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.

Effects of swimming training on tissue glycogen content in experimental thyrotoxic rats.

Thyrotoxicosis, a condition in which there is an excessive amount of circulating thyroid hormones, leads to reduced glycogen content in different tissues. In this study we analyzed the effects of aerobic swimming training on liver, heart, and skeletal muscle glycogen content in experimentally induced thyrotoxicosis. Wistar male rats were divided into euthyroid sedentary (ES, n = 12), euthyroid trained (ET, n = 11), thyrotoxic sedentary (TS, n = 12), and thyrotoxic trained (TT, n = 10) groups. Thyrotoxic groups received daily i.p. doses of T4 (sodium levothyroxine, 25 µg/100 g body mass) through the experimental period, and trained groups swam for 1 h at 80% of the aerobic-anaerobic transition intensity, 5 days/week for 4 weeks. Heart and liver glycogen stores were ∼30% lower in T4 treated compared with nontreated groups, but were not changed by training status. On the other hand, glycogen content in mixed fiber type gastrocnemius of TT was 1.5- to 2.3-fold greater than those in other groups, whereas no significant differences were found for the slow soleus muscle. Increased gastrocnemius but not soleus, liver, or heart glycogen indicates that in mild long-term thyrotoxicosis chronic swimming affects glycogen stores in a tissue-specific manner.

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.

Growth factors and glucose homeostasis in diabetic rats: effects of exercise training.

To investigate the alterations of glucose homeostasis and variables of the insulin-like growth factor-1 (IGF-1) growth system in sedentary and trained diabetic (TD) rats, Wistar rats were divided into sedentary control (SC), trained control (TC), sedentary diabetic (SD), and TD groups. Diabetes was induced by Alloxan (35 mg kg(-1) b.w.). Training program consisted of swimming 5 days week(-1), 1 h day(-1), during 8 weeks. Rats were sacrificed and blood was collected for determinations of serum glucose, insulin, growth hormone (GH), IGF-1, and IGF binding protein-3 (IGFBP-3). Muscle and liver were removed to evaluate glycogen content. Cerebellum was extracted to determinate IGF-1 content. Diabetes decreased serum GH, IGF-1, IGFBP-3, liver glycogen, and cerebellum IGF-1 peptide content in baseline condition. Physical training recovered liver glycogen and increased serum and cerebellum IGF-1 peptide in diabetic rats. Physical training induces important metabolic and hormonal alterations that are associated with an improvement in glucose homeostasis and serum and cerebellum IGF-1 concentrations.

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats.

BACKGROUND: Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan. METHODS: Female Wistar rats aged 6 days were injected with either 250 mg/kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index. RESULTS: The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls. CONCLUSION: Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition.

Influence of ultrasound and physical activity on bone healing.

The aim of this study was to investigate the effects of ultrasound treatment of experimental bone fractures and the effects of physical exercise on the speed of bone consolidation. Osteotomy was performed on the upper third of the right tibia of rats. Physical training consisted of swimming 1 h per d with a load of 5% body weight and therapy with medium-intensity ultrasound was applied for 5 min daily. Young adult male Wistar rats were divided into four groups: (1) osteotomized sedentary animals with no ultrasound treatment (OSnUS); (2) trained with no ultrasound treatment (OTnUS); (3) sedentary with ultrasound treatment (OSwUS); and (4) trained with ultrasound treatment (OTwUS). The animals were sacrificed for the following analyses: muscle glycogen and serum alkaline phosphatase on the 5th, 10th, 20th and 30th days and histological slices of the bone on the 5th and 20th days. The results show that ultrasound is better in the initial phases of the process of bone tissue repair and physical exercise at the end of bone consolidation. These facts suggest that the treatments herein used prove favorable to the bone regenerative process, as the overall ossification process has been accelerated.

Moderate physical training increases brain insulin concentrations in experimental diabetic rats.

Insulin is an important modulator of growth and metabolic function in the central nervous system. The aim of this study was to investigate the influence of swimming physical training (at 32 degrees +/- 1 degree C, 1 hr/day, 5 days/week, with an overload equivalent to 5% of the body weight, for 4 weeks) on brain insulin concentrations in alloxan induced type 1 diabetic rats. Training attenuated hyperglycemia but had no effect on insulinemia in diabetic rats. Hematocrit and blood albumin values remained without changes. Brain insulin did not change in diabetic rats. However, physical training increased the concentration in both control and diabetic rats. It is concluded that in the present experimental conditions, diabetes had no influence on brain insulin, however moderate physical training increased the hormone in both control and diabetic animals.

Effects of swimming training at the intensity equivalent to aerobic/anaerobic metabolic transition in alloxan diabetic rats.

The present study was designed to determine the exercise intensity equivalent to the metabolic aerobic/anaerobic transition of alloxan diabetic rats, through lactate minimum test (LMT), and to evaluate the effects of swimming exercise at this intensity (LM) on the glucose and protein metabolism of these animals. Adult male Wistar rats received alloxan (SD, alloxan-injected rats that remained sedentary) intravenously (30 mg kg(-1) body weight) for diabetes induction. As controls (SC, vehicle-injected rats that remained sedentary), vehicle-injected rats were utilized. Two weeks later, the animals were submitted to oral glucose tolerance test (oGTT) and LMT. After the tests, some of the animals were submitted to swimming exercise training [TC (vehicle-injected rats that performed a 6-week exercise program) and TD (alloxan-injected rats that performed a 6-week exercise program)] for 1 h day(-1), 5 days week(-1), with an overload equivalent to LM determined by LMT, for 6 weeks. At the end of the experiment, the animals were submitted to a second LMT and oGTT, and blood and skeletal muscle assessments (protein synthesis and degradation in the isolated soleus muscle) were made. The overload equivalent to LM at the beginning of the experiment was lower in the SD group than in the SC group. After training, the overload equivalent to LM was higher in the TC and TD groups than in the SC and SD groups. The blood glucose of TD rats during oGTT was lower than that of SD rats. Protein degradation was higher in the SD group than in other groups. We conclude that LMT was sensitive to metabolic and physiologic alterations caused by uncontrolled diabetes. Training at LM intensity improved aerobic condition and the glucose and protein metabolism of alloxan diabetic rats.

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.

Effect on physical fitness of a 10-year physical activity intervention in primary health care settings.

BACKGROUND: Interventions in primary health care settings have been effective in increasing physical fitness. In 2001, the Programa de Exercício Físico em Unidades de Saúde (Physical Exercise in Health Primary Care Program-PEHPCP) was launched in Rio Claro City, Brazil. The intervention consisted of biweekly, 60-minute group sessions in all primary health care settings in the city. This study evaluated the effect of PEHPCP on physical fitness and on the aging process after a decade of ongoing implementation. METHODS: There were 409 women (50 ± 26 y old) and 31 men (64 ± 10 y old) who were eligible for this study. Every 4 months, participants completed the American Alliance for Health, Physical Education, Recreation and Dance standardized tests. RESULTS: Program participation was associated with a reduced effect, compared with baseline, of the natural decline of physical fitness caused by aging, as represented by changes in the following measures: coordination test time, -0.44 seconds; agility and dynamic balance test time; -1.81 seconds; aerobic capacity test time, 3.57 seconds; and muscle strength exercises, +0.60 repetitions. No significant effect on flexibility was found. CONCLUSIONS: The PEHPCP showed potential in improving muscle strength, coordination, aerobic capacity, and agility and dynamic balance in participants and in maintaining flexibility in participants.

Endurance training improves responsiveness to insulin and modulates insulin signal transduction through the phosphatidylinositol 3-kinase/Akt-1 pathway.

BACKGROUND: Endurance training increases insulin-stimulated muscle glucose transport and leads to improved metabolic control in diabetic patients. OBJECTIVE: To analyze the effects of endurance training on the early steps of insulin action in muscle of rats. DESIGN: Male rats submitted to daily swimming for 6 weeks were compared with sedentary controls. At the end of the training period, anesthetized animals received an intravenous (i.v.) injection of insulin and had a fragment of their gastrocnemius muscle excised for the experiments. METHODS: Associations between insulin receptor, insulin receptor substrates (IRS)-1 and -2 and phosphatidylinositol 3-kinase (PI3-kinase) were analyzed by immunoprecipitation and immunoblotting. Akt-1 serine phosphorylation and specific protein quantification were detected by immunoblotting of total extracts, and IRS-1/IRS-2-associated PI3-kinase activity were determined by thin-layer chromatography. RESULTS: Insulin-induced phosphorylation of IRS-1 and IRS-2 increased respectively by 1.8-fold (P<0.05) and 1.5-fold (P<0.05), whereas their association with PI3-kinase increased by 2.3-fold (P<0.05) and 1.9-fold (P<0.05) in trained rats as compared with sedentary controls, respectively. The activity of PI3-kinase associated with IRS-1 and IRS-2 increased by 1.8-fold (P<0.05) and 1.7-fold (P<0.05) respectively, in trained rats as compared with their untrained counterparts. Serine phosphorylation of Akt-1/PKB increased 1.7-fold (P<0.05) in trained rats in response to insulin. These findings were accompanied by increased responsiveness to insulin as demonstrated by a reduced area under the curve for insulin during an i.v. glucose tolerance test, by increased glucose disappearance rate during an insulin tolerance test, and by increased expression of glucose transporter-4. CONCLUSIONS: The increased responsiveness to insulin induced by chronic exercise in rat skeletal muscle may result, at least in part, from the modulation of the insulin signaling pathway at different molecular levels.

Insulin concentrations in cerebellum and body balance in diabetic male rats: aerobic training effects.

UNLABELLED: Brain insulin has had widespread metabolic, neurotrophic, and neuromodulatory functions and has been involved in the central regulation of food intake and body weight, learning and memory, neuronal development, and neuronal apoptosis. PURPOSE: The present study investigated the role of swimming training on cerebral metabolism on insulin concentrations in cerebellum and the body balance performance of diabetic rats. METHODS: Forty Male Wistar rats were divided in four groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD), and trained diabetic (TD). Diabetes was induced by alloxan (32mgkg b.w.), single dose injection. The mean blood glucose of diabetic groups was 367±40mg/dl. Training program consisted in swimming 5days/week, 1h/day, 8weeks, supporting a workload corresponding to 90% of maximal lactate steady state (MLSS). For the body balance testing rats were trained to traverse for 5min daily for 5-7days. 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: The body balance testing scores were different between groups. Insulin concentrations in cerebellum were not different between groups. CONCLUSION: It was concluded that in diabetic rats, aerobic training does not induce alterations on cerebellum insulin but induces important metabolic, hormonal and behavioral alterations which are associated with an improvement in glucose homeostasis, serum insulin concentrations and body balance.

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.

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.

Acute exercise reverses aged-induced impairments in insulin signaling in rodent skeletal muscle.

The insulin resistance associated with aging is improved by exercise, but the molecular mechanisms of this improvement are not fully understood. We investigated whether the improvement in insulin action, associated with acute exercise in old rats is dependent on the modulation of pIRS-1Ser307, JNK, IkBalpha and PTP-1B. Aging rats were subjected to swimming for two 1.5-h long bouts, separated by a 45min rest period. Sixteen hours after the exercise, the rats were killed and proteins from the insulin signaling pathway were analyzed by immunoblotting. Our results show that the reduction in glucose disappearance rate (Kitt), observed in aged rats, was restored at 16h after exercise. Aging led to an increase in Ser307 phosphorylation of IRS-1, and this was reversed by exercise in the skeletal muscle, in parallel with a reduction in pJNK and IkBalpha degradation. Moreover, aging induced an increase in the expression of PTP-1B and attenuated insulin signaling in the muscle of rats, a phenomenon that was reversed by exercise. Interestingly, the decrease in PTP-1B expression in the muscle of exercised old rats was accompanied by an increase in SIRT1 expression. These results provide new insights into the mechanisms by which exercise restores insulin sensitivity during aging.

Effect of swimming training on stress-related metabolic parameters of diabetic and non-diabetic rats / Efeito do treinamento de natação sobre estresse metabólico de ratos diabéticos e não diabéticos

Physical training can be an useful strategy to attenuate the stress markers concentrations and hyperglycemia on type 1 diabetic rats. Thus, the purpose of the present study was to investigate the effects of swimming training on metabolic parameters and stress markers in diabetic and non-diabetic rats. Twenty-four adult male Wistar rats were recruited. The rats were randomly divided into four groups, sedentary control (SC), trained control (TC), sedentary diabetic (SD), and trained diabetic (TD). The diabetic rats received alloxan monohydrate and the trained rats swam for 60 minutes five times per week. The training load was 3.5% and 5% of body weight to diabetic and non-diabetic rats, respectively. After the euthanasia, blood samples for determination of corticosterone, insulin, and glucose levels were collected, and the adrenal weight, adrenal cholesterol concentration, gastrocnemius glycogen concentration, and muscle total protein content were also determined. To compare the groups, a variance analysis was used with Tukey´s post-hoc. The significance level of 5% was adopted. The adrenal weight was higher in SD (17.2±0.6g) than the other groups (SC: 12.2±0.8g; TC: 13.7±0.6g; TD: 14.3±0.8g), and TD had similar values of TC. The corticosterone level of SD was higher than SC and TC. The serum glucose was higher in the diabetic groups and insulin was lower in these groups. Six weeks of swimming training was efficient to reduce stress markers concentration in type 1 rats. Training may be a good tool to avoid the reduction on muscle protein content in type 1 diabetic rats.

Treinamento físico pode ser uma estratégia útil para atenuar as concentrações de marcadores de estresse e hiperglicemia em ratos diabéticos tipo 1. Assim, objetivo do estudo foi investigar o efeito do treinamento de natação sobre os parâmetros metabólicos e marcadores de estresse em ratos diabéticos e não diabéticos. Foram selecionados vinte e quatro ratos machos Wistar divididos em quatro grupos, controle sedentário (SC), controle treinado (TC), diabético sedentário (SD) e diabético treinado (TD). A indução de diabetes foi por aloxana monoidratada. Os ratos foram submetidos a 60 minutos de natação cinco vezes por semana com carga de 3,5% e 5% do peso corporal para ratos diabéticos e não diabéticos, respectivamente. Depois da eutanásia, foram determinados corticosterona, insulina, glicose, peso da adrenal, concentração de colesterol da adrenal e glicogênio do músculo gastrocnêmio e conteúdo proteico total muscular também foram determinados. Foi aplicada análise de variância e Post Hoc de Tukey, com significância estatística menor que 5%. Peso da adrenal foi maior em SD (17.2±0.6g) que nos outros grupos (SC: 12.2 ±0.8g; TC: 13.7±0.6g; TD: 14.3±0.8g) e TD apresentou valores similares de TC. A corticosterona de SD foi maior do que SC e TC. Glicose sérica foi elevada no grupo diabético e a insulina foi menor neste grupo. Seis semanas de treinamento de natação foram eficientes para reduzir a concentração de marcadores de estresse em ratos diabéticos tipo 1. O treinamento de natação pode ser uma ferramenta útil para evitar a redução do conteúdo proteico muscular em ratos diabéticos tipo 1.

Exercise test and glucose homeostasis in rats treated with alloxan during the neonatal period or fed a high calorie diet.

BACKGROUND: Animal models appear well-suited for studies into the role of exercise in the prevention of non-insulin-dependent diabetes mellitus (NIDDM). The aim of the present study was to analyze glucose homeostasis and blood lactate during an exercise swimming test in rats treated with alloxan during the neonatal period and/or fed a high calorie diet from weaning onwards. METHODS: Rats were injected with alloxan (200 mg/kg, i.p.) or vehicle (citrate buffer) at 6 days of age. After weaning, rats were divided into four groups and fed either a balanced diet or a high-caloric diet as follows: C, control group (vehicle + normal diet); A, alloxan-treated rats fed the normal diet; H, vehicle-treated rats fed the high-caloric diet; and HA, alloxan-treated rats fed the high-caloric diet. RESULTS: Fasting serum glucose levels were higher in groups A and AH compared with the control group. The Homeostatic Model Assessment index varied in the groups as follows: H>A>HA = C. There were no differences in free fatty acids or blood lactate concentrations during the swim test. CONCLUSIONS: Alloxan-treated rats fed a normal or high-caloric diet have the potential to be used in studies analyzing the role physical exercise plays in the prevention of NIDDM.

Efeitos do exercicio agudo sobre biomarcadores sericos de ratos diabeticos / The effects of acute exercise on serum biomarkers in diabetics rats / Efectos del ejercicio agudo sobre biomarcadores de suero em ratones diabeticos

INTRODUÇÃO: As respostas ao exercício agudo dos biomarcadores, como a fosfatase alcalina (FA) e a creatina quinase (CK) séricas têm sido pouco investigadas em ratos diabéticos. OBJETIVOS: Verificar os efeitos do exercício físico aeróbio agudo sobre as concentrações de CK e FA, bem como, avaliar o estado hídrico em ratos diabéticos experimentais. MATERIAIS E MÉTODOS Foram utilizados ratos Wistar machos, adultos jovens, distribuídos em dois grupos: diabéticos (DA) e controles (CA). O diabetes foi induzido por meio da administração de aloxana monoidratado Sigma(r) (32 mg/kg de peso corporal). Duas semanas após confirmação do diabetes, ambos os grupos foram submetidos a uma sessão aguda de natação por 30 min, com carga aeróbia (4,5 % do peso corporal). Foram avaliados: glicose, hematócrito, CK, FA, albumina e a cinética de lactato durante o exercício por meio de coletas 25 µL de sangue da cauda dos animais, nos minutos 0, 10, 20 e 30 de exercício. RESULTADOS: ANOVA de dois fatores para medidas repetidas e o teste post hoc de Tukey apontaram diminuição significativa dos valores de glicemia após o exercício para o grupo DA, aumento significativo de CK pós-exercício para o grupo DA, aumento significativo de hematócrito para ambos os grupos após exercício e manutenção da FA após exercício para o grupo DA. CONCLUSÃO: O exercício agudo aeróbio foi eficiente no controle dos níveis glicêmicos de ratos diabéticos. Entretanto, deve ser aplicado com cautela, pois induziu altos valores de CK, sugerindo possíveis lesões teciduais. .

INTRODUCTION: The responses to acute exercise on biomarkers, such as alkaline phosphatase (ALP) and creatine kinase (CK) serum levels have been little investigated in diabetic rats. OBJECTIVES: To investigate the effects of acute aerobic exercise on the concentrations of CK and ALP as well as evaluating the hydration status in diabetic rats. MATERIALS AND METHODS: Were used male Wistar rats, young adults, divided into two groups: diabetic (DA) and controls (CA). The diabetes was induced in the rats by administration of alloxan monohydrate Sigma(r) (32 mg/kg body weight). Two weeks after confirmation of diabetes, both groups were subjected to an acute swim session for 30 min, with aerobic load (4.5% body weight). Glucose, hematocrit, CK, ALP, albumin and lactate kinetics during exercise were evaluated by collecting 25µL of blood from the tail of the animals in minutes 0, 10, 20 and 30 of exercise. RESULTS: Two-way ANOVA for repeated measures and post hoc Tukey test showed significant decrease of glycemia after exercise for the DA group, significant increase in CK after exercise for the DA group, significant increase in hematocrit for both groups after exercise and maintenance of ALP after exercise for the DA group. CONCLUSION: The acute aerobic exercise was effective in controlling glucose levels in diabetic rats. However, it should be applied with caution, because it induced high CK values, suggesting possible tissue damage. .

INTRODUCCIÓN: Las respuestas al ejercicio agudo de los biomarcadores, como la fosfatasa alcalina (FA) y la creatina quinasa (CK) séricas han sido poco investigadas en ratones diabéticos. OBJETIVOS: Verificar los efectos del ejercicio físico aeróbico agudo sobre las concentraciones de CK y FA, bien como evaluar el estado hídrico en ratones diabéticos experimentales. MATERIALES Y MÉTODOS: Fueron utilizados ratones Wistar machos, adultos jóvenes, distribuidos en dos grupos: diabéticos (DA) y controles (CA). La diabetes fue inducida por medio de la administración de aloxana monohidratado Sigma(r) (32 mg/kg de peso corporal). Dos semanas después de la confirmación de la diabetes, ambos grupos fueron sometidos a una sesión aguda de natación por 30 minutos, con carga aeróbica (4,5% del peso corporal). Fueron evaluados: Glucosa, hematocrito, CK, FA, albumina y La cinética de lactato durante el ejercicio por medio de colectas de 25 µL de sangre de la cola de los animales, en los minutos 0, 10, 20 y 30 de ejercicio. RESULTADOS: ANOVA de dos factores para medidas repetidas y el test post hoc de Tukey apuntaron disminución significativa de los valores de glicemia después del ejercicio para el grupo DA, aumento significativo de CK después del ejercicio para el grupo DA, aumento significativo de hematocrito para ambos grupos después del ejercicio y mantenimiento de la FA después del ejercicio para el grupo DA. CONCLUSIÓN: El ejercicio agudo aeróbico fue eficiente en el control de los niveles glicémicos de ratones diabéticos. Entretanto, debe ser aplicado con cautela, pues indujo altos valores de CK, sugiriendo posibles lesiones tisulares. .

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.