Caffeine and Ovariectomy Debilitate Bone Health in Rats on Calcium-deficient Diet.

This study investigated the effects of ovariectomy and caffeine intake on bone health in rats on calcium-deficient diet. Forty adults female Wistar rats were divided into 4 groups in a 2x2 factorial design: Ovary (OVX/SHAM) and Caffeine (placebo/caffeine). The animals were housed in individual cages for 8 weeks, receiving 18-20g of AIN-93M diet per day, containing 50% of the daily recommended intake of calcium. The rats underwent ovariectomy (OVX) or laparotomy (SHAM) surgery. Caffeine groups received 6mg of caffeine/kg/day. After euthanasia, the tibia and femur were dissected to determine the calcium content and bone fracture strength, respectively. Blood sample was collected to determine serum Ostase. 24-hour urine was analyzed for excreted calcium and NTx. Reduced bone fracture strength and calcium content were observed in OVX and Caffeine groups. When observed separately, OVX group showed increased urinary NTx and lower bone weight, blood ostase, and urinary calcium. Caffeine groups showed elevated urinary calcium. There was a positive correlation between bone fracture strength and calcium content. NTx correlated negatively with bone calcium, fracture strength and thickness. In conclusion, both OVX and caffeine intake debilitate bone health in rats on calcium-deficient diet.

Validity and reproducibility of the CALERA Research Sensor to estimate core temperature at different intensities of a cycling exercise in the heat.

Recent heatwaves have highlighted the importance of accurate and continuous core temperature (TCORE) monitoring in sports settings. For example, accentuated rises in TCORE caused by physical exercises under environmental heat stress increase the risk of heat illnesses. Thus, using valid and reproducible devices is essential to ensure safe sports practice. In this study, we assessed the validity and reproducibility of the Calera Research Sensor (CRS) in estimating the TCORE of male and female participants during cycling exercise in a hot environment. Seven male (age: 36.2 ± 10.1 years) and eight female cyclists (age: 30.1 ± 5.0 years) underwent two identical cycling trials in a dry-bulb temperature of 32 °C and relative humidity of 60%. The protocol consisted of an initial 10-min rest followed by a 60-min exercise comprising 10 min at 20%, 25 min at 55%, and 25 min at 75% of maximal aerobic power, and an additional 25 min of post-exercise recovery. TCORE was recorded simultaneously every minute using a gastrointestinal capsule (TGi) and the CRS (TSENSOR). Bland-Altman analysis was performed to calculate bias, upper (LCS) and lower (LCI) concordance limits, and the 95% confidence interval (95%CI). The maximum acceptable difference between the two devices was predetermined at ±0.4 °C. A mixed linear model was used to assess the paired differences between the two measurement systems, considering the participants, trials, and environmental conditions as random effects and the cycling stages as fixed effects. An intra-class correlation coefficient (ICC) of 0.98 was recorded when analyzing data from the entire experiment. A non-significant bias value of 0.01 °C, LCS of 0.38 °C, LCI of -0.35 °C, and CI95% of ±0.36 °C were found. When analyzing data according to the participants' sex, CRS reproducibility was high in both sexes: ICC values of 0.98 and 0.99 were reported for males and females, respectively. CI95% was 0.35 °C in experiments with males and 0.37 °C with females, thereby falling within the acceptable margin of difference. Therefore, CRS was considered valid (compared to TGi) and reproducible in estimating TCORE in both sexes at various intensities of cycling exercise in the heat.

Resistance Exercise Training Mitigates Cardiac Remodeling Induced by a High-Fat Diet in Rodents: A Systematic Review. / O Treinamento Resistido Atenua a Remodelação Cardíaca Induzida por uma Dieta Hiperlipídica em Roedores: Uma Revisão Sistemática.

BACKGROUND: Obesity is associated with the development of cardiovascular diseases and is a serious public health problem. In animal models, high-fat diet (HFD) feeding impairs cardiac structure and function and promotes oxidative stress and apoptosis. Resistance exercise training (RT), however, has been recommended as coadjutant in the treatment of cardiometabolic diseases, including obesity, because it increases energy expenditure and stimulates lipolysis. OBJECTIVE: In this systematic review, we aimed to assess the benefits of RT on the heart of rats and mice fed HFD. METHODS: Original studies were identified by searching PubMed, Scopus, and Embase databases from December 2007 to December 2022. This study was conducted in accordance with the criteria established by PRISMA and registered in PROSPERO (CRD42022369217). The risk of bias and methodological quality was evaluated by SYRCLE and CAMARADES, respectively. Eligible studies included original articles published in English that evaluated cardiac outcomes in rodents submitted to over 4 weeks of RT and controlled by a sedentary, HFD-fed control group (n = 5). RESULTS: The results showed that RT mitigates cardiac oxidative stress, inflammation, and endoplasmic reticulum stress. It also modifies the activity of structural remodeling markers, although it does not alter biometric parameters, histomorphometric parameters, or the contractile function of cardiomyocytes. CONCLUSION: Our results indicate that RT partially counteracts the HFD-induced adverse cardiac remodeling by increasing the activity of structural remodeling markers; elevating mitochondrial biogenesis; reducing oxidative stress, inflammatory markers, and endoplasmic reticulum stress; and improving hemodynamic, anthropometric, and metabolic parameters.

FUNDAMENTO: A obesidade está associada ao desenvolvimento de doenças cardiovasculares e constitui um grave problema de saúde pública. Em modelos animais, a alimentação com uma dieta hiperlipídica (DH) compromete a estrutura e a função cardíaca e promove estresse oxidativo e apoptose. O treinamento resistido (TR), entretanto, tem sido recomendado como coadjuvante no tratamento de doenças cardiometabólicas, incluindo a obesidade, porque aumenta o gasto energético e estimula a lipólise. OBJETIVO: Na presente revisão sistemática, nosso objetivo foi avaliar os benefícios do TR no coração de ratos e camundongos alimentados com DH. MÉTODOS: Foram identificados estudos originais por meio de busca nas bases de dados PubMed, Scopus e Embase de dezembro de 2007 a dezembro de 2022. O presente estudo foi conduzido de acordo com os critérios estabelecidos pelo PRISMA e registrado no PROSPERO (CRD42022369217). O risco de viés e a qualidade metodológica foram avaliados pelo SYRCLE e CAMARADES, respectivamente. Os estudos elegíveis incluíram artigos originais publicados em inglês que avaliaram desfechos cardíacos em roedores submetidos a mais de 4 semanas de TR e controlados por um grupo controle sedentário alimentado com DH (n = 5). RESULTADOS: Os resultados mostraram que o TR atenua o estresse oxidativo cardíaco, a inflamação e o estresse do retículo endoplasmático. Também modifica a atividade de marcadores de remodelamento estrutural, apesar de não alterar parâmetros biométricos, parâmetros histomorfométricos ou a função contrátil dos cardiomiócitos. CONCLUSÃO: Nossos resultados indicam que o TR parcialmente neutraliza o remodelamento cardíaco adverso induzido pela DH, aumentando a atividade dos marcadores de remodelamento estrutural; elevando a biogênese mitocondrial; reduzindo o estresse oxidativo, marcadores inflamatórios e estresse do retículo endoplasmático; e melhorando os parâmetros hemodinâmicos, antropométricos e metabólicos.

Effect of experimental pulmonary arterial hypertension on renal and bone parameters of rats submitted to resistance exercise training.

Pulmonary arterial hypertension (PAH) is characterized by right ventricular failure and diminished cardiac output, potentially leading to renal and bone impairments. In contrast, resistance exercise training (RT) offers cardiovascular and bone health benefits. This study aimed to assess the impacts of stable PAH induced by monocrotaline (MCT) and RT on renal morphometry, as well as bone morphometry and biomechanical properties in male Wistar rats. Four experimental groups, untrained control (UC, n=7), trained control (TC, n=7), untrained hypertensive (UH, n=7), trained hypertensive (TH, n=7), were defined. After the first MCT or saline injection (20 mg/kg), trained rats were submitted to a RT program (i.e., Ladder climbing), 5 times/week. Seven days later the rats received the second MCT or saline dose. After euthanasia, renal and femoral histomorphometry and femoral biomechanical properties were assessed. PAH reduced renal glomerular area and volume, which was prevented by the RT. While PAH did not harm the femoral morphometry, structural and mechanical properties, RT improved the femoral parameters (e.g., length, percentage of trabeculae and bone marrow, ultimte and yield loads). Experimental stable PAH promotes renal but not bone damages, whereas RT prevents renal deteriorations and improves the femoral morphological and biomechanical properties.

Combined physical training protects the left ventricle from structural and functional damages in experimental pulmonary arterial hypertension.

BACKGROUND: Under the adverse remodeling of the right ventricle and interventricular septum in pulmonary arterial hypertension (PAH) the left ventricle (LV) dynamics is impaired. Despite the benefits of combined aerobic and resistance physical trainings to individuals with PAH, its impact on the LV is not fully understood. OBJECTIVE: To test whether moderate-intensity combined physical training performed during the development of PAH induced by MCT in rats is beneficial to the LV's structure and function. METHODS: Male Wistar rats were divided into two groups: Sedentary Hypertensive Survival (SHS, n = 7); and Exercise Hypertensive Survival (EHS, n = 7) to test survival. To investigate the effects of combined physical training, another group of rats were divided into three groups: Sedentary Control (SC, n = 7); Sedentary Hypertensive (SH, n = 7); and Exercise Hypertensive (EH, n = 7). PAH was induced through an intraperitoneal injection of MCT (60 mg/kg). Echocardiographic evaluations were conducted on the 22nd day after MCT administration. Animals in the EHS and EH groups participated in a combined physical training program, alternating aerobic (treadmill running: 50 min, 60% maximum running speed) and resistance (ladder climbing: 15 climbs with 1 min interval, 60% maximum carrying load) exercises, one session/day, 5 days/week for approximately 4 weeks. RESULTS: The physical training increased survival and tolerance to aerobic (i.e., maximum running speed) and resistance (i.e., maximum carrying load) exertions and prevented reductions in ejection fraction and fractional shortening. In addition, the physical training mitigated oxidative stress (i.e., CAT, SOD and MDA) and inhibited adverse LV remodeling (i.e., Collagen, extracellular matrix, and cell dimensions). Moreover, the physical training preserved the amplitude and velocity of contraction and hindered the reductions in the amplitude and velocity of the intracellular Ca2+ transient in LV single myocytes. CONCLUSION: Moderate-intensity combined physical training performed during the development of MCT-induced PAH in rats protects their LV from damages to its structure and function and hence increases their tolerance to physical exertion and prolongs their survival.

O Treinamento Resistido Atenua a Remodelação Cardíaca Induzida por uma Dieta Hiperlipídica em Roedores: Uma Revisão Sistemática / Resistance Exercise Training Mitigates Cardiac Remodeling Induced by a High-Fat Diet in Rodents: A Systematic Review

Resumo Fundamento A obesidade está associada ao desenvolvimento de doenças cardiovasculares e constitui um grave problema de saúde pública. Em modelos animais, a alimentação com uma dieta hiperlipídica (DH) compromete a estrutura e a função cardíaca e promove estresse oxidativo e apoptose. O treinamento resistido (TR), entretanto, tem sido recomendado como coadjuvante no tratamento de doenças cardiometabólicas, incluindo a obesidade, porque aumenta o gasto energético e estimula a lipólise. Objetivo Na presente revisão sistemática, nosso objetivo foi avaliar os benefícios do TR no coração de ratos e camundongos alimentados com DH. Métodos Foram identificados estudos originais por meio de busca nas bases de dados PubMed, Scopus e Embase de dezembro de 2007 a dezembro de 2022. O presente estudo foi conduzido de acordo com os critérios estabelecidos pelo PRISMA e registrado no PROSPERO (CRD42022369217). O risco de viés e a qualidade metodológica foram avaliados pelo SYRCLE e CAMARADES, respectivamente. Os estudos elegíveis incluíram artigos originais publicados em inglês que avaliaram desfechos cardíacos em roedores submetidos a mais de 4 semanas de TR e controlados por um grupo controle sedentário alimentado com DH (n = 5). Resultados Os resultados mostraram que o TR atenua o estresse oxidativo cardíaco, a inflamação e o estresse do retículo endoplasmático. Também modifica a atividade de marcadores de remodelamento estrutural, apesar de não alterar parâmetros biométricos, parâmetros histomorfométricos ou a função contrátil dos cardiomiócitos. Conclusão Nossos resultados indicam que o TR parcialmente neutraliza o remodelamento cardíaco adverso induzido pela DH, aumentando a atividade dos marcadores de remodelamento estrutural; elevando a biogênese mitocondrial; reduzindo o estresse oxidativo, marcadores inflamatórios e estresse do retículo endoplasmático; e melhorando os parâmetros hemodinâmicos, antropométricos e metabólicos.

Abstract Background Obesity is associated with the development of cardiovascular diseases and is a serious public health problem. In animal models, high-fat diet (HFD) feeding impairs cardiac structure and function and promotes oxidative stress and apoptosis. Resistance exercise training (RT), however, has been recommended as coadjutant in the treatment of cardiometabolic diseases, including obesity, because it increases energy expenditure and stimulates lipolysis. Objective In this systematic review, we aimed to assess the benefits of RT on the heart of rats and mice fed HFD. Methods Original studies were identified by searching PubMed, Scopus, and Embase databases from December 2007 to December 2022. This study was conducted in accordance with the criteria established by PRISMA and registered in PROSPERO (CRD42022369217). The risk of bias and methodological quality was evaluated by SYRCLE and CAMARADES, respectively. Eligible studies included original articles published in English that evaluated cardiac outcomes in rodents submitted to over 4 weeks of RT and controlled by a sedentary, HFD-fed control group (n = 5). Results The results showed that RT mitigates cardiac oxidative stress, inflammation, and endoplasmic reticulum stress. It also modifies the activity of structural remodeling markers, although it does not alter biometric parameters, histomorphometric parameters, or the contractile function of cardiomyocytes. Conclusion Our results indicate that RT partially counteracts the HFD-induced adverse cardiac remodeling by increasing the activity of structural remodeling markers; elevating mitochondrial biogenesis; reducing oxidative stress, inflammatory markers, and endoplasmic reticulum stress; and improving hemodynamic, anthropometric, and metabolic parameters.

Effects of physical training on hypothalamic neuronal activation and expressions of vasopressin and oxytocin in SHR after running until fatigue.

To assess the influence of physical training on neuronal activation and hypothalamic expression of vasopressin and oxytocin in spontaneously hypertensive rats (SHR), untrained and trained normotensive rats and SHR were submitted to running until fatigue while internal body and tail temperatures were recorded. Hypothalamic c-Fos expression was evaluated in thermoregulatory centers such as the median preoptic nucleus (MnPO), medial preoptic nucleus (mPOA), paraventricular nucleus of the hypothalamus (PVN), and supraoptic nucleus (SON). The PVN and the SON were also investigated for vasopressin and oxytocin expressions. Although exercise training improved the workload performed by the animals, it was reduced in SHR and followed by increased internal body temperature due to tail vasodilation deficit. Physical training enhanced c-Fos expression in the MnPO, mPOA, and PVN of both strains, and these responses were attenuated in SHR. Vasopressin immunoreactivity in the PVN was also increased by physical training to a lesser extent in SHR. The already-reduced oxytocin expression in the PVN of SHR was increased in response to physical training. Within the SON, neuronal activation and the expressions of vasopressin and oxytocin were reduced by hypertension and unaffected by physical training. The data indicate that physical training counterbalances in part the negative effect of hypertension on hypothalamic neuronal activation elicited by exercise, as well as on the expression of vasopressin and oxytocin. These hypertension features seem to negatively influence the workload performed by SHR due to the hyperthermia derived from the inability of physical training to improve heat dissipation through skin vasodilation.

Normal gastrointestinal temperature values measured through ingestible capsules technology: a systematic review.

Climate change has amplified the importance of continuous and precise body core temperature (Tcore) monitoring in the everyday life. In this context, assessing Tcore through ingestible capsules technology, i.e., gastrointestinal temperature (Tgastrointestinal), emerges as a good alternative to prevent heat-related illness. Therefore, we conducted a systematic review to point out values of normal Tgastrointestinal measured through ingestible capsules in healthy humans. The study followed PRISMA guidelines and searched the PubMed and Scielo databases from 1971 to 2023. Our search strategy included the descriptors ("gastrointestinal temperature") AND ("measurement"), and eligible studies had to be written in English and measured Tgastrointestinal using ingestible capsules or sensors in healthy adults aged 18-59 at rest. Two pairs of researchers independently reviewed titles and abstracts and identified 35 relevant articles out of 1,088 in the initial search. An average value of 37.13 °C with a standard deviation of 0.24 °C was observed, independently of the gender. The values measured ranged from 36.70 °C to 37.69 °C. In conclusion, this systematic review pointed out the mean value of 37.13 ± 0.24 °C measured by ingestible capsules as reference for resting Tgastrointestinal in healthy adult individuals.

O Treinamento Físico Resistido Atenua as Disfunções Ventriculares Esquerdas em Modelo de Hipertensão Arterial Pulmonar / Resistance Exercise Training Mitigates Left Ventricular Dysfunctions in Pulmonary Artery Hypertension Model

Resumo Fundamento A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo interventricular. Objetivo Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT). Métodos Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05. Resultados O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT. Conclusão O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.

Abstract Background The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. Objective To investigate whether low- to moderate-intensity resistance exercise training (RT) is beneficial to LV and cardiomyocyte contractile functions in rats during the development of monocrotaline (MCT)-induced PAH. Methods Male Wistar rats (Body weight: ~ 200 g) were used. To assess the time to potential heart failure onset (i.e., end point), rats were divided into sedentary hypertension until failure (SHF, n=6) and exercise hypertension until failure (EHF, n=6) groups. To test RT effects, rats were divided into sedentary control (SC, n = 7), sedentary hypertension (SH, n=7), and exercise hypertension (EH, n=7) groups. PAH was induced by two MCT injections (20 mg/kg, with 7 days interval). Exercise groups were submitted to an RT protocol (Ladder climbing; 55-65% of carrying maximal load), 5 times/week. Statistical significance was assumed at P < 0.05. Results RT prolonged the end point (~25 %), enhanced the physical effort tolerance (~ 55%), and mitigated the LV and cardiomyocyte contractility dysfunctions promoted by MCT by preserving the ejection fraction and fractional shortening, the amplitude of shortening, and the velocities of contraction and relaxation in cardiomyocytes. RT also prevented increases in left ventricle fibrosis and type I collagen caused by MCT, and maintained the type III collagen and myocyte dimensions reduced by MCT. Conclusion Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.

Is the Wistar Rat a more Suitable Normotensive Control for SHR to Test Blood Pressure and Cardiac Structure and Function?

Abstract Background: There are divergences in the literature regarding the experimental model (Wistar-WIS or Wistar Kyoto-WKY) to be used as a Spontaneously Hypertensive Rat (SHR) control. The characterization of these models in terms of cardiovascular parameters provides researchers with important tools at the time of selection and application in scientific research. Objective: The aim of this study was to evaluate the use of WIS and WKY as a Spontaneously Hypertensive Rat (SHR) control by assessing the long-term behavior of blood pressure and cardiac structure and function in these strains. Methods: To this end, WIS, WKY, and SHR underwent longitudinal experiments. Blood pressure and body mass were measured every two weeks from the 8th to the 72nd. Echocardiographic analysis was performed in all groups with 16, 48, and 72 weeks of life. After having applied the normality test, the Two-Way ANOVA of repeated measures followed by the Tukey post hoc test was used. A significance level of 5% was established. Results: The WIS group showed higher body mass (p<0.05), while the WKY and SHR presented higher body mass variation over time (p<0.05). SHR exhibited increased values of systolic, diastolic, and mean blood pressure when compared to WKY and WIS, whereas the WKY generally showed higher values than WIS (p<0.05). Regarding the cardiac function, SHR showed reduced values, while the WKY presented an early decrease when compared to WIS with aging (p<0.05). Conclusion: WIS is a more suitable normotensive control for SHR than WKY in experiments to test blood pressure and cardiac structure and function.

Effects of β-hydroxy-β-methylbutyrate (hmb) and resistance training on body fat and lipid metabolism signaling pathways

ABSTRACT Excess body fat is a serious problem for increasing the risk of cardiovascular diseases such as obesity, compromising the health and quality of life of the population. In this sense, resistance training (RT) is type of physical exercise which improves body composition by increasing lean mass and reducing fat mass. RT in combination with nutrition (i.e. protein supplementation) is a key intervention to improve body fat metabolism and reducing obesity. Concerning protein supplementation, the β-hydroxy-β-methylbutyrate (HMB) is a metabolite of the branched-chain amino acid leucine that has demonstrated positive effects on body fat reduction. However, the effects of combining HMB supplementation with RT related to adipose tissue metabolic activity are controversial and warrant further investigation. This study analyzed the effects of HMB supplementation associated with RT on body fat concentration and lipid metabolism signaling pathways.

RESUMEN El exceso de grasa corporal es un problema grave que aumenta tu riesgo de enfermedades y problemas de salud, tales como enfermedad cardíaca, diabetes, presión arterial alta y ciertos tipos de cáncer. En este sentido, y dentro del ejercicio físico, el entrenamiento de resistencia (ER) es un tipo de entrenamiento con pesos que mejora la composición corporal aumentando la masa magra y perdiendo masa grasa. El ER asociado con la nutrición (ej. suplementación proteica) es una excelente intervención para mejorar el metabolismo de los lípidos al reducir la grasa corporal. En relación con la suplementación proteica el β-hidroxi-β-metilbutirato (HMB) es un metabolito del aminoácido de cadena ramificada esencial leucina que ha demostrado efectos positivos en la reducción de grasa corporal. Sin embargo, los efectos de la suplementación con HMB asociados con TR relacionados con la actividad metabólica del tejido adiposo son controvertidos y necesita la realización de investigaciones adicionales. Este estudio analizó los efectos de la suplementación con HMB asociados con TR en la concentración de grasa corporal y en las vías de señalización que participan en la regulación del metabolismo de los lípidos.

Aerobic Exercise Increases the Damage to the Femoral Properties of Growing Rats with Protein-Based Malnutrition

Abstract The present study investigated the effects of aerobic physical training on the femoral morphological, densitometric and biomechanical properties in growing male rats subjected to protein-based malnutrition. Four-week-old male Wistar rats were randomized into groups of 10 animals: Control Sedentary (CS), Control Trained (CT), Malnourished Sedentary (MS) and Malnourished Trained (MT). Control and malnourished animals received diets with 12% protein and 6% protein, respectively. The trained groups were submitted to a treadmill running program for 8 weeks. Total proteins and albumin were analyzed in the animals' blood plasma. Histological, densitometric and biomechanical analyzes were performed on the animals' femur. Body mass gain, physical performance, biochemical markers and the femoral morphological, densitometric and biomechanical properties were determined. Exercise tolerance increased in trained groups. Malnourished animals exhibited lower serum protein and albumin levels than controls. Porosity and trabecular bone density were not different between groups. The femoral maximum load, maximum load until fracture, resilience, stiffness, tenacity and densitometric properties were reduced by malnutrition. Physical training associated with malnutrition exacerbated the impairment in the femoral maximum load, maximum load until fracture, bone mineral content and density. Aerobic physical training worsens the damages induced by protein-based malnutrition in the femoral biomechanical and densitometric properties of growing male rats.

Aerobic exercise attenuates the effects of ovariectomy and sedentarism on body composition and food intake in female rats / Exercício aeróbico atenua os efeitos da ovariectomia e do sedentarismo na composição corporal e no consumo alimentar em ratas

ABSTRACT Objective To evaluate the impact of low to moderate aerobic exercise and ovariectomy on body composition and food consumption in female rats. Methods Forty adult Wistar female rats (age: 23 weeks; body weight: 275.2±3.6g; mean±SEM) were divided into 4 groups (n=10): laparotomy-sedentary; laparotomy-exercised; ovariectomy-sedentary; and ovariectomy-exercised. The exercised groups were submitted to a treadmill running program (16m/min; 30min/day, 5 days/week), for 8 weeks. Body weight and food consumption were monitored during the experiment. Visceral fat and carcass water, protein, ash, fat and carbohydrate fractions were analyzed. Two-way ANOVA plus the Tukey's post hoc test was used for comparisons and p<0.05 was considered significant. Results The ovariectomized (ovariectomy-sedentary+ovariectomy-exercised) and sedentary (laparotomy-sedentary+ovariectomy-sedentary) animals showed higher (p<0.05) weight gain, food consumption, food efficiency ratio and weight gain/body weight ratio than laparotomy animals (laparotomy-sedentary+laparotomy-exercised) and exercised (exercised laparotomy+exercised ovariectomy), respectively. The ovariectomized and sedentary animals showed higher (p<0.05) carcass weight, fat percentage and visceral fat than laparotomy and exercised rats, respectively. Conclusion Ovariectomy and physical inactivity increase obesogenic indicators, whereas regular aerobic exercise of low to moderate intensity attenuates these unfavorable effects in female rats.

RESUMO Objetivo Avaliar o impacto do exercício aeróbico de intensidade baixa a moderada e da ovariectomia na composição corporal e no consumo alimentar em ratas. Métodos Quarenta ratas Wistar adultas (idade: 23 semanas; peso corporal: 275, 2±3, 6g; média±EPM) foram divididas em 4 grupos (n=10): laparotomia-sedentária, laparotomia-exercitada, ovariectomia-sedentária e ovariectomia-exercitada. Os grupos laparotomia-exercitada e ovariectomia-exercitada foram submetidos a um programa de corrida em esteira (16m/mim; 30min/dia, 5 dias/semana) durante 8 semanas. Foram monitorados o peso corporal e o consumo alimentar das ratas durante o experimento. Analisaram-se as frações de água, proteínas, cinzas, gordura e carboidrato da carcaça, bem como a gordura visceral. Empregou-se ANOVA Two-Way, seguida do teste post hoc de Tukey para as análises estatísticas. Adotou-se o nível de significância de p<0,05. Resultados As ratas ovariectomizadas (ovariectomia-sedentária+ovariectomia-exercitada) e sedentárias (laparotomia-sedentária+ ovariectomia-sedentária) exibiram maior (p<0,05) ganho de peso, consumo alimentar, coeficiente de eficácia alimentar e taxa de ganho de peso/peso corporal do que as ratas laparotomizadas (laparotomia-sedentária+laparotomia-exercitada) e exercitadas (laparotomia-exercitada+ovariectomia-exercitada), respectivamente. A carcaça das ratas ovariectomizadas e sedentárias apresentaram maior (p<0,05) peso, percentual de gordura e gordura visceral do que as ratas laparotomizadas e exercitadas, respectivamente. Conclusão A ovariectomia e o sedentarismo elevam indicadores obesogênicos, enquanto que o exercício aeróbico regular de intensidade baixa a moderada atenua esses efeitos desfavoráveis em ratas.

Thermoregulation in Hypertensive Rats during Exercise: Effects of Physical Training / Termorregulação durante o Exercício em Ratos Hipertensos: Efeitos do Treinamento Físico

Abstract Background: Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise. Objective: To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive rats undergoing an acute exercise protocol. Methods: Sixteen-week-old male Wistar rats and SHR were allocated into four groups: control Wistar rats (C-WIS), trained Wistar (T-WIS), control SHR (C-SHR) and trained SHR (T-SHR). Treadmill exercise training was performed for 12 weeks. Blood pressure, resting heart rate and total exercise time was measured before and after the physical exercise program. After the exercise program, a temperature sensor was implanted in the abdominal cavity, and the animals subjected to an acute exercise protocol, during which internal body temperature, tail skin temperature and oxygen consumption until fatigue were continuously recorded. Mechanical efficiency (ME), work, heat dissipation threshold and sensitivity were calculated. Statistical significance was set at 5%. Results: Physical training and hypertension had no effect on thermal balance during physical exercise. Compared with C-WIS, the T-WIS group showed higher heat production, which was counterbalanced by higher heat dissipation. Hypertensive rats showed lower ME than normotensive rats, which was not reversed by the physical training. Conclusion: Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.

Resumo Fundamento: Ratos espontaneamente hipertensos (SHR) apresentam déficits no balanço térmico durante o exercício físico. Objetivo: Avaliar os efeitos do treinamento físico de baixa intensidade sobre o balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo. Métodos: Ratos machos Wistar e SHR, com 16 semanas de idade, foram divididos em quatro grupos experimentais: Wistar controle (WIS-C), Wistar treinado (WIS-T), SHR controle (SHR-C) e SHR treinado (SHR-T). O treinamento físico em esteira rolante foi realizado durante 12 semanas. A pressão arterial, a frequência cardíaca de repouso e o tempo de exercício foram medidos previamente e após o programa de treinamento físico. Após o programa de treinamento físico, um sensor de temperatura foi implantado na região intraperitoneal e os ratos foram submetidos a um protocolo de exercício físico agudo com registros contínuos da temperatura corporal interna, temperatura da pele da cauda e do consumo de oxigênio até a fadiga. A eficiência mecânica (EM), o trabalho, o limiar e a sensibilidade para dissipação de calor foram calculados. Para as análises estatísticas o nível de significância adotado foi de 5%. Resultados: O treinamento físico e a hipertensão arterial não alteraram o balanço térmico durante o exercício físico. O grupo WIS-T quando comparado ao WIS-C, apresentou maior produção de calor, que foi contrabalanceado por uma maior dissipação de calor. Os animais hipertensos apresentaram menor EM em comparação aos animais normotensos, e o treinamento físico não foi capaz de reverter esta alteração. Conclusão: O treinamento físico de baixa intensidade não provocou alterações no balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo.

Estresse térmico ambiental e termorregulação em jogadores de futebol: uma revisão sistemática / Environmental thermal stress and thermoregulation in soccer players: a systematic review / Estrés térmico ambiental y termorregulación en jugadores de fútbol: una revisión sistemática

Resumo O objetivo do estudo foi fazer uma revisão sistemática acerca dos efeitos do estresse térmico ambiental sobre a termorregulação em jogadores de futebol. Foram avaliados estudos em bases de dados pertencentes ao portal Periódicos Capes. Foi empregado o método Prisma para o desenvolvimento da revisão. Jogadores de futebol apresentam grande aumento da temperatura corporal associada à redução de desempenho físico durante o jogo em ambiente quente. Em relação às estratégias para amenizar esse prejuízo (ex. resfriamento, hidratação, aclimatação e aquecimento), o pequeno número de trabalhos encontrado (n = 18) apresenta resultados controversos, portanto são necessários mais estudos.

Abstract The objective of the study was to systematically review the effects of the environmental thermal stress on thermoregulation in soccer players. We analyzed studies from databases belonging to the Periódicos Capes portal. The PRISMA method was used to perform the review. Soccer players exhibit high increase in body temperature associated with reduction in physical performance during game in warm environment. Concerning strategies to mitigate such impairment (e.g. cooling, hydration, acclimatization, warm up and heating), the small number of studies analyzed (n = 18) showed controversial results, which warrants more studies.

Resumen El objetivo del estudio fue llevar a cabo una revisión sistemática sobre los efectos del estrés térmico ambiental en la termorregulación de jugadores de fútbol. Se evaluaron estudios en bases de datos pertenecientes al portal Periódicos Capes. Se empleó el método PRISMA para el desarrollo de la revisión. Los jugadores de fútbol presentan un gran aumento de la temperatura corporal asociada con la reducción de rendimiento físico durante el juego en un entorno caluroso. En cuanto a las estrategias para disminuir esta alteración (p. ej., enfriamiento, hidratación, aclimatación y calentamiento), el pequeño número de trabajos encontrados (n= 18) presentan resultados controvertidos, por lo que es necesaria la realización de más estudios.

Swimming training potentiates the recovery of femoral neck strength in young diabetic rats under insulin therapy

OBJECTIVE: To test whether swimming training benefits femoral neck strength in young diabetic rats under insulin therapy. METHODS: A total of 60 male Wistar rats (age: 40 days) were divided equally into the following six groups: control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary plus insulin and diabetic exercise plus insulin. Diabetes was induced with a unique intraperitoneal injection (60 mg/kg body weight) of streptozotocin. Seven days after the injection and after 12 hours of fasting, the animals with blood glucose levels ≥300 mg/dL were considered diabetic. Seven days after the induction of diabetes, the animals in the exercise groups were subjected to progressive swimming training (final week: 90 min/day; 5 days/week; 5% load) for eight weeks. The animals in the insulin groups received a daily dose of insulin (2-4 U/day) for the same period. RESULTS: Severe streptozotocin-induced diabetes reduced the structural properties of the femoral neck (trabecular bone volume, trabecular thickness and collagen fiber content). The femoral neck mechanical properties (maximum load and tenacity) were also impaired in the diabetic rats. Insulin therapy partially reversed the damage induced by diabetes on the structural properties of the bone and mitigated the reductions in the mechanical properties of the bone. The combination of therapies further increased the femoral neck trabecular bone volume (∼30%), trabecular thickness (∼24%), collagen type I (∼19%) and type III (∼13%) fiber contents, maximum load (∼25%) and tenacity (∼14%). CONCLUSIONS: Eight weeks of swimming training potentiates the recovery of femoral neck strength in young rats with severe streptozotocin-induced diabetes under insulin therapy.

Physical Exercise and Regulation of Intracellular Calcium in Cardiomyocytes of Hypertensive Rats / Exercício Físico e Regulação de Cálcio Intracelular em Cardiomiócitos de Ratos Hipertensos

Abstract Background: Regulation of intracellular calcium (Ca2+) in cardiomyocytes is altered by hypertension; and aerobic exercise brings benefits to hypertensive individuals. Objective: To verify the effects of aerobic exercise training on contractility and intracellular calcium (Ca2+) transients of cardiomyocytes and on the expression of microRNA 214 (miR-214) in the left ventricle of spontaneously hypertensive rats (SHR). Methods: SHR and normotensive Wistar rats of 16 weeks were divided into 4 groups -sedentary hypertensive (SH); trained hypertensive (TH); sedentary normotensive (SN); and trained normotensive (TN). Animals of the TH and TN groups were subjected to treadmill running program, 5 days/week, 1 hour/day at 60-70% of maximum running velocity for 8 weeks. We adopted a p ≤ 0.05 as significance level for all comparisons. Results: Exercise training reduced systolic arterial pressure in hypertensive rats. In normotensive rats, exercise training reduced the time to 50% cell relaxation and the time to peak contraction and increased the time to 50% decay of the intracellular Ca2+ transients. In SHR, exercise increased the amplitude and reduced the time to 50% decay of Ca2+ transients. Exercise training increased the expression of miR-214 in hypertensive rats only. Conclusion: The aerobic training applied in this study increased the availability of intracellular Ca2+ and accelerated the sequestration of these ions in left ventricular myocytes of hypertensive rats, despite increased expression of miR-214 and maintenance of cell contractility.

Resumo Fundamento: A regulação intracelular de cálcio (Ca2+) em cardiomiócitos é alterada pela hipertensão, e o exercício físico aeróbico traz benefícios para hipertensos. Objetivo: Verificar os efeitos do treinamento físico aeróbico sobre a contratilidade e a concentração intracelular de Ca2+ transitória em miócitos e a expressão do microRNA 214 no ventrículo esquerdo (VE) de ratos espontaneamente hipertensos (SHR). Métodos: SHR e ratos Wistar normotensos com 16 semanas de idade foram divididos em 4 grupos de 13 animais cada: hipertenso sedentário (HS); hipertenso treinado (HT); normotenso sedentário (NS); normotenso treinado (NT). Os animais dos grupos HT e NT foram submetidos a um programa de treinamento progressivo de corrida em esteira, 5 dias/semana, 1 hora/dia, em intensidade de 60-70% da velocidade máxima de corrida, durante 8 semanas. Adotou-se p ≤ 0,05 como nível de significância em todas as comparações. Resultados: O treinamento físico reduziu a pressão arterial sistólica nos animais hipertensos. Nos animais normotensos, o treinamento físico reduziu o tempo para 50% de relaxamento celular e o tempo para o pico de contração celular, mas aumentou o tempo para 50% de decaimento da concentração intracelular de Ca2+ transitória. Nos animais SHR, o treinamento físico aumentou a amplitude e reduziu o tempo para 50% de decaimento da concentração intracelular de Ca2+ transitória, sem alterar a contratilidade celular. O treinamento físico aumentou a expressão do miR-214 apenas nos animais hipertensos. Conclusão: O treinamento aeróbico utilizado aumenta a disponibilidade e acelera o sequestro de Ca2+ intracelular em miócitos do VE de ratos hipertensos, apesar do aumento da expressão de miR-214 e da manutenção da contratilidade celular.

Moderate Continuous Aerobic Exercise Training Improves Cardiomyocyte Contractility in Β1 Adrenergic Receptor Knockout Mice / Treinamento Aeróbico Contínuo de Intensidade Moderada Melhora a Contratilidade do Cardiomiócito em Camundongos com Nocaute para o Receptor B1-Adrenérgico

Abstract Background: The lack of cardiac β1-adrenergic receptors (β1-AR) negatively affects the regulation of both cardiac inotropy and lusitropy, leading, in the long term, to heart failure (HF). Moderate-intensity aerobic exercise (MCAE) is recommended as an adjunctive therapy for patients with HF. Objective: We tested the effects of MCAE on the contractile properties of left ventricular (LV) myocytes from β1 adrenergic receptor knockout (β1ARKO) mice. Methods: Four- to five-month-old male wild type (WT) and β1ARKO mice were divided into groups: WT control (WTc) and trained (WTt); and β1ARKO control (β1ARKOc) and trained (β1ARKOt). Animals from trained groups were submitted to a MCAE regimen (60 min/day; 60% of maximal speed, 5 days/week) on a treadmill, for 8 weeks. P ≤ 0.05 was considered significant in all comparisons. Results: The β1ARKO and exercised mice exhibited a higher (p < 0.05) running capacity than WT and sedentary ones, respectively. The β1ARKO mice showed higher body (BW), heart (HW) and left ventricle (LVW) weights, as well as the HW/BW and LVW/BW than WT mice. However, the MCAE did not affect these parameters. Left ventricular myocytes from β1ARKO mice showed increased (p < 0.05) amplitude and velocities of contraction and relaxation than those from WT. In addition, MCAE increased (p < 0.05) amplitude and velocities of contraction and relaxation in β1ARKO mice. Conclusion: MCAE improves myocyte contractility in the left ventricle of β1ARKO mice. This is evidence to support the therapeutic value of this type of exercise training in the treatment of heart diseases involving β1-AR desensitization or reduction.

Resumo Fundamento: A falta de receptores β1-adrenérgicos (β1-AR) cardíacos afeta negativamente a regulação de inotropismo e lusitropismo cardíacos, levando, no longo prazo, a insuficiência cardíaca (IC). Recomenda-se exercício aeróbico contínuo de intensidade moderada (EACM) como adjuvante no tratamento de pacientes com IC. Objetivo: Testar os efeitos do EACM nas propriedades contráteis de miócitos do ventrículo esquerdo (VE) de camundongos com nocaute para o receptor β1-adrenérgico (β1ARKO). Método: Camundongos machos com 4 a 5 meses de idade, wild-type (WT) e β1ARKO foram divididos em grupos: WT controle (WTc) e treinado (WTt); e β1ARKO controle (β1ARKOc) e treinado (β1ARKOt). Os grupos treinados foram submetidos a regime de EACM (60 min/dia; 60% da velocidade máxima, 5 dias/semana) em esteira rolante, por 8 semanas. Adotou-se P ≤ 0,05 como nível de significância em todas as comparações. Resultados: Os animais β1ARKO (β1ARKOc + β1ARKOt) correram uma distância maior do que os animais WT (WTc + WTt) (p < 0,05). Os camundongos β1ARKO apresentaram maiores pesos corporal (PC), do coração (PCo) e do ventrículo esquerdo (PVE), assim como PCo/PC e PVE/PC do que os camundongos WT. Entretanto, o EACM não afetou tais parâmetros. Os miócitos do VE de camundongos β1ARKO apresentaram maiores (p < 0,05) amplitude e velocidades de contração e relaxamento do que os dos camundongos WT. Além disso, o EACM aumentou (p < 0,05) a amplitude e as velocidades de contração e relaxamento nos camundongos β1ARKO. Conclusão: O EACM melhora a contratilidade do miócito do VE de camundongos β1ARKO. Tal achado confirma o valor terapêutico desse tipo de treinamento físico para o tratamento de doenças cardíacas envolvendo dessensibilização ou redução de β1-AR.

Match internal load in youth elite soccer players is period, playing position and intermittent running capacity dependent

The aims of this study were: i) to verify whether player internal load (PIL) monitored via heart rate (HR) varies with game-time and playing position; ii) whether intermittent running capacity (IRC) is related to the maintenance of within-match PIL in elite youth (U-15) soccer players. Method: Twenty-one elite soccer players (14±0.5 yrs, 172±7 cm, 63±6 kg) had their heart rate monitored (beats/min) in five matches and were tested twice for IRC (Yo-YoIR2, distance [m]) over a seven-week competitive season. Percentage of maximal heart rate (%HRmax) and time spent (TS%) in five zones (Z1[<70%]; Z2[71-85%]; Z3[86-90%]; Z4[91-95%] and Z5[>96%]) were our PIL indexes. Data from three complete games in the same position of each player were analyzed and matches halves, time intervals (T1 to T6), and playing positions (fullbacks, central defenders and forwards [N=5 each], midfielders [N=6]) were compared, and the relationship between IRC and within-match PIL was determined. Results: PIL was higher in 1st (86±3%) than in the 2nd half (84±4%; p<.001). The 2nd half had more TS% in Z1 and Z2 (p<.05). PIL in T4 was the lowest (p<.01), and in T6, it was lower than T1 and T2 (p<.01). Fullbacks and midfielders showed higher PIL and higher TS% in Z4 (p<.05) than the other positional roles. The average IRC correlated with PIL in T6 (r=.56, p<.01) only. Conclusion: In conclusion, the internal load in elite youth (U-15) soccer players varies with game-time and playing position; and their IRC is related to the maintenance of within-match PIL.(AU)

Association of inflammation, dyslipidemia, obesity and physical activity status in children

The aim of this study was to verify the association between inflammatory biomarkers, dyslipidemia, obesity and physical activity status in 10-years old children. Ninety-four children participated in this study and were classified into eutrophic (n=36), overweight (n=34) or obese (n=24) according to their body mass index (BMI). The genic expression of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α) and chemokine C-C motif ligand 2 (CCL-2) mRNA; the serum concentration of high-density lipoprotein cholesterol (HDL-c) and triglycerides; BMI, percentage of body fat (% BF) and waist circumference; and the number of steps per day were determined. The expression of IL-6, TNF-α and CCL-2 were associated (p < 0.05) positively with serum triglycerides, BMI, % BF and waist circumference, and negatively with serum HDL-c. No association (p > 0.05) between pro-inflammatory biomarkers and number of steps per day was found