monitored by frequencimeter and consisted of aerobic exercises, strength and specific (motor coordination and balance) adapted from Gobbi's protocol. Before and after the period of 8 months were applied the tests: quality of life (SF-36), balance (unipodal support test), body composition, cardio respiratory fitness (spirometry) and a part of AAHPERD battery: coordination, agility, strength and flexibility. The results showed changes in physical aspects such as agility, balance, flexibility and coordination, concomitant with improvement in cardiorespiratory fitness and quality of life (dimension "pain"). In conclusion, this study suggests that changes promoted by physical activity can contribute to improve cardio respiratory conditioning, reducing the perception of pain and physical and motor improvements in patient with PD.

O objetivo deste estudo foi investigar os efeitos da atividade física em pessoas com PD doença de Parkinson (estudo de caso). Para isso, um sujeito (54 anos) participante do projeto PARKVIDA realizou o treinamento de exercício físico 3 dias/semana. A atividade física foi realizada em intensidade leve a moderada tendo sido monitorada por cardiofreqüencímetro e consistiu em exercícios aeróbicos, de força e específicos (coordenação motora e equilíbrio) adaptados do protocolo de Gobbi. Antes e após o período de 8 meses foram aplicados os testes: qualidade de vida (SF-36), equilíbrio (teste de apoio unipodal), composição corporal, aptidão cardio respiratória (espirometria) e uma parte da bateria AAHPERD: coordenação, agilidade, força e flexibilidade. Os resultados mostraram alterações em aspectos físicos, tais como agilidade, equilíbrio, flexibilidade e coordenação, concomitante com a melhoria na aptidão cardiorrespiratória e qualidade de vida (medida "dor"). Em conclusão, este estudo sugere que as mudanças promovidas pela atividade física podem contribuir para melhorar o condicionamento cardiorrespiratório, reduz a percepção da dor e promove melhorias físicas e motoras em pacientes com DP.

Effects of enriched environment on maximal lactate steady state of wistar rats / Efeitos do ambiente enriquecido na máxima fase estável do lactato de ratos wistar

The enriched environment (EE) is a combination of stimulations inserted in the cage, such as tunnels, exercise wheel and color objects, increased cage size and the number of rats. Although the EE can be promoter of physical activity (PA), the literature lacks studies showing the effects of this accumulation of PA in the rats. In this way, the present study aims to investigate the effects of EE on maximal lactate steady state in rats. To this, adult Wistar rats were randomly distributed into control group (CG), kept in conventional cages, and EE group (EEG), kept in enriched cages. Before and after the experimental period (six weeks) the animals were submitted for the maximal lactate steady state (MLSS) test. In the last week, length and body mass was measured. At the end of the experimental period, after euthanasia, blood sample was collected for the analyses of glucose and heart was weighted. To statistical analyses, after the test of normality, the parametric results were analyzed by Student's t test and nonparametric through Mann-Whintey test. There were no differences in serum glucose, body length, body and heart mass. The groups presented similar MLSS at beginning of experiment, however, MLSS load was higher in EE than CG at end of experiment. In conclusion, PA performed in the enriched cage increased the aerobic capacity in comparing to the conventional cage, even in the absence of significant changes in length and body weight and blood glucose.

O ambiente enriquecido (EE) é uma combinação de estímulos inseridos na gaiola, tais como túneis, roda de exercício e objetos coloridos, além de aumento do tamanho da gaiola e do número de ratos. Embora o EE possa ser promotor de atividade física (PA), a literatura carece de estudos mostrando os efeitos dessa acumulação de PA em ratos mantidos no EE. Desta forma, o presente estudo tem como objetivo investigar os efeitos do EE sobre a máxima fase estável do lactato. Para isso, ratos Wistar adultos foram distribuídos aleatoriamente em grupo controle (CG), mantidos em gaiolas convencionais e grupo AE (EEG), mantidos em gaiolas enriquecidas. Antes e após o período experimental (seis semanas), os animais foram submetidos ao teste de máxima fase estável do lactato (MLSS). Na última semana, comprimento e massa corporal foram registradas. No final do período experimental, após a eutanásia, amostra de sangue foi coletada para análise de glicose e a massa do coração foi registrada. Para as análises estatísticas, após o teste de normalidade, os resultados paramétricos foram analisados pelo teste t de Student e não paramétrico através do teste de Mann-Whintey. Não houve diferença nos níveis de glicose no soro, comprimento corporal e massa cardíaca. Os grupos apresentaram MLSS semelhante no início do experimento, no entanto, no final do experimento, a carga da MLSS foi maior no EEG comparado ao GC. Em conclusão, PA realizada na gaiola enriquecido aumentou a capacidade aeróbia em comparação com o grupo mantido em gaiolas convencionais, mesmo na ausência de mudanças significativas na massa e comprimento corporal e da glicemia.

The effects of environmental enrichment on biochemical and metric parameters of aged rats / Efeitos do ambiente enriquecido em parametros bioquímicos e métricos de ratos idosos

The enriched environment (EE) is a promoter of physical activity, by its characteristics such as ample room for movement and exploration, presence of wheels, tunnels and toys. The maintenance of animals in enriched environment can bring a range of benefits, but the majority of the researches investigate cognitive parameters and changes related to the nervous system. The aim of this study was to examine the effects of the maintenance of aged rats in enriched cages on biochemical and metric parameters. Wistar rats were randomly distributed (n=6) into two groups during 6 weeks: control (C) in a conventional cage and enriched environment (EE). The body mass were recorded weekly and the body length at the end of the study. After euthanasia, blood was collected for analysis of glucose, triglycerides and the brain was collected for analysis of mass. The EE group had higher brain mass and lower gain of body weight compared to control group. The control group animals had normal values of blood glucose and triglyceride levels, and the maintenance in an EE did not promote changes in these parameters. Therefore, it can be concluded that the EE group increases brain mass and reduces the gain of body weight without changing the blood glucose and triglycerides in aged animals.

O ambiente enriquecido (AE) pode ser considerado como promotor de atividade física, pelas suas características como um amplo espaço para deslocamento e exploração, a presença de rodas de atividade, túneis e brinquedos. A manutenção de animais em ambiente enriquecido pode proporcionar uma série de benefícios, mas grande parte dos estudos tem focado a investigação de parâmetros cognitivas e alterações relacionadas ao sistema nervoso. O objetivo deste estudo foi examinar os efeitos da manutenção de ratos idosos em gaiolas enriquecidas sobre parâmetros bioquímicos e métricas. Ratos Wistar foram distribuídos aleatoriamente ( n = 6) em dois grupos durante 6 semanas: controle (C) mantido em gaiola convencional e ambiente enriquecido (AE) . A massa corporal foi registrada semanalmente e o comprimento corporal ao final do estudo. Após a eutanásia, amostras de sangue foram coletadas para análise de glicose e triglicérides e o encéfalo foi coletado para registro da massa. O grupo AE apresentou maior massa encefálica e menor ganho de peso corporal, em comparação ao grupo controle. Os animais do grupo controle apresentaram valores normais de glicose e triglicerídeos no sangue e a manutenção no AE não promoveu alterações nestes parâmetros. Portanto, pode ser concluído que a manutenção no AE aumenta a massa encefálica e reduz o ganho de peso corporal sem alterar a glicose e triglicerídeos no sangue de animais idosos.

Efeitos da ingestão de óleo de linhaça e treinamento físico sobre a massa óssea de ratos Wistar / Effects of flaxseed oil intake and exercise training on bone mass of wistar rats

O treinamento físico é reconhecido como fator importante para prevenção e tratamento de doenças ósseas, como osteoporose. O Ômega 3, presente em alimentos como óleo de linhaça, também pode contribuir para manutenção da saúde óssea. Todavia, poucos estudos investigaram possíveis efeitos sinérgicos de ambos. Objetivo: objetiva-se investigar os efeitos da administração do óleo de linhaça e do treinamento físico sobre a massa óssea de ratos wistar saudáveis. Método: os ratos foram distribuídos em quatro grupos: controle (C), linhaça (L), treinado (T) e linhaça treinado (LT). O treinamento físico consistiu de 30 min/dia, 5 dias/semana, durante 8 semanas, suportando sobrecarga equivalente à 2,5 por cento massa corporal. O óleo de linhaça foi administrado via orogástrica por gavagem (0,5 ml/kg) durante 8 semanas. Os animais tiveram massa corporal registrada no início e final do período experimental e ingestões hídrica e alimentar foram coletadas na última semana de experimento. Após período experimental, os animais foram eutanasiados e a tíbia foi coletada para registros de comprimento e massa. Resultados e Discussão: nos parâmetros peso corporal, ingestões hídrica e alimentar e comprimento ósseo, a administração de linhaça e treinamento físico não causaram efeitos que promovessem diferença significativa nos valores. Todavia, o grupo que recebeu óleo de linhaça e foi submetido ao treinamento físico apresentou massa óssea da tíbia maior que os demais grupos. Conclusão: desta forma, pode ser concluído que, em animais saudáveis, este volume de treinamento físico e administração de óleo de linhaça concomitantemente promoveram aumento na massa tibial, sem provocar alterações nos demais parâmetros estudados...

Physical training is an important factor for the prevention and treatment of bone diseases like osteoporosis. Omega 3 found in foods such as flaxseed oil can also contribute to maintaining bone health. However, few studies have investigated possible synergistic effects of both. Objective: it aimed to verify the effects of administration of flaxseed oil and physical training in bone mass from healthy rats. Method: Wister rats were divided into four groups: control (C), linseed (L), trained (T) and flaxseed trained (LT). Exercise training consisted of 30 min / day, 5 days / week during 8 weeks supporting a load corresponding to 2.5 percent of the body weight. The flaxseed oil was administered via orogastric gavage (0.5 ml / kg) for 8 weeks. The animals had body mass recorded at the beginning and end of the experimental period, and water and food intakes collected in the last week of the experiment. After the experimental period, the animals were sacrificed and the tibia is removed to length and weight records. Results and Discussion: to body weight, water intake, food intake and bone length, the administration of flaxseed and/or physical training did not cause significant differences between the groups studied. However, the group that received flaxseed oil and was subjected to physical training had greater tibial bone mass than the other groups. Conclusion: it is concluded that this volume of physical training and administration of flaxseed oil concomitantly caused an increase in tibial mass without causing changes in other studied parameters in heathy rats...

Spatial memory in sedentary and trained diabetic rats: molecular mechanisms.

Diabetes mellitus is a chronic disease that has been associated with memory loss, neurological disorders, and Alzheimer's disease. Some studies show the importance of physical exercise to prevent and minimize various neurological disorders. It is believed that the positive effects of exercise on brain functions are mediated by brain insulin and insulin-like growth factor-1 (IGF-1) signaling. In this study, we investigate the role of swimming exercise training on hippocampus proteins related to insulin/IGF-1 signaling pathway in Type 1 diabetic rats and its effects on spatial memory. Wistar rats were divided into four groups namely sedentary control, trained control, sedentary diabetic (SD), and trained diabetic (TD). Diabetes was induced by Alloxan (ALX) (32 mg/kg b.w.). The training program consisted in swimming 5 days/week, 1 h/day, per 6 weeks, supporting an overload corresponding to 90% of the anaerobic threshold. We employed ALX-induced diabetic rats to explore learning and memory abilities using Morris water maze test. At the end of the training period, the rats were sacrificed 48 h after their last exercise bout when blood samples were collected for serum glucose, insulin, and IGF-1 determinations. Hippocampus was extracted to determinate protein expression (IR, IGF-1R, and APP) and phosphorylation (AKT-1, AKT-2, Tau, and ß-amyloide proteins) by Western Blot analysis. All dependent variables were analyzed by two-way analysis of variance with significance level of 5%. Diabetes resulted in hyperglycemia and hypoinsulinemia in both SD and TD groups (P < 0.05); however, in the training-induced group, there was a reduction in blood glucose in TD. The average frequency in finding the platform decreased in SD rats; however, exercise training improved this parameter in TD rats. Aerobic exercise decreased Tau phosphorylation and APP expression, and increased some proteins related to insulin/IGF-1 pathway in hippocampus of diabetic rats. Thus, these molecular adaptations from exercise training might contribute to improved spatial learning and memory in diabetic organisms.

Efeito do treinamento físico sobre o perfil metabólico e ósseo de ratos recém-desmamados / Effect of physical training on metabolic and bone profile in weanling rats

INTRODUÇÃO: A prática de exercícios de intensidade moderada pode reduzir o risco de infecções e melhorar os aspectos metabólicos do indivíduo. OBJETIVO: Investigar os efeitos do treinamento físico aeróbio sobre os aspectos metabólicos, ósseo e sistema imunológico. MÉTODOS: Vinte ratos machos, recém-desmamados, foram distribuídos em dois grupos experimentais: grupo sedentário (GS) e grupo treinado (GT). O GT foi submetido a um protocolo de natação, durante seis semanas consecutivas. Ao final do período experimental, foi realizada a contagem total e diferencial de leucócitos e hematócrito. Após o sacrifício, foram analisados: glicose, proteínas totais, triglicérides, colesterol; amostras do fígado e músculo para a determinação dos teores de glicogênio; e tíbia para determinação do comprimento e área óssea. Os dados foram analisados pela análise de variância ANOVA one-way e o nível de significância estabelecido foi p<0,05. RESULTADOS: O hematócrito (%) analisado apresentou diferença significativa, com maior valor para o GT (54,63 ± 1,41) que para o GS (49,5 ± 1,65). A contagem total de leucócitos não apresentou diferença significativa, assim como também não houve diferença na contagem diferencial. O colesterol total apresentou relevante diminuição no GT (GT = 68,27 ± 13,71 mg/dL; GS = 94,44 ± 28,09); os níveis de proteínas totais também apresentaram importante redução (GT = 7,3 ± 0,40 g/dL; GS = 7,74 ± 0,36 g/dL); os níveis de glicose e triglicérides não apresentaram diferenças significativas. Já o comprimento ósseo apresentou diferença significativa, com o comprimento do tibial do GT (40 ± 0,14* mm) sendo menor que o GC (42,10 ± 0,12 mm). A área tibial demonstrou menor valor para o GT (1,53 ± 0,12 cm²) que para o GS (1,67 ± 0,18 cm²), entretanto, a diferença não foi estatisticamente significante. CONCLUSÃO: O treinamento físico aeróbio é capaz de produzir algumas modificações fisiológicas peculiares em ratos jovens.

INTRODUCTION: The practice of moderate-intensity exercise can reduce the risk of infections and improve metabolic aspects of the person. OBJECTIVE: To investigate the effects of aerobic physical training on endocrine and metabolic aspects, bone and immune system. METHODS: Twenty Wistar rats were divided in two groups: sedentary (GS) and trained group (TG). Training program consisted in swimming, 6 weeks, supporting a workload corresponding to 5% of body weight. At the end of the experiment, were performed counting total and differential leukocyte count and hematocrit. After training period, were analyzed glucose, total protein, triglycerides, cholesterol, liver and muscle samples for the determination of the levels of glycogen, and determination of the tibia length and bone area. All dependent variables were analyzed by one-way analysis of variance (ANOVA) and a significance level of P < 0.05 was used for all comparisons. RESULTS: Hematocrit (%) analyzed showed a significant difference, with higher values ​​for TG (54.63 ± 1.41) than for the GS (49.5 ± 1.65). The total leukocyte count was not significantly different, as there was no difference in the differential count. Total cholesterol showed significant decrease in GT (GT = 68.27 ± 13.71 mg/dL; GS = 94.44 ± 28.09), the total protein levels also showed significant reduction (GT = 7.3 ± 0,40 g/dL; GS = 7.74 ± 0.36 g/dL) glucose levels and triglyceride showed no significant differences.The bone length showed a significant difference (GT = 40±0.14 mm; CG = 42.10 ± 0.12mm). The tibial area showed the lowest value for the GT (1.53 ± 0.12cm²) than for the GS (1.67 ± 0.18cm²) however the difference was not statistically significant. CONCLUSION: It can be concluded that aerobic exercise training is able to produce some unique physiological changes in young rats. There is also the need to prescribe exercises that meet the particular maturational stage of development.

Influência do exercício agudo no metabolismo de ratos com hipertireoidismo / Influence of acute exercise on the metabolism of rats with hyperthyroidism

Diversas investigações são encontradas na literatura apresentando características de intolerância ao exercício em indivíduos com hipertireoidismo. Apesar do apontamento de alguns motivos que explicariam tal fenômeno, poucos analisam as influências do exercício físico agudo no metabolismo glicídico e protéico de animais com esta patologia. Diante deste contexto, o objetivo do presente estudo foi analisar a influência de uma sessão de exercício físico aeróbio no metabolismo glicídico e protéico de ratos hipertireoideanos. Para tal, foram utilizados 26 ratos que foram mantidos em biotério com alimentação, temperatura ambiente e ciclo claro/escuro controlados, distribuídos nos seguintes grupos: controle repouso (CR) e controle exercício agudo (CA); hipertireoidismo repouso (HR) e hipertireoidismo exercício agudo (HA). Os animais do grupo hipertireoidismo foram induzidos ao quadro patológico por meio da administração de levotiroxina sódica por um período de 10 dias. Foi registrado o peso corporal, ingestão hídrica e alimentar, além de analisadas algumas variáveis teciduais e séricas. Com auxílio da estatística paramétrica e não paramétrica foram encontradas alterações no peso corporal e em variáveis séricas e teciduais quando comparados os grupos. Foi encontrado maior peso corporal nos grupos controle em relação aos animais com hipertireoidismo. A albumina e as proteínas mostraram-se maiores nos animais controle. A glicose apresentou reduzida concentração no HR e elevada no CA. A concentração de glicogênio apresentou-se elevada no tecido muscular para HR e hepático para CR. A razão proteína/DNA não sofreu alterações no tecido muscular, enquanto apresentou algumas modulações significativas no tecido hepático. Diante das modulações séricas e teciduais encontradas, concluímos que o exercício físico agudo parece ser capaz de alterar a dinâmica metabólica glicídica e protéica, sérica e tecidual em ratos com hipertireoidismo.

Several investigations are found in the literature showing characteristics of exercise intolerance in patients with hyperthyroidism. Despite the appointment of some reasons that explain this phenomenon, few studies analyze the influences of acute physical exercise on glicidic and proteic metabolism in animals with this disease. In this context, the objective of this study was to analyze the influence of an acute bout of aerobic exercise on glicidic and proteic metabolism in rats with hyperthyroidism. For this purpose, were used 26 rats, kept in cages with food, temperature and light/dark cycle controlled, divided into the following groups: resting control (CR) and control acute exercise (CA); hyperthyroidism rest (HR) and hyperthyroidism acute exercise (HA). The animals of group hyperthyroidism were induced by the pathological status with the administration of levothyroxine for a 10 d period. It was recorded the body weight, food and water intake, and some tissues and serum variables were analyzed. Using parametric and non parametric statistical tools, changes were found in body weight, besides serum and tissue variables when comparing the groups. Was found higher body weight in the control groups when compared to hyperthyroidism groups. The albumin and protein were higher in control animals. Glucose concentration was reduced in HR and elevated in CA. The glycogen concentration was increased in muscle tissue and liver for HR in relation to CR. The protein content, DNA and ratio protein/DNA have not changed in muscle tissue, while some showed significant modulations in liver tissue. Given the modulations found in serum and tissue, we conclude that acute physical exercise seems to be able to change the dynamics of protein and carbohydrate metabolism, serum and tissue in rats with hyperthyroidism.

Exercise at anaerobic threshold intensity and insulin secretion by isolated pancreatic islets of rats.

To evaluate the effect of acute exercise and exercise training at the anaerobic threshold (AT) intensity on aerobic conditioning and insulin secretion by pancreatic islets, adult male Wistar rats were submitted to the lactate minimum test (LMT) for AT determination. Half of the animals were submitted to swimming exercise training (trained), 1 h/day, 5 days/week during 8 weeks, with an overload equivalent to the AT. The other half was kept sedentary (sedentary). At the end of the experimental period, the rats were submitted to an oral glucose tolerance test and to another LMT. Then, the animals were sacrificed at rest or immediately after 20 minutes of swimming exercise at the AT intensity for pancreatic islets isolation. At the end of the experiment mean workload (% bw) at AT was higher and blood lactate concentration (mmol/L) was lower in the trained than in the control group. Rats trained at the AT intensity showed no alteration in the areas under blood glucose and insulin during OGTT test. Islet insulin content of trained rats was higher than in the sedentary rats while islet glucose uptake did not differ among the groups. The static insulin secretion in response to the high glucose concentration (16.7 mM) of the sedentary group at rest was lower than the sedentary group submitted to the acute exercise and the inverse was observed in relation to the trained groups. Physical training at the AT intensity improved the aerobic condition and altered insulin secretory pattern by pancreatic islets.

Efeitos em curto prazo da aplicação de aloxana para indução de diabetes em ratos Wistar / Effects in short-term of alloxan application to diabetes induction in Wistar rats

O presente estudo teve como objetivo verificar a ação da aloxana em parâmetros metabólicos e do sistema imune 24 e 192 horas após sua aplicação em ratos Wistar. Para isso, oito ratos foram mantidos em jejum de 12 horas e receberam aloxana monoidratada, Sigma (32 mg/kg de peso corporal) via endovenosa. Foram registrados os valores de massa corporal, ingestão hídrica e alimentar e realizada a contagem de leucócitos totais previamente, 24 e 192 horas após a aplicação da aloxana. As análises de glicemia e trigliceridemia foram realizadas previamente e 192 horas após a aplicação da aloxana. Após 24 horas, a aplicação da aloxana causou aumento da ingestão hídrica e redução da massa corporal, ingestão alimentar e contagem de leucócitos. Na avaliação realizada 192 horas após a aplicação da aloxana houve recuperação da ingestão alimentar e contagem de leucócitos. Por outro lado, neste período houve aumento da glicemia e ingestão hídrica além de redução da massa corporal. Isso indica que parte dos sinais de diabetes causados pela aloxanamanifesta-se em curto prazo da administração da droga.

The present study aimed to verify action of alloxan in metabolic and immune parameters after 24 and 192 hours of the injection in Wistar rats. Thus, eight rats were fasted and received monohidrated alloxan Sigma (32 mg/kg body weight) via endovenous. Glycemia and trglyceridemia analyzes were performed before and 192 hours after alloxan application. After 24 hours, alloxan application increased water intake and decreased body mass, food intake and leucocytes counting. 192 hours after alloxan application, there was a recuperation in food intake and leucocytes counting. On the other hand, in this period there was an increase of glycemia and water intake and reduction of body mass. These results indicate that some of diabetic signs caused by alloxan occur in short-term after drug administration.

Effects of physical training on the immune system in diabetic rats.

AIMS: This study aims to investigate the influence of physical training on the immune system of diabetic rats. MATERIALS AND METHODS: Adult male Wistar rats were distributed into Sedentary Control (SC), Trained Control (TC), Sedentary Diabetic (SD) and Trained Diabetic (TD) groups were used. Diabetes was induced by alloxan (32 mg/bw-i.v.). Training protocol consisted of swimming, at 32 +/- 1 degrees C, one hour/day, five days/week, supporting an overload equivalent to 5% of the body weight, during four weeks. At the end of the experiment the rats were sacrificed by decapitation and blood samples were collected for glucose, insulin, albumin, hematocrit determinations, total and differential leukocyte counting. Additionally, liver samples for glycogen analyses were obtained. RESULTS: The results were analyzed by one way at a significance level of 5%. Diabetes reduced blood insulin, liver glycogen stores and increased blood glucose and neutrophil count. Physical training restored glycemia, liver glycogen levels, neutrophils and lymphocytes count in diabetic rats. CONCLUSIONS: In summary, physical training was able to improve metabolic and immunological aspects in the experimental diabetic rats.

Effects of exercise training on hippocampus concentrations of insulin and IGF-1 in diabetic rats.

The present study investigated the role of swimming training on cerebral metabolism and hippocampus concentrations of insulin and IGF-1 in diabetic rats. Wistar rats were divided in sedentary control (SC), trained control (TC), sedentary diabetic (SD), and trained diabetic (TD). Diabetes was induced by Alloxan (35 mg kg(-1) b.w.). Training program consisted in swimming 5 days/week, 1 h/day, 8 weeks, supporting a load corresponding to 90% of maximal lactate steady state (MLSS). For MLSS determination, rats were submitted to three sessions of 25-min supporting loads of 4, 5, or 6% of body wt, with intervals of 1 week. Blood samples were collected every 5 min for lactate determination. An acute exercise test (25 min to 90% of MLSS) was done in 7th week to confirm the efficacy of training. All dependent variables were analyzed by one-way analysis of variance (ANOVA) and a significance level of P < 0.05 was used for all comparisons. The Bonferroni test was used for post hoc comparisons. At the end of the training period, rats were sacrificed and sample blood was collected for determinations of serum glucose, insulin, GH, and IGF-1. Samples of gastrocnemius muscle and liver were removed to evaluate glycogen content. Hippocampus was extracted to determinate glycogen, insulin, and IGF-1 contents. Diabetes decreased serum GH, IGF-1, and liver glycogen stores in SD. Diabetes also increased hippocampus glycogen and reduced hippocampus IGF-1 content. Physical training recovered liver and hippocampus glycogen stores and promoted increases in serum IGF-1 in TD group. Physical training restored hippocampus IGF-1 content in diabetic group. It was concluded that in diabetic rats, physical training induces important metabolic and hormonal alterations that are associated with an improvement in glucose homeostasis and with an increased activity in the systemic and hippocampus IGF-1 peptide.

Effects of physical training on serum and pituitary growth hormone contents in diabetic rats.

The present study investigated the effects of moderate physical training on some of the parameters in the GH-IGF axis in experimental diabetic rats. Male Wistar rats were allocated into the following groups: sedentary control, trained control, sedentary diabetic, trained diabetic. Diabetes was induced by alloxan (32 mg/kg, b.w. iv). The physical training protocol consisted of 1 h swimming session/day, 5 days/week for 8 weeks supporting a load corresponding to 90% of maximal lactate steady state. After the experimental period, blood was collected to measure serum glucose, insulin, triglycerides, albumin, insulin-like growth factors-I (IGF-I), and growth hormone (GH). Pituitary gland was removed for GH quantification. Diabetes increased blood glucose and triglycerides and decreased insulin, IGF-I, serum and pituitary GH. Physical training decreased glucose and triglycerides, and also counteracted the reduction of serum IGF-I in diabetic rats. In conclusion, physical training recovered serum IGF-I showing no alteration of serum or pituitary GH levels.