Lígia Inez Silva

Effects of immobilization and remobilization on the ankle joint in Wistar rats

A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint.

Avaliação do exercício físico como fator de analgesia em um modelo experimental de ciatalgia

OBJECTIVE: To evaluate the efficacy of physical exercise (swimming and jumping), with and without overload, working in reducing the pain of rats undergone to an experimental model of sciatica. METHODS: 24 rats were divided into four groups: Placebo (GP), Swimming Group (NG) Swimming 10% Group (GN10) and Leap Group (GS). All groups were submitted to the experimental sciatica model and assessed for pain post-exercise for the Functional Disability Test and the Von Frey filament. RESULTS: In comparison within groups there were significant differences in the moments after injury with the pre-injury, for both assessment instruments. With Von Frey filament was observed a significant difference in group GN10 and GS in the final moments of evaluation. In comparisons between groups were not statistically significant differences obtained with any assessment instrument. CONCLUSION: Treatment with physical exercise was not effective in reducing pain in rats subjected to experimental sciatica model.

A influência da crioterapia na dor e edema induzidos por sinovite experimental

O objetivo deste estudo foi analisar a influencia da crioterapia na dor e edema advindos de sinovite induzida em ratos. Foram utilizados 12 ratos, distribuidos em dois grupos: Controle (GC) - submetido a inducao de sinovite no joelho direito, e nao tratado; e Tratamento (GT) - submetido a sinovite no joelho direito, e tratado com crioterapia. Para induzir a lesao, foi injetado no espaco tibio-femoral formalina 5%. Para avaliacao da dor foi utilizado o teste de incapacidade funcional, que avaliou a dor durante a marcha do animal (tempo de elevacao da pata - TEP); e para quantificar o edema foi utilizado um paquimetro metalico, na regiao da interlinha do joelho. As avaliacoes ocorreram antes da injecao de formalina (AV1), 1 (AV2) e 2 horas (AV3) apos. Apos 10 minutos da lesao, o membro posterior direito foi submerso em agua com gelo, a 5oC por 20 minutos. A avaliacao do TEP mostrou aumento de 194,03% (AV2) e 169,26% (AV3) para GC; e 134,25% (AV2) e 103,13% (AV3) para GT, com relacao a AV1. Na comparacao entre os grupos, em AV3, houve diminuicao significativa para GT. A avaliacao do edema mostrou aumento do diâmetro, para GC de 39,15% (AV2) e 42,39% (AV3); e 27,91% (AV2) e 14,50% (AV3) para GT, tendo como referencia AV1; sendo que apenas GT apresentou diminuicao significativa entre AV2 e AV3. Conclui-se que os efeitos em curto prazo, da crioterapia, foram significativos para reduzir a dor e edema, em ratos submetidos a inducao de sinovite.

Treinamento aeróbico prévio à compressão nervosa: análise da morfometria muscular de ratos

INTRODUCTION: Sciatica stems from compression of the sciatic nerve and results in pain, paresthesia, decreased muscle strength and hypertrophy. Exercise is recognized in the prevention and rehabilitation of injuries, but when performed in overload, it may increase the risk of injury and subsequent functional deficit. OBJECTIVE: To evaluate effects of aerobic training prior to an experimental model of sciatic pain concerning morphometric parameters of soleus muscles of rats. MATERIALS AND METHODS: 18 rats were divided into three groups: sham (dip, 30 seconds), regular exercise (swimming, 10 minutes daily) and progressive aerobic training (swimming, progressive time from 10 to 60 minutes daily). After six weeks of exercise, rats were subjected to the experimental model of sciatic pain. On the third day after injury, they were killed and their soleus muscles were dissected, weighed and processed for histological analysis. The analyzed variables were: muscle weight, cross-sectional muscle area and mean diameter of muscle fibers. RESULTS: Statistically significant difference was observed for all groups when compared to control muscle and that submitted to sciatic injury. Intergroup analysis showed no statistically significant difference for any of the variables. CONCLUSION: Both regular physical exercise and aerobic training had no preventive or aggravating effects on the consequences of functional inactivity after sciatica.

Avaliação do papel de opioides endógenos na analgesia do laser de baixa potência, 820 nm, em joelho de ratos Wistar

BACKGROUND AND OBJECTIVES: Pain may result in incapacity when it is associated to structural injury. Low power laser is useful in therapies aiming at decreasing joint pain and at tissue repair, but it is still somewhat controversial. This study aimed at evaluating whether analgesia induced by 820 nm low power laser is affected by the application of an endogenous opioids inhibitor. METHOD: Twenty-four Wistar rats submitted to hyperalgesia were divided into four groups. G1: untreated; G2: treated with 820 nm laser; G3: naloxone injection before injury and untreated; G4: naloxone and treated with 820 nm laser. To induce hyperalgesia, 100 µL of 5% formalin were injected in the right tibiofemoral joint space. Nociception was evaluated by the time for flinching (TFF) in five moments: AV1 (pre-injury), AV2 (15 min/after), AV3 (30 min/after), AV4 (1 hour after) and AV5 (2 hours after). RESULTS: All groups showed significant difference between AV1 and AV2, but only G2 showed no difference between AV1 and AV3. There have been no differences for remaining moments as compared to AV1. CONCLUSION: Low power 820 nm laser analgesia is affected by naloxone.

Uso do exercício resistido antagonizado por naloxone como fator de analgesia em sinovite aguda de joelho de ratos Wistar

Analgesia arising from exercising can occur via release of endogenous opioids in the central nervous system and periphery. However, the literature remains controversial about exercise ways and actions in pain. Thus, the aim of this study was to evaluate whether resistance exercise produces changes on the nociception and suffers interference by applying an opioid inhibitor. 18 rats divided into three groups were used: G1 - hyperalgesia on right knee and untreated; G2 - hyperalgesia and treated with jumps in water; G3 - hyperalgesia with previous injection of naloxone and subsequent jumps. To produce hyperalgesia,100 ul of 5% formalin was injected in the tibiofemoral joint space. Pain was assessed using a digital von Frey filament on the right medial tibiofemoral joint. The evaluation periods were: pre-injury (EV1) after 15 minutes (EV2) and 30 minutes (EV3) and one hour (EV4). The applied exercise was jumping in water and it occurred after EV2. The animal performed 4 sets of 5 jumps, with an interval of 3 minutes and overload of 50% of body weight. In G1, nociceptive increase was observed, with significant decrease and return to initial baseline values in AV4; G2 showed threshold restoration after exercise and return to baseline; G3 reduced thresholds, without restoration or significant increase in them. We concluded that there was analgesia with use of exercise and that it was altered by blocking beta-endorphin.

Exercício resistido em meio aquático para ratos Wistar submetidos a trauma em tendão: avaliação da nocicepção e edema

BACKGROUND AND OBJECTIVES: Models of physical exercise for animals are useful tools to analyze organic functions difficult to be observed in humans, such as the evolution of pain after tendinous trauma. This study aimed at comparing the effects of resistance physical exercise on pain and edema in calcaneal tendons of rats submitted to trauma. METHOD: We used 18 Wistar rats divided in 3 groups: Control Group (CG, n = 6) - animals submitted to right calcaneal tendon trauma and untreated; Group 2 Jump (G2, n = 6) - animals submitted to trauma and treated with jumps in water, 2 series of 5 jumps; Group 3 Jump (G3, n = 6) - animals submitted to trauma and treated with jumps in water, 4 series of 5 jumps. To induce tendinous trauma, animals were anesthetized and received trauma with approximately 0.40 J in the lateral face of the calcaneal tendon. Jumps were performed daily with 24-hour intervals between applications. Digital Von Frey filament was used to assess pain and edema was assessed by tendon diameter variation with a caliper rule. RESULTS: Results have shown a slight advantage for G2, which has performed less repetitions of the exercise; for edema, however, there has been slight advantage for G3. CONCLUSION: Physical exercise has been slightly beneficial to decrease edema and pain.

Avaliação de parâmetros histomorfométricos em sóleos de ratos submetidos à remobilização por salto em meio aquático

INTRODUCTION: The muscular tissue is able to respond stimuli such as immobilization that induces hypotrophy altering muscle performance and are important methods that aim to reverse these deleterious effects in the post-immobilization. OBJECTIVE: The aim of this study was to evaluate transverse and longitudinal histomorphometric parameters of the soleus muscle fibers of rats immobilized in the shortened position and submitted to remobilization by jumping in water. METHODS: It was used 24 rats divided into 3 groups: G1 - remobilized freely, G2 - remobilized with jumps daily, and G3 - jumps on alternate days. The immobilization and remobilization occurred in 2 weeks for the right limb. The variables analyzed were: muscle mass, muscle fiber diameter, length and series sarcomeres estimate along the muscle. RESULTS: There was a reduction in muscle mass for both groups, to the diameter there was difference in G1 and G3, to the muscle length no significant differences, however, for the series sarcomeres estimate was found significant changes in all the groups. CONCLUSION: The protocol used has partial action against the deleterious effects of immobilization.

Effects of Low-Level Laser Therapy, 660 nm, in Experimental Septic Arthritis

The effectiveness of low-level laser therapy (LLLT) in the presence of an infectious process has not been well elucidated. The aim of the study was to evaluate the effects of LLLT in an experimental model of septic arthritis. Methods. Twenty-one Wistar rats were divided as follows: control group, no bacteria; placebo group, bacteria were inoculated; Treated group, bacteria were injected and treatment with LLLTwas performed. To assess nociception, a von Frey digital analgesimeter was applied. Synovial fluid was streaked to analyze bacterial growth. The standard strain of S. aureus was inoculated in the right knee. LLLT was performed with 660 nm, 2 J/cm2, over 10 days. After treatment, the knees were fixed and processed for morphological analysis by light microscopy. Results. It was found that nociception increases in the right knee. There was a lack of results for the seeding of the synovial fluid. The morphological analysis showed slight recovery areas in the articular cartilage and synovia; however, there was the maintenance of the inflammatory infiltrate. Conclusion. The parameters used were not effective in the nociception reduction, even with the slight tissue recovery due to the maintenance of inflammatory infiltrate, but produced no change in the natural history of resolution of the infectious process.

Avaliação de sóleos de ratas Wistar ooforectomizadas e remobilizadas em meio aquático

INTRODUCCION: a la incertidumbre sobre la manera mas eficaz de removilizacion de los musculos despues de periodos de inmovilizacion.OBJETIVO: Evaluar el comportamiento de removilizacion con natacion sobre parametros histomorfometricos del musculo soleo de ratas ooforectomizadas y pseudo ooforectomizadas.METODOS: Se utilizaron 24 ratas Wistar subdivididas en cuatro grupos: G1: sometidas a ooforectomia, inmovilizacion por 15 dias y removilizadas libremente; G2: ooforectomia, inmovilizacion y removilizadas con natacion por 10 dias; G3: pseudo ooforectomia, inmovilizacion y removilizadas libremente; G4: pseudo ooforectomia, inmovilizacion y removilizadas con natacion. Los musculos soleos derechos e izquierdos fueron disecados para analisis histomorfometricos longitudinal y transversal. El recuento de los sarcomeros se hizo en 300 micras y la longitud de la fibra muscular fue medida por paquimetro analogico. El peso muscular fue obtenido en balanza analitica y el diametro se realizo en 100 fibras por musculo.RESULTADOS: Hubo reduccion significativa tanto en el analisis longitudinal como en el transversal cuando se compararon los musculos soleos derechos e izquierdos de ambos grupos.CONCLUSION: La inmovilizacion del musculo soleo de ratas ooforectomizadas y pseudo ooforectomizadas causa efectos nocivos para la morfometria muscular y la removilizacion por medio de la natacion no fue capaz de promover el retorno de los patrones estructurales del musculo soleo.