Análises proteômicas do tendão calcâneo sob efeito do envelhecimento e treinamento de força

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ceilândia, Programa de Pós-graduação em Ciências e Tecnologias em Saúde, 2015.O envelhecimento é descrito como um processo complexo, multifatorial, caracterizado pelo acúmulo de alterações deletérias nas células e tecidos, atuando negativamente na homeostase dos sistemas. Nessa perspectiva, o treinamento de força (TF) possui grande relevância clínica por se tratar de um mecanismo capaz de minimizar essas alterações inerentes ao envelhecimento. Porém, a base biológica e molecular desse contexto (envelhecimento e ações do treinamento de força - TF) no tecido tendíneo, ainda é pouco compreendida. Objetivo: identificar e caracterizar a distribuição das proteínas do tendão calcâneo (TC) de ratos e elucidar as suas funções para o melhor entendimento do processo de envelhecimento e do TF. Materiais e Métodos: foram utilizados 24 Rattus Wistar Novergicus Albinos, de 4 e 24 meses, divididos em quatro grupos experimentais: jovens (6), treinado jovem (6), senil (6) e treinado senil (6). O treinamento de força de 12 semanas foi realizado uma vez a cada dois dias. Primeiramente, os ratos foram adaptados ao protocolo de treinamento de força para escalarem uma escada vertical, com pesos presos as suas caudas, realizando de 8 a 12 movimentos por escalada. As sessões de treinamento consistiram de quatro escaladas na escada, com 65%, 85%, 95% e 100% da capacidade máxima de carregamento do rato, determinada na sessão anterior. Posteriormente, os TC foram retirados e analisados por meio da técnica proteômica LC-ESI-MS/MS. Resultados: foi identificado um total de 29 proteínas nos quatro grupos analisados. Do total, 12 foram comuns a mais de um grupo, e o restante (17 proteínas) foi classificado como diferencial em seus respectivos grupos. Sete dessas proteínas (COMP, COL1A1, COL1A2, CAIII, FAPB3, GSN, S100A6 e Tf) demonstraram níveis de intensidade diminuídos em função do envelhecimento; oito (COMP, COL1A1, DNAAF1, FAPB3, GSN, S100A6, ALB e Tf) tiveram regulações positivas com o protocolo de TF e, em duas (COMP e DNAAF1), foi possível observar a ação do TF diretamente no tendão senil. Conclusão: neste estudo, foi observada uma diminuição na intensidade de proteínas ligadas a diversos aspectos (estruturais e celulares) do tecido tendíneo com o envelhecimento e notificada a capacidade do TF em modular, positivamente, proteínas com baixos níveis durante a senilidade, sendo ainda mais efetivo na regulação proteica durante a jovialidade.Aging is described as a multifactorial complex process, characterized by the accumulation of deleterious alterations in cells and tissues, therefore, acting negatively in the systems homeostasis. In this perspective, strength training (ST) is of great clinical importance for elderly people since it is able to minimize these inherent age-related changes. However, the biological and molecular basis of such a context (aging and strength training actions - ST) in the tendon, is still poorly understood. Objectives: To identify and characterize the distribution of Achilles tendon (AT) proteins in rats as well as explain their functions for a better understanding of the aging process and ST. Materials and Methods: 24 Wistar novergicus albinos Rattus were used, aged 4 and 24 months, and divided into four experimental groups: young rats (6), young trained rats (6), senile rats (6) and senile trained rats (6). A 12-week ST was conducted once every two days. Initially, the rats were adapted to the strength training protocol, which required them to climb a vertical ladder with weights attached to their tails, making them perform from 8 to 12 movements per climb. The training sessions consisted of four ladder climbs with 65, 85, 95, and 100% of the rat’s maximal carrying capacity, as determined in the previous session. Afterwards, the AT were removed and analyzed by using the following proteomics technique LC-MS / MS. Results: a total of 29 proteins were identified in the four groups analyzed. Among them, 12 were common to more than one group, and 17 were classified as being divergent from their own groups. Seven of those proteins (COMP, COL1A1, COL1A2, CAIII, FAPB3, GSN, S100A6 and Tf) showed decreased intensity levels as a result of aging; eight of them (COMP, COL1A1, DNAAF1, FAPB3, GSN, S100A6, ALB and Tf) had positive settings with the ST protocol and, finally, in two of them (COMP and DNAAF1) was possible to observe the ST action right in the senile tendon. Conclusion: In this study, we demonstrated that both aging and ST cause proteomic changes in the AT. As expected, it was observed a decrease in the intensity of proteins related to different aspects (structural as well as cellular) of the tendon tissue as a consequence of aging. In addition, it was noticed the ST ability to positively modulate low-leveled proteins during senility, becoming even more effective in the regulation of protein levels during joviality

Pipkin Type-II Femoral Head Fracture: A Biomechanical Evaluation by the Finite-Element Method

Abstract Objective To evaluate the biomechanical capacity of two forms of fixation for Pipkin type-II fractures, describing the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used. Materials and Methods Two internal fasteners were developed to treat Pipkin type-II fractures through finite elements: a 3.5-mm cortical screw and a Herbert screw. Under the same conditions, the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used were evaluated. Results The vertical displacements evaluated were of 1.5mm and 0.5mm. The maximum principal stress values obtained in the upper region of the femoral neck were of 9.7 KPa and 1.3 Kpa, and the minimum principal stress values obtained in the lower region of the femoral neck were of-8.7 KPa and -9.3 KPa. Finally, the peak values for Von Mises stress were of 7.2 GPa and 2.0 GPa for the fixation models with the use of the 3.5-mm cortical screw and the Herbert screw respectively. Conclusion The fixation system with the Herbert screw generated the best results in terms of reduction of vertical displacement, distribution of the maximum principal stress, and the peak Von Mises equivalent stress, demonstrating mechanical superiority compared to that of the 3.5-mm cortical screw in the treatment of Pipkin type-II fractures

Calcaneal tendon plasticity following gastrocnemius muscle injury in rat

Cross-talk between skeletal muscle and tendon is important for tissue homeostasis. Whereas the skeletal muscle response to tendon injury has been well-studied, to the best of our knowledge the tendon response to skeletal muscle injury has been neglected. Thus, we investigated calcaneal tendon extracellular matrix (ECM) remodeling after gastrocnemius muscle injury using a rat model. Wistar rats were randomly divided into four groups: control group (C; animals that were not exposed to muscle injury) and harvested at different time points post gastrocnemius muscle injury (3, 14, and 28 days) for gene expression, morphological, and biomechanical analyses. At 3 days post injury, we observed mRNA-level dysregulation of signaling pathways associated with collagen I accompanied with disrupted biomechanical properties. At 14 days post injury, we found reduced collagen content histologically accompanied by invasion of blood vessels into the tendon proper and an abundance of peritendinous sheath cells. Finally, at 28 days post injury, there were signs of recovery at the gene expression level including upregulation of transcription factors related to ECM synthesis, remodeling, and repair. At this time point, tendons also presented with increased peritendinous sheath cells, decreased adipose cells, higher Young’s modulus, and lower strain to failure compared to the uninjured controls and all post injury time points. In summary, we demonstrate that the calcaneal tendon undergoes extensive ECM remodeling in response to gastrocnemius muscle injury leading to altered functional properties in a rat model. Tendon plasticity in response to skeletal muscle injury merits further investigation to understand its physiological relevance and potential clinical implications

Detraining and Anabolic-Androgenic Steroid Discontinuation Change Calcaneal Tendon Morphology

Several side effects of anabolic-androgenic steroid (AAS) administration associated with training are reported in the biomechanical properties of the calcaneal tendon (CT) of rats. Thus, the aim of the present study is to evaluate the effects of the detraining and discontinuation of AAS administration on the CT morphology of rats submitted to exercise in water. Animals were divided into two groups (20/group): (1) Immediately after training (IA), and (2) Six weeks of detraining and AAS discontinuation (6W). The IA group included four subgroups: Sedentary (S), Trained (T), Sedentary with AAS administration (SAAS), and trained with AAS administration (TAAS). The 6W group included four subgroups: Sedentary (6W-S), six weeks of detrained (6W-T), six weeks of sedentary with AAS discontinuation (6W-SAAS), and six weeks of detrained with AAS discontinuation (6W-TAAS). Data show significant reduction in adipose cells volume density (Vv%) in the distal CT in 6W-TAAS group, indicating that training can exert a positive effect on the tendon. The 6W-SAAS group exhibited increased adipose cells Vv% in the distal region, compared with the W6-S and W6-T groups. A decrease in tendon proper cells Vv% and in peritendinous sheath cells Vv% of proximal and distal regions was also observed. In 6W-TAAS group showed increase in adipose cells, blood vessels, peritendinous sheath cells, and tendon proper cells Vv% in the distal region of the CT. The vertical jumps in water were not able to protect CT regions from the negative effects of AAS discontinuation for six weeks. However, after detraining and AAS discontinuation, many protective factors of the mechanical load in the long-term could be observed

Early Neuromuscular Electrical Stimulation Preserves Muscle Size and Quality and Maintains Systemic Levels of Signaling Mediators of Muscle Growth and Inflammation in Patients with Traumatic Brain Injury: A Randomized Clinical Trial

Objective. To investigate the effects of an early neuromuscular electrical stimulation (NMES) protocol on muscle quality and size as well as signaling mediators of muscle growth and systemic inflammation in patients with traumatic brain injury (TBI). Design. Two-arm, single-blinded, parallel-group, randomized, controlled trial with a blinded assessment. Setting. Trauma intensive care unit at a university hospital. Participants. Forty consecutive patients on mechanical ventilation (MV) secondary to TBI were prospectively recruited within the first 24 hours following admission. Interventions. The intervention group (NMES; n = 20) received a daily session of NMES on the rectus femoris muscle for five consecutive days (55 min/each session). The control group (n = 20) received usual care. Main Outcome Measures. Muscle echogenicity and thickness were evaluated by ultrasonography. A daily blood sample was collected to assess circulating levels of insulin-like growth factor I (IGF-I), inflammatory cytokines, and matrix metalloproteinases (MMP). Results. Both groups were similar at baseline. A smaller change in muscle echogenicity and thickness (difference between Day 1 and Day 7) was found in the control group compared to the NMES group (29.9 ± 2.1 vs. 3.0 ± 1.2, p<0.001; −0.79 ± 0.12 vs. −0.01 ± 0.06, p<0.001, respectively). Circulating levels of IGF-I, pro-inflammatory cytokines (IFN-y), and MMP were similar between groups. Conclusion. An early NMES protocol can preserve muscle size and quality and maintain systemic levels of signaling mediators of muscle growth and inflammation in patients with TBI. This trial is registered with https://www.ensaiosclinicos.gov.br under number RBR-2db

Effects of Home-Based Electrical Stimulation on Plasma Cytokines Profile, Redox Biomarkers, and Metalloproteinases in the Heart Failure with Reduced Ejection Fraction: A Randomized Trial

Background: Low-frequency electrical stimulation (LFES) is an adjuvant method for heart failure (HF) patients with restrictions to start an exercise. However, the impact on molecular changes in circulating is unknown. We investigated the effects of 10 weeks of home-based LFES on plasma cytokines profile, redox biomarkers, metalloproteinases (MMPs) activity, and exercise performance in HF patients. Methods: Twenty-four HF patients (52.45 ± 9.15 years) with reduced ejection fraction (HFrEF) (EF 0.05). Conclusion: LFES protocol is a promising intervention to modulate MMPs activity in HFrEF patients, although with limited functional effects. These preliminary responses may help the muscle to adapt to future mechanical demands dynamically