Effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue: analysis by Raman spectroscopy, dual-energy X-ray absorptiometry, and mechanical resistance.

The aim of the present study was to verify the effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue by Raman spectroscopy (Raman), dual-energy X-ray absorptiometry (DXA), and mechanical resistance (F-max) analysis. A total of 40 male Wistar animals, 60 days old, were used. The animals were distributed into four groups: control (C), control with GH (GHC), muscular strength training (T), and muscular strength training with GH (GHT). Blood samples were collected for the quantification of creatine kinase (CK-MB) and the femurs were removed for analysis by Raman, DXA, and F-max. A more pronounced increase in the bone mineral components was verified in the T group, for all the variables obtained by the Raman (calcium, phosphate, amide, and collagen). In addition, for animals submitted to GH supplementation, there was a reduction in the variable bone mineral density (BMD) obtained by the DXA (p < 0.05). Finally, the animals that received GH supplementation presented a higher F-max, but without statistical significance (p > 0.05). It was concluded that animals that received GH supplementation demonstrated a decrease in BMD. In addition, T alone was able to promote increased calcium, phosphate, amide, and collagen compounds in bone tissue.

Alterations in morphology and aerobic resistance of rats subjected to different physical training protocols / Alteraciones en la morfología y resistencia aeróbica de animales sometidos a diferentes protocolos de entrenamiento

The objective of this study was to investigate the alterations in morphology and aerobic resistance of rats subjected to different physical training protocols. The study consisted of 55 rats of the "Wistar" breed, 100 days of age, over a period of 8 weeks. The animals were randomly distributed between four groups: control (CTLE); neuromuscular anaerobic (TAN); aerobic (TAE) and concurrent training (TCc). After four weeks, some of the animals were euthanized. The body mass index (BMI), Lee index (Lee), epididymal adipose tissue (TecAdp), body weight, and feed efficiency ratio (CoefAlim) were measured. The Anaerobic Threshold was determined by critical workload (7 %, 9 % and 11 % of body weight). TAE and TCc training caused alterations in Lee and BMI, at four and eight weeks respectively (LeeTAE=X:2.86±0.08; X:2.89±0.07 and LeeTCc=X:2.85±0.05; X:3.00±0.09). For the TecAdp, all groups presented a decrease, with the TCc value down after eight weeks (X:1.77±0.32). Finally, TAN training improved the CoefAlim (X:31.57±3.70) after the eight week period and the TCc presented the highest value for Lan (X:7.10±0.80).

El objetivo de este estudio fue investigar las alteraciones en la morfología y la resistencia aeróbica de animales sometidos a diferentes protocolos de entrenamiento. Se analizaron 55 ratas macho "Wistar" de 100 días de edad, durante un período de ocho semanas. Los animales fueron separados aleatoriamente en cuatro grupos: grupo control (CTLE); entrenamiento anaerobio neuromuscular (TAN); entrenamiento aerobio (TAE) y entrenamiento concurrente (TCc). Al término de cuatro semanas, algunos de los animales fueron sacrificados. Se midieron: índice de masa corporal (IMC), índice de Lee (Lee) y tejido adiposo del epidídimo (TecAdp), masa corporal y coeficiente de la eficacia alimentaria (CoefAlim). El umbral anaerobio (Lan) fue determinado por la carga crítica de trabajo (11, 9 y 7 % de la masa corporal). El entrenamiento TAE e TCc provocó alteraciones de Lee e IMC, en los períodos de cuatro y ocho semanas, respectivamente (LeeTAE=X:2,86±0,08; X:2,89±0,07 y LeeTCc=X:2,85±0,05; X:3,00±0,09). En relación a TecAdp, se observó una disminución en todos los grupos. Por último, el entrenamiento TAN mejoró en el período de ocho semanas para la variable CoefAlim (X:31,57±3,70) y el TCc con un valor mayor de Lan (X:7,10±0,80).

Physical exercise after immobilization of skeletal muscle of adult and aged rats / Exercício físico após imobilização de músculo esquelético de ratos adultos e idosos / Ejercicio físico después de la inmovilización del músculo esquelético de ratas adultas y mayores

ABSTRACT Introduction: Immobilization is a treatment technique often used to reduce pain and prevent worsening of the injury. However, it promotes harmful effects on musculoskeletal tissue, resulting in a marked loss of muscle function, which may be aggravated in the elderly. Physical exercise is an important intervention to mitigate these harmful effects. Objective: To analyze possible morphometric changes in the gastrocnemius muscle of rats after immobilization and remobilization with physical exercise. Methods: Fifty-six rats were divided into adult (A) and aged (E) groups and subdivided into adult and aged control (AC and EC), immobilized (AI and EI), free remobilized (AIF and EIF), and remobilized through physical exercise (AIE and EIE). The hind limbs were immobilized with the gastrocnemius muscle in a shortened position for a period of seven days, except for the control group. The exercise protocol consisted of five swimming sessions, once per day (25 minutes/session). The animals were euthanized by administration of an overdose of ketamine hydrochloride plus xylazine hydrochloride, followed by sample collection and preparation of hematoxylin and eosin slides. Measurements of the smallest diameter of 120 muscle fibers of each animal were taken with software NIS-Elements D3.0 - SP7 - Nikon® instruments Inc., NY, USA. Results: There was a significant reduction in the mean fiber diameter in the AI (38.43 µm ± 4.20; p=0.01) and AIF (36.97 µm ± 3.41; p<0.01) groups compared to AC (45.39 µm ± 3.41) and in the EI (42.26 µm ± 4.39; p<0.01), EIF (36.00 µm ± 4.15; p<0.01), and EIE (41.86 µm ± 4.95; p<0.01) groups compared to the EC (51.37 µm ± 3.86) group. The data showed that exercise was able to restore muscle trophism in the adult groups; however, none of the protocols has succeeded in aged rats. Conclusion: Immobilization in the shortened position induced muscle atrophy and physical exercise was effective in restoring muscular trophism only in adult animals. Level of Evidence I; Therapeutic studies - Investigating the Results of Treatment.

RESUMO Introdução: A imobilização é uma técnica de tratamento utilizada frequentemente para redução de dor e prevenção do agravamento da lesão. Entretanto, promove efeitos nocivos no tecido músculo-esquelético, resultando em perda acentuada de função muscular, que pode ser agravada em idosos. O exercício físico constitui intervenção importante para atenuar esses efeitos nocivos. Objetivo: Analisar possíveis alterações morfométricas no músculo gastrocnêmio de ratos após imobilização e remobilização com exercício físico. Métodos: Cinquenta e seis ratos divididos em grupo adulto (A) e grupo idoso (E) e subdivididos em controles adultos e idosos (AC e EC), imobilizado (AI e EI), remobilizado livre (AIF e EIF) e remobilizado por meio de exercício físico (AIE e EIE). Os membros traseiros foram imobilizados com o músculo gastrocnêmio em posição de encurtamento por um período de sete dias, exceto no grupo controle. O protocolo de exercícios foi composto por cinco sessões de natação uma vez por dia (25 minutos/sessão). Os animais foram submetidos à eutanásia por administração de cloridrato de cetamina em dose elevada e cloridrato de xilazina, seguida da coleta da amostra e preparação das lâminas com hematoxilina e eosina. Foram feitas as medidas do menor diâmetro de 120 fibras musculares de cada animal com o software NIS-Elements D3.0 - SP7 - Nikon® instruments Inc.®, NY, EUA. Resultados: Houve redução significante na média do diâmetro das fibras nos grupos AI (38,43 µm ± 4,20; p = 0,01) e AIF (36,97 µm ± 3,41; p < 0,01) com relação ao grupo AC (45,39 µm ± 3,41) e dos grupos EI (42,26 µm ± 4,39; p < 0,01), EIF (36,00 µm ± 4,15; p<0,01) e EIE (41,86 µm ± 4,95; p < 0,01) com relação ao grupo EC (51,37 µm ± 3,86). Os dados mostraram que o exercício foi capaz de restaurar o trofismo muscular nos grupos adultos; entretanto, nenhum dos protocolos teve sucesso nos ratos idosos. Conclusão: A imobilização em posição de encurtamento induziu à atrofia muscular e o exercício físico foi eficaz para restabelecer o trofismo muscular apenas nos animais adultos. Nível de Evidência I; Estudos terapêuticos - Investigação dos resultados do tratamento.

RESUMEN Introducción: La inmovilización es una técnica de tratamiento utilizada frecuentemente para reducir el dolor y prevenir el agravamiento de la lesión. Sin embargo, promueve efectos nocivos en el tejido músculo-esquelético, resultando en una pérdida acentuada de función muscular y puede agravarse en ancianos. El ejercicio físico constituye una intervención importante para atenuar estos efectos nocivos. . Objetivo: Analizar posibles cambios morfométricos en el músculo gastrocnemio de ratas después de la inmovilización y removilización con ejercicio físico. Métodos: Cincuenta y seis ratas divididas en grupo adulto (A) y mayores (E) y subdividas en controles adultos y mayores (AC y EC), inmovilizado (AI y EI), removilizado libre (AIF y EIF) y removilizados con ejercicio físico (AIE y EIE). Las extremidades traseras de los animales fueron inmovilizados con el músculo gastrocnemio en posición de acortamiento por un período de siete días, excepto en el grupo control. El protocolo de ejercicios se compuso de cinco sesiones de natación una vez el día (25 minutos/sesión). Los animales fueron sometidos a la eutanasia por administración de clorhidrato de ketamina en dosis elevada y clorhidrato de xilazina, seguida de la recolección de la muestra y preparación de las láminas con hematoxilina y eosina. Se realizaron las medidas del menor diámetro de 120 fibras musculares en cada animal con el programa NIS-Elements D3.0 - SP7 - Nikon® Instruments Inc. ® , NY, EE.UU. Resultados: Hubo una reducción significativa en la media del diámetro de las fibras en los grupos AI (38,43 µm ± 4,20; p = 0,01) y AIF (36,97 µm ± 3,41; p < 0,01) en comparación con el grupo AC (45,39 µm ± 3,41) y de los grupos EI (42,26 µm ± 4,39; p < 0,01), EIF (36,00 µm ± 4,15; p < 0,01) y EIE (41,86 µm ± 4,95; p < 0,01) con relación al grupo EC (51,37 µm ± 3,86). Los datos mostraron que el ejercicio fue capaz de restaurar el trofismo muscular en los grupos adultos; sin embargo, ninguno de los protocolos tuvo éxito en las ratas mayores. Conclusión: La inmovilización en posición de acortamiento indujo a la atrofia muscular y el ejercicio físico fue eficaz para restablecer el trofismo sólo en los animales adultos. Nivel de Evidencia I; Estudios Terapéuticos - Investigación de los resultados del Tratamento.

Histological analysis of the association of low level laser therapy and platelet-rich plasma in regeneration of muscle injury in rats.

OBJECTIVE: Muscle injuries are common, and their treatment requires costs and time off. Platelet rich plasma and low level laser therapy have been shown to be affordable and easy to use. The aim of this study was to evaluate the associated effects of low level laser therapy and platelet rich plasma on the treatment of the soleus muscle injured by strain in rats. METHODS: Thirty-five rats were randomly allocated into five groups: Control (C), Injury Control (IC), injury PRP (IP), injury LLLT (ILT) and injury LLLT and PRP (ILTP). The strain injury was induced in the soleus muscle and the IP group received application of platelet rich plasma immediately after the lesion, while the ILT group received low level laser therapy. After seven days, all animals were euthanized and the soleus muscle removed for further histological analysis. RESULTS: The association of both treatments (ILTP) resulted in better histological aspects than the low level laser therapy and platelet rich plasma alone, when compared with the injury group (IC). The collagen analysis exhibited a significant increase in the ILT group (2.99 SD=1.13) compared to the C (1.88 SD=0.41, p=0.012) and IP (2.04 SD=0.44, p=0.018). CONCLUSION: The association of low level laser therapy with platelet rich plasma produced better results on muscle injury compared to the isolated use of these therapies. Furthermore, none of the treatments could modulate the collagen deposition in relation to injury group.

Effects of concurrent training on muscle fibers of Wistar rats submitted to standard and hypercaloric diets / Efecto del entrenamiento concurrente en las fibras musculares de ratas Wistar sometidas a dietas normal e hipercalórica

To analyze the effects of concurrent training (CT) on the muscle fibers of Wistar rats submitted to standard and hypercaloric diets. In total, 40 rats were used, divided into 4 groups: Sedentary Group (GS); Exercise Group (GE), Obese Sedentary Group (OS) and Obese Exercise Group (OE). The animals performed a CT protocol consisting of: muscle strength training and aerobic training, carried out 3 times a week for 45 days. The smallest diameter of muscle fibers (MDF) was analyzed to evaluate muscle hypertrophy. It was observed that the OE group presented a significant decrease in MDF, compared to the OS group (OE=77.41 µm vs. OS=98.58 µm). In addition, the animals that performed CT demonstrated muscle hypertrophy (GE=74.39 µm vs. GS=72.13 µm). In conclusion, the CT with a standard diet promoted an increase in MDF while CT with a hypercaloric diet resulted in a decrease.

El objetivo de este trabajo fue analizar el efecto del entrenamiento concurrente (EC) en las fibras musculares de ratas Wistar sometidas a dietas normal e hipercalórica. Fueron utilizadas 40 ratas Wistar, distribuidas en cuatro grupos de animales: grupo sedentario (GS); grupo ejercicio (GE); grupo obeso sedentario (OS) y grupo obeso ejercicio (OE). Los animales realizaron el protocolo del EC compuesto por entrenamiento de fuerza y aeróbico, tres veces en la semana y por 45 días. La media del menor diámetro (MMD) de las fibras musculares fue medida para verificar la hipertrofia muscular. Fue observado que el grupo OE presentó una significante diminución del MMD comparado al grupo OS (OE=77.41 µm vs. OS=98.58 µm). Además, los animales que fueron sometidos al protocolo del EC demostraron hipertrofia muscular (GE=74.39 µm vs. GS=72.13 µm). Se puede concluir que el protocolo del EC con dieta normal tiene como resultado un aumento del MMD, mientras que el EC con dieta hipercalórica tiene como resultado la diminución del MMD.

Effects of aerobic, anaerobic, and concurrent training on bone mineral density of rats

Abstract A sample of 39 rats were divided into the following groups: baseline (BL); aerobic training (ET4 and ET8); anaerobic training (ST4 and ST8); and concurrent training (CT4 and CT8). The aerobic training was performed by swimming with a load corresponding to 70% of the anaerobic threshold; the anaerobic training was performed by jumping in water with a load corresponding to 50% of body weight; and the concurrent training combined the two protocols. The analysis of BMDwas performed on the tibia of the animals and showed an increase in the density of the ST4, CT4, ET8, ST8, and CT8 groups when compared with both the BL and ET4. Thus, it is concluded that anaerobic exercise was shown to be effective in increasing the BMD of animals afterfour weeks of training; however, aerobic training was only able to raise BMD following eight weeks of training.(AU)

Analysis of photobiomodulation associated or not with platelet-rich plasma on repair of muscle tissue by Raman spectroscopy.

Treatment of muscle injuries usually results in the interruption of sports practice; thus, studies aimed at accelerating the return to activity, with proper tissue repair, are important. Therefore, this study aimed to evaluate the effects of photobiomodulation (PBM), associated or not with platelet-rich plasma (PRP), on the treatment of muscle injury. Thirty-five animals were used and divided into five groups (n = 7): control (C), control lesion (CL), lesion treated with low-level laser therapy (LLLT) (LLt), lesion treated with PRP (LP), and lesion treated with both techniques, LLLT and PRP (LLtP). Muscle injury was induced by stretching the gastrocnemius muscle, and the animals in the LLtP and LP groups received the application of PRP immediately following the injury. The LLLT was applied daily for 7 days. The animals were euthanized 7 days after the injury. Analysis of the NADH/NAD ratio and collagen was performed by Raman spectroscopy; in addition to which, histological analysis of the gastrocnemius muscle was performed. The LLtP group demonstrated a reduction in the area of injury, regenerating cells and a healthy appearance of muscle fibers. The Raman analyses showed a reduction in the NADH/NAD ratio in the CL group, demonstrating oxidative stress, and the collagen presented a reduction in the CL and LLt groups, when compared with the C group. It is concluded that either PBM or PRP, and the association of both, was able to reduce the oxidative stress promoted by injury and modulate collagen production at the site of the injury. Furthermore, although both treatments individually were effective for repairing the damage caused by muscle injury, the association of both demonstrated a better histological aspect.

Morphometric and fractal analysis of injured skeletal muscle tissue subjected to a combination of treatments; cryotherapy and therapeutic ultrasound / Análisis de la morfometría y de la dimensión fractal en la lesión del tejido muscular esquelético expuesto en la combinación de los tratamientos de crioterapia y ultrasonido

The aim of this study was to analyze the effects of an association of cryotherapy and therapeutic ultrasound on the treatment of muscle injured by impact. Fifty-five Wistar rats were divided into five groups (n = 11), Acute Injury (AI), Injury (I), Cryotherapy (CR), Therapeutic Ultrasound (TU) and Association of Cryotherapy and Therapeutic Ultrasound (CRTU). The CR and CRTU groups received applications of Cryotherapy three times (immediately, 24 and 48 h after injury) of 20 minutes duration. The TU and CRTU groups received applications of Therapeutic Ultrasound for seven days, for five minutes, in pulsed mode, 0.5 w/cm intensity, frequency 1 MHz. Body mass and gastrocnemius mass were analyzed. In addition to histological slides stained with hematoxylin and eosin used for morphometric analysis, picrosirius dye was used for quantification of collagen by Fractal Dimension (FD). The results of the intra-group analysis showed lower body mass and gastrocnemius in the CRTU group in relation to the AI (p = 0.001), I (p = 0.001), CR (p = 0.001) and TU groups (p = 0.001), and lower values of FD to quantify collagen in the CRTU group in relation to the AI (p = 0.007) and CR groups (p = 0.014). In summary, the present study showed that the association of Cryotherapy with Therapeutic Ultrasound promoted better results in the aspects analyzed compared to application of the therapies in isolation.

El objetivo del estudio fue evaluar los efectos de la asociación de las técnicas de crioterapia y ultrasonido terapéutico en el tratamiento de la lesión muscular por impacto. Fueron utilizadas 55 ratas Wistar, expuestas a lesión y separadas en grupos (n = 11): Lesión aguda (LA), Lesión (L), Crioterapia (CR), Ultrasonido Terapéutico (UT) y Crioterapia + Ultrasonido Terapéutico (CRUT). Los grupos CR y CRUT recibieron la aplicación, durante 20 minutos, en tres momentos (inmediatamente, 24 y 48 horas, después de la lesión). Los grupos UT y CRUT, recibieron UT por siete días, con una duración de cinco minutos, en modo pulsado, con una intensidad de 0,5 W/cm2 y frecuencia de 1 MHz. Fueran medidos el peso corporal y el peso de los músculos gastrocnemios y se realizaron cortes histológicos del músculo gastrocnemio, los cuales fueron teñidos con hematoxilina-eosina (HE) para el análisis morfométrico y con picrosirius para el análisis del colágeno por dimensión fractal (DF). Los resultados de los análisis intragrupo demostraron una menor disminución de la masa coporal y muscular en el grupo CRUT. Además, fue observado un valor inferior en la morfometría en el grupo CRUT en comparación a los grupos LA (p = 0,001), L (p = 0,001), CR (p = 0,001) y UT (p = 0,001), y un menor valor de la DF con respecto al colágeno en el grupo CRUT en comparación a los grupos LA (p = 0,007) y CR (p = 0,014). En síntesis, el presente estudio demostró que el protocolo de asociación de las técnicas de CR y UT causaron mayores respuestas benéficas en los aspectos analizados en comparación a los protocolos con los tratamientos aplicados de forma aislada.

Effect of body composition on aerobic capacity of animals submitted to swimming exercise / Efeitos da composição corporal na capacidade aeróbia de animais submetidos ao exercício de natação

Abstract The aim of this study was to verify the influence of body composition on the CAER of animals submitted to different types of physical training. Twenty-three Wistar rats were divided into groups according to the training protocol: control (CTLE); aerobic training (TAE); anaerobic training (TAN); and concurrent physical training (TCc). The critical load test (CC) was carried out for determining the anaerobic threshold at the beginning and end of the training period. TAE was composed of swimming exercise with intensity corresponding to 70% of the anaerobic threshold; TAN was composed of water jumps with overload of 50% of the body weight of each animal; and TCc was composed of a combination of aerobic and anaerobic protocols described above. After four weeks of training, the weight of epididymal adipose tissue and soleus, plantar and gastrocnemius muscles was collected and measured. Dispersion analysis was used to draw graphics and analysis of the simple linear regression model was performed to identify the influence of each variable on CAER. Body Fat demonstrated positive influence of 5% on the relationship with the Anaerobic Threshold. Soleus and gastrocnemius muscles showed negative influence of 13.1% and 37.0%, respectively. The plantaris muscle showed no influence on the Anaerobic Threshold. Body composition influenced the CAER of the animals analyzed. Moreover, it was verified that body fat favored floatability, while higher muscle mass impaired it.

Resumo Objetivou-se verificar a influência da composição corporal na CAER de animais submetidos a diferentes tipos de treino físico. Foram utilizados 23 ratos Wistar, divididos em grupos de acordo com o protocolo de treino: controle (CTLE); treino aeróbio (TAE); treino anaeróbio (TAN); e treino físico concorrente (TCc). Foi realizado o Teste de carga crítica (CC) para a determinação do limiar anaeróbio no início e no final do período de treino. O TAE foi composto por exercício de natação com intensidade correspondente a 70% do Limiar Anaeróbio; o TAN por meio de saltos aquáticos com sobrecarga de 50% do peso corporal de cada animal; e o TCc pela combinação dos protocolos aeróbio e anaeróbio, descritos anteriormente. Após quatro semanas de treino, foi coletado e mensurado o peso do tecido adiposo epididimal e dos músculos sóleo, plantar e gastrocnêmio. Foi utilizada a análise de dispersão para a elaboração e gráficos e a análise do modelo de regressão linear simples para identificar a interferência de cada uma das variáveis na CAER. A Gordura Corporal demonstrou influência positiva de 5% na relação com o Limiar Anaeróbio. Os músculos sóleo e gastrocnêmio mostraram influência negativa de 13,1% e 37,0%, respectivamente. Enquanto o músculo plantar não mostrou qualquer influência no limiar anaeróbio. A composição corporal influenciou na CAER dos animais analisados. Além disso, notou-se que a gordura corporal favoreceu a flutuabilidade, enquanto a maior massa muscular a prejudicou.

Fractal analysis of skeletal muscle tissue of rats subjected to stretch injury / Análisis fractal de tejido muscular esquelético en ratas sometidas a lesión por estiramiento

The aim of this study was to analyze changes in the skeletal muscle tissue of rats after muscle stretch injury using fractal analysis. Nineteen rats were divided into three groups, Control (n= 5) (C), Lesion two days (n= 7) (L2), and Lesion seven days (n= 7) (L7). Histological slides of the gastrocnemius muscle of the animals were prepared and stained with Hematoxylin and eosin for analysis of the inflammatory process, and picrosirius for the demonstration of collagen. The stained slides were subsequently analyzed using Fractal Dimension (FD). The results showed high FD values of the inflammatory process in the experimental groups L2 and L7 in relation to C (p= 0.000). The analysis of collagen in the picrosirius stained slides showed high FD in the L2 group compared to the L7 (p= 0.0001), with no statistically significant difference among other groups. In summary, the present study demonstrated that fractal analysis was able to identify changes in the inflammatory process in injured skeletal muscle tissue.

El objetivo de la investigación fue observar las modificaciones en tejido muscular esquelético en ratas después de la lesión por estiramiento muscular con análisis fractal. En el estudio se incluyeron 19 ratas, divididas en tres grupos, Control (n= 5) (C), lesión dos días (n= 7) (L2) y lesión siete días (L7). Los cortes histológicos del músculo gastrocnemio fueron coloreados con hematoxilina-eosina para el análisis de la inflamación y picrosirius para la determinación del colágeno. Los cortes histológicos fueron posteriormente analizados por medio de dimensión fractal (FD). Los resultados mostraron valores elevados de FD en proceso inflamatorio en los grupos experimentales L2 y L7, en comparación con grupo C (p= 0,000). El análisis de colágeno mostró mayor FD en grupo L2 comparado con L7 (p= 0,0001), se observó diferencia estadísticamente significativa con los demás. En resumen, esta investigación ha demostrado que el análisis fractal fue capaz de identificar las alteraciones del proceso inflamatorio en tejido muscular esquelético después de la lesión.

Análise termogravimétrica da cartilagem articular de ratos exercitados após imobilização / Thermogravimetric analysis of articular cartilage of exercised rats after immobilization / Análisis termogravimétrico del cartílago articular de ratones ejercitados después de inmovilización

INTRODUÇÃO: A imobilização articular é uma técnica de tratamento frequentemente utilizada na ortopedia e, associada ao processo de senescência, promove alterações tanto na estrutura quanto na síntese e biomecânica do tecido cartilaginoso. OBJETIVO: Descrever os efeitos da imobilização, da remobilização livre e por meio de exercício físico sobre a cartilagem articular de ratos situados em duas faixas etárias. MÉTODOS: Trinta e nove ratos Wistar divididos em dois grupos etários, um grupo adulto (cinco meses de idade) e um idoso (15 meses de idade), subdivididos em: controle, imobilizado, remobilizado livre e remobilizado por meio de exercício físico. Os membros posteriores dos ratos foram imobilizados por sete dias. O protocolo de exercícios foi composto por cinco sessões diárias de natação, de 25 minutos cada. A cartilagem articular do quadril foi submetida à análise termogravimétrica, tendo sido avaliado seu conteúdo de água. RESULTADOS: Nos animais adultos a imobilização reduziu a quantidade de água presente no tecido cartilaginoso, e os protocolos de remobilização foram eficazes para restabelecer a condição inicial do tecido. Nos animais idosos não houve diferença significativa entre os grupos, porém o grupo idoso controle obteve resultado significantemente menor que o grupo adulto controle (X: 13,10 ± 5,24 vs 10,70 ± 1,95). CONCLUSÕES: A imobilização e o processo de senescência induzem a diminuição do conteúdo de água da cartilagem articular e os protocolos de remobilização foram eficientes para restabelecer esta propriedade apenas nos animais adultos. .

INTRODUCTION: Joint immobilization is a technique often used in orthopedic treatment and, associated with the aging process, promotes changes in both the structure and synthesis and biomechanics of cartilage tissue. OBJECTIVE: To describe the effects of immobilization, free remobilization and remobilization by physical exercise over articular cartilage of rats of two age groups. METHODS: Thirty nine Wistar rats divided into two groups according to age, an adult group (five months old) and an elderly group (15 months old), and subdivided into: control, immobilized, free remobilized and remobilized by physical exercise. The pelvic limb of rats was immobilized for seven days. The exercise protocol consisted of 25 minutes swimming sessions, five sessions per day. The hip articular cartilage was subjected to thermogravimetric analysis, and the water content was evaluated. RESULTS: In adult animals immobilization reduced the water content of the articular cartilage, and the remobilization protocols were effective to restore the initial condition of the tissue. In elderly animals there were not significant differences among the groups, however the elderly control group obtained results significantly lower than the adult control group (X: 13.10 ± 5.24 vs 10.70 ± 1.95). CONCLUSIONS: Immobilization and the senescence process induce the decrease of water content of articular cartilage and remobilization protocols were effective to restoring this property only in adult animals. .

INTRODUCCIÓN: La inmovilización articular es una técnica de tratamiento frecuentemente utilizada en ortopedia y asociada al proceso de senescencia, que promueve alteraciones tanto en la estructura como en la síntesis y la biomecánica del tejido cartilaginoso. OBJETIVO: Describir los efectos de la inmovilización, de la removilización libre y mediante el ejercicio físico sobre el cartílago articular de ratones de dos grupos de edad. MÉTODOS: Treinta y nueve ratones Wistar divididos en dos grupos de edad, un grupo adulto (cinco meses) y un grupo anciano (15 meses), y subdividos en control, inmovilizado, removilizado libre y removilizado a través de ejercicio físico. Los miembros posteriores de los ratones fueron inmovilizados durante un período de siete días. El protocolo de ejercicios fue compuesto por cinco sesiones diarias de natación, de 25 minutos cada una. El cartílago articular de la cadera fue sometido a análisis termogravimétrico, siendo evaluado su contenido de agua. RESULTADOS: En los animales adultos la inmovilización redujo la cantidad de agua presente en el tejido cartilaginoso, y los protocolos de removilización fueron eficaces para restablecer la condición inicial del tejido. En los animales ancianos no hubo diferencia significativa entre los grupos, aunque el grupo anciano control obtuvo resultado significativamente menor que el grupo adulto control (X: 13,10 ± 5,24 vs 10,70 ± 1,95). CONCLUSIONES: La inmovilización y el proceso de senescencia inducen la disminución en el contenido de agua de cartílago articular y los protocolos de removilización fueron eficientes para restablecer esta propiedad sólo en los animales adultos. .

Muscle mechanical properties of adult and older rats submitted to exercise after immobilization.

OBJECTIVES: To describe the effects of immobilization, free remobilization and remobilization by physical exercise about mechanical properties of skeletal muscle of rats of two age groups. METHODS: 56 Wistar rats divided into two groups according to age, an adult group (five months) and an older group (15 months). These groups were subdivided in: control, immobilized, free remobilized and remobilized by physical exercise. The pelvic limb of rats was immobilized for seven days. The exercise protocol consisted of five swimming sessions, once per day and 25 minutes per session. The gastrocnemius muscle was subjected to tensile tests, and evaluated the properties: load at the maximum limit, stretching at the maximum limit and stiffness. RESULTS: The immobilization reduced the values of load at the maximum limit and the remobilization protocols were not sufficient to restore control levels in adult group and older rats. The stretching at the maximum limit differs only in the older group. CONCLUSIONS: The immobilization reduces the muscle's ability to bear loads and exercise protocol tends to restore the default at control values in adult and older rats. The age factor only interfered in the stretching at the maximum limit, inducing a reduction of this property in the post-immobilization. Level of Evidence II, Investigating the Results of Treatment.

Propriedades mecânicas do músculo de ratos adultos e idosos, exercitado pós-imobilização / Muscle mechanical properties of adult and older rats submitted to exercise after immobilization

OBJETIVOS: Descrever os efeitos da imobilização, da remobilização livre e por meio de exercício físico sobre as propriedades mecânicas do músculo esquelético de ratos de duas faixas etárias. MÉTODOS: 56 ratos Wistar divididos em dois grupos etários, um grupo adulto (cinco meses) e um idoso (15 meses). Estes foram subdivididos em: controle, imobilizado, remobilizado livre e remobilizado por meio de exercício físico. Os membros posteriores dos ratos foram imobilizados por período de sete dias. O protocolo de exercícios foi composto por cinco sessões de natação, uma vez por dia e 25 minutos por sessão. O músculo gastrocnêmio foi submetido a ensaios de tração, sendo avaliadas as propriedades: carga (CLM), alongamento no limite máximo (ALM) e rigidez. RESULTADOS: A imobilização reduziu os valores de CLM e os protocolos de remobilização não foram suficientes para restabelecer aos níveis controle tanto nos animais adultos como nos idosos. O ALM apresentou diferença somente no grupo idoso. CONCLUSÕES: A imobilização reduz a capacidade do músculo de suportar cargas e protocolo de exercício físico apresenta uma tendência a restabelecer os valores ao padrão controle, tanto nos animais adultos como nos idosos. O fator idade interferiu somente no ALM gerando redução desta propriedade no período pós-imobilização. Nível de Evidência II, Investigação dos Resultados do Tratamento.

OBJECTIVES: To describe the effects of immobilization, free remobilization and remobilization by physical exercise about mechanical properties of skeletal muscle rats of two age groups. METHODS: 56 Wistar rats divided into two groups according to age, an adult group (five months) and an older group (15 months). These groups were subdivided in: control, immobilized, free remobilized and remobilized by physical exercise. The pelvic limb of rats was immobilized for seven days. The exercise protocol consisted by five swimming sessions, once per day and 25 minutes per session. The gastrocnemius muscle was subjected to tensile tests, and evaluated the properties: load at the maximum limit, stretching at the maximum limit and stiffness. RESULTS: The immobilization reduced the values of load at the maximum limit and the remobilization protocols were not sufficient to restore control levels in adult group and older rats. The stretching at the maximum limit differs only in the older group. CONCLUSIONS: The immobilization reduces the muscle's ability to bear loads and exercise protocol tends to restore the default at control values in adult and older rats. The age factor only interfered in the stretching at the maximum limit, inducing a reduction this property in the post-immobilization. Level of Evidence II, Investigating the Results of Treatment.