Walter Krause Neto

MORPHOLOGICAL ADJUSTMENTS OF THE RADIAL NERVE ARE INTENSITY-DEPENDENT

Introduccion: La adaptacion de los nervios perifericos es fundamental para el aumento de fuerza. Sin embargo, la informacion sobre el efecto de la intensidad sobre la morfologia del nervio es escasa. Objetivo: Comparar el efecto de diferentes intensidades de entrenamiento de resistencia en las estructuras del nervio radial. Metodos: Las ratas se dividieron en tres grupos: control (GC) y entrenamiento con 50% (GF1) y con 75% (GF2) del peso corporal del animal. El analisis morfologico del nervio se hizo con microscopia optica y electronica de transmision. Se aplicaron la prueba ANOVA de una via y la prueba post hoc de Tukey y el nivel de significacion se fijo en p ≤ 0,05. Resultados: Los grupos de entrenamiento tuvieron aumento de la fuerza con respecto al grupo control (p ≤ 0,05). Todos los componentes medidos del nervio (area media y diametro de las fibras de mielina y axones, area media y espesor de la vaina de mielina, neurofilamentos y microtubulos) fueron mayores en GF2 en comparacion con los otros grupos (p ≤ 0,05). Conclusion: Los resultados mostraron mayores cambios morfologicos en el nervio radial despues de las cargas mas pesadas. Esto puede ser importante para terapias de rehabilitacion, entrenamiento y progresion.

Use of Anabolic Steroid Altered the Liver Morphology of Rats

El objetivo fue investigar el efecto de la administracion de propionato de testosterona en el higado de ratas. Las ratas se dividieron en los siguientes grupos: control inicial (CI), control de Edad (CE) y grupo anabolico (GA). El propionato de testosterona se administro tres veces por semana durante 16 semanas. Utilizando tecnicas morfocuantitativas, determinamos las densidades de volumen del parenquima lobular y no lobular, area y numero de nucleos de los hepatocitos. Los datos fueron analizados estadisticamente con la media y desviacion estandar, la prueba de ANOVA de una via y un nivel de significacion p0,05. Nuestros resultados mostraron un aumento en los capilares, espacios perisinusoidales y conductos biliares en el grupo CE en comparacion con CI. El GA mostro una disminucion en las celulas hepaticas, la densidad de volumen no lobular y el area de los nucleos de hepatocitos, como tambien un aumento en los capilares, espacios perisinusoidales, conductos biliares, numero de hepatocitos y nucleos no hepatociticos en comparacion AL CI. Concluimos que una toxicidad directa puede haber ocurrido, con la consiguiente perdida de las celulas.

STRENGTH TRAINING AND ANABOLIC STEROID DO NOT AFFECT MUSCLE CAPILLARIZATION OF MIDDLE-AGED RATS

Introducao: Em geral, se aceita que a rede capilar diminui com o avanco da idade. O efeito combinado de treinamento resistido (TR) e testosterona ainda precisa ser elucidado. Objetivo: Este estudo visou medir o perfil capilar de diferentes musculos esqueleticos em ratos de meia-idade submetidos a TR e administracao de testosterona exogena. Metodos: Ratos Wistar foram divididos em cinco grupos experimentais: controle com ratos de 13 meses de idade (SC), controle com ratos de 16 meses de idade (SE), ratos idosos + anabolizante (SA), ratos idosos + TR (T) e ratos idosos + TR + anabolizante (TA) . Resultados: Para o musculo soleo, o grupo SE apresentou decrescimo do percentual de capilares em comparacao com o grupo SC. Os grupos SA, T e TA tiveram aumento do volume de capilares em comparacao com o SC. Por outro lado, para o musculo extensor longo dos dedos (ELD), os grupos SA, T e TA demonstraram menor volume e densidade numerica de capilares, em comparacao com SC e SE. O musculo ELD dos grupos T e TA apresentou 70% menos capilares do que o soleo. A densidade numerica e volumetrica e a razao de capilares por fibra muscular nao foram estatisticamente alteradas por nenhuma das intervencoes. A area de corte transversal (ACT) do musculo soleo dos grupos SA, T e TA foi estatisticamente diferente do grupo SC. A ACT do soleo foi maior nos grupos TA e T do que nos grupos SC, SE e SA e a ACT do ELD foi maior no grupo TA comparada com todos os outros grupos. O grupo TA teve valores maiores do que os grupos SE, SA e T. Conclusao: O tipo de intervencao usada nao afetou qualquer variavel mensurada do perfil capilar. Entretanto, o uso de esteroide anabolizante e/ou TR mostrou tendencia de diminuir a densidade de capilares no musculo ELD.

Total training load may explain similar strength gains and muscle hypertrophy seen in aged rats submitted to resistance training and anabolic steroids

Abstract This study aimed to quantify training parameters and analyze the morphological response of aged muscles submitted to resistance training and anabolic steroids. Aged Wistar rats were divided into groups: C – initial control; CF – final control; CAS – control with anabolic steroid, RT – resistance training, and RTA – resistance training with anabolic steroid. Maximum carried load, absolute and relative loads increased significantly in RT and RTA. RTA demonstrated greater relative load than RT. Average total volume, total climbing volume, relative total volume, relative total climbing volume, and mean climbing volume were similar between groups RT and RTA. For soleus, CAS, RT, and RTA enlarged cross-sectional area of type I fibers and nuclear ratio. As for type II fibers, RTA was higher than C and CF. For plantaris, RT and RTA showed significant increases in myofibers type I compared to C and CF. For type II fibers, RTA showed a significant increase compared to C and CF. Regarding the nuclear ratio, RT and RTA showed a higher ratio than C, CF, and CAS. Our results demonstrated that both RT and RTA were not different among the analyzed morphological parameters. This fact can be explained by the absence of differences found in the training variables analyzed.

Effects of testosterone administration on liver structure and function in aging rats

Abstract Aging males have a decrease in testosterone levels, by which the testosterone treatment may influence in a negatively fashion the liver. Aim: This study aimed to analyze the effects of aging with or without testosterone administration on the liver components of animals. Methods: Wistar rats were divided into three groups: 20 months’ group (G20), 24 months’ group (G24), group treated with testosterone for 16 weeks (GT). All groups were sacrificed at 24 months except for G20 that was sacrificed at 20 months. Results: Aging and testosterone treatment alters the body weight (BW), liver weight (LW) and relative liver weight. Besides, testosterone increased the mitogen capacity of hepatocytes. Nonetheless, we reinforce the negative effects of testosterone on old animals’ liver as chronic hepatic congestion and/or cholestasis. In addition, we observed that testosterone plays an important role on hepatic glycogen stores. Conclusions: Our study showed many implications for the knowledge about the effects of aging with or without testosterone administration on old animals’ liver.

Effects of Strength Training and Anabolic Steroid in the Peripheral Nerve and Skeletal Muscle Morphology of Aged Rats

Thirty male 20-month-old Wistar rats were divided into groups: IC—initial control (n = 6), FC—final control (n = 6), AC—anabolic hormone control (n = 6), ST—strength trained (n = 6) and STA—strength trained with anabolic hormone (n = 6). All groups were submitted to adaptation, familiarization and maximum load carrying test (MLCT). Strength training (6–8×/session with loads of 50%–100% MLCT, 3×/week and pause of 120 s) was performed in ladder climbing (LC) for 15 weeks. The administration of testosterone propionate (TP) was performed 2×/week (10 mg/kg) in animals in the AC and STA groups. After the experimental period, animals were euthanized and the tibial nerve and plantaris muscle removed and prepared for electron transmission and histochemistry. To compare the groups we used one-way ANOVA (post hoc Bonferroni), student’s t-tests for pre vs. post (dependent and independent variables) comparisons and significance level set at p ≤ 0.05. The following significant results were found: (a) aging decreased the number of myelinated axon fibers; (b) use of isolated TP increased the diameter of myelinated fibers, along with increased thickness of myelin sheath; (c) ST increased area of myelinated and unmyelinated fibers, together with the myelin sheath. These changes made it possible to increase the area occupied by myelinated fibers keeping their quantity and also reduce the interstitial space; and (d) association of anabolic steroid and ST increased the area of unmyelinated axons and thickness of the myelin sheath. Compared to ST, both strategies have similar results. However, Schwann cells increased significantly only in this strategy.

Endurance training induces structural and morphoquantitative changes in rat vagus nerve

Introduccion:Muchos tejidos del sistema nervioso y celulas sufren cambios positivos cuando se enfrentan con el entrenamiento fisico. Sin embargo, los datos sobre la adaptacion del nervio vago que resulta de los estudios con el ejercicio son ausentes.Objetivo:Analizar el efecto del entrenamiento de endurance en la morfologia del nervio vago de ratones.Metodo:Ratones Wistar (6 meses de edad) se dividieron en dos grupos: grupo control (GC, n= 8) y grupo con entrenamiento aerobico (TA, n=8). El grupo TA se sometio a un programa de entrenamiento sobre una cinta de correr cinco veces por semana durante 12 semanas. La velocidad maxima estipulada en el protocolo de entrenamiento correspondio al 60% de la intensidad media maxima alcanzada por el grupo en la prueba de ejercicio maximo.Resultados:Doce semanas de entrenamiento en una cinta resultaron en la hipertrofia ventricular en el grupo TA en comparacion con GC. Se obtuvo un aumento significativo en el area de ambos axones mielinizados y no mielinizados, y en el area de la vaina de mielina con entrenamiento. El numero de neurotubulos y neurofilamen-tos de fibras mielinizadas fue significativamente mayor en el grupo con entrenamiento aerobico en comparacion con GC (p = 0,05).Conclusion:El entrenamiento de endurance causo un aumento significativo en los parametros morfometricos del nervio vago en la misma forma en que afecta a los nervios somaticos.

Effects of exercise on neuromuscular junction components across age: systematic review of animal experimental studies

BackgroundDuring almost one-third of our life, maturation of the nervous system promotes strength and muscle mass increase. However, as age advances, the nervous system begins to suffer a slow and continue reduction of its functions. Neuromuscular junction (NMJ) is one of the structures of which change due to aging process. Physical training leads to significant adjustments in NMJs of young and aged animals. Nevertheless, studies that aimed to investigate this effect have, in many cases, methodological variables that may have some influence on the result. Thus, this study aimed to carry out a systematic review about the effects of exercise training on the NMJ compartments of young, adult and aged animals.ResultsWe searched PubMed, Google Scholar, Science Direct, Scielo and Lilacs databases for animal experimental studies that studied exercise effects on the NMJs components across age. After inclusion and exclusion criteria, we included nine articles in systematic review and two for meta-analysis (young/adult NMJ).ConclusionsWe identified that exercise training cause NMJ hypertrophy on young animals and NMJ compression on aged ones. However, many methodological issues such as age, skeletal muscle and fibers type, and type of exercise and training protocol might influence the results.Graphical abstract:Flow gram is actually to be show at results section as Fig 1

Effects of resistance training on liver structure and function of aged rats

Abstract The aging process may cause negative physiological changes. However, exercises as resistance training (RT) have been considered an important intervention to attenuate these changes. Additionally, liver plays an important role in blood glucose homeostasis in exercise. Aim: This study aimed to analyze the effects of RT on the liver components of aged animals. Methods: Male Wistar rats were divided into two groups: 24 months’ group (CONTROL); and group submitted to a progressive RT protocol for 16 weeks (EXERCISE). Both groups were sacrificed at 24 months. Results: We observed a decrease in blood flow due to the practice of resistance exercises. Besides, our results showed that hepatic tissue plays an important role in glycemic homeostasis during RT. In addition, RT increased mitogen capacity of hepatocytes. Conclusions: Our study showed many implications for the knowledge about the effects of strength training on old animals’ liver.

Chronic cachaça consumption affects the structure of tibial bone by decreasing bone density and density of mature collagen fibers in middle-aged Wistar rats

Abstract Several studies have demonstrated that alcohol consumption can decrease bone density and alter its structure. However, most of the studies did not investigate the effects of specific alcoholic beverages. This study determined the effects of chronic consumption of cachaça (a Brazilian beverage containing alcohol) on body weight (BW), tibia bone density and on the tibia collagen density in middle-aged Wistar rats. Rats with 9 months old were submitted for 100 days, to a liquid diet of cachaça diluted in water with a progressive and controlled concentration (10°GL, 15°GL, 20°GL, 25°GL, and 30°GL). Chronic cachaça intake produced a significant decrease in BW and altered bone remodeling, decreasing trabecular bone density. In chronic cachaça-treated group (CT), the production of collagen fibers in bone tissue has predominantly green birefringence. It appears that they are immature fibers that do not exist in the control group, in which there are standard predominantly yellowish mature fibers. In conclusion, chronic cachaça consumption affects the structure of the tibial bone of middle-aged rats by decreasing the bone density and reducing the density of mature collagen fibers.