EFEITOS DA VIBRAÇÃO MECÂNICA SOBRE O NERVO ISQUIÁTICO DE RATAS WISTAR OOFORECTOMIZADAS, SOBRE A NOCICEPÇÃO E PARÂMETROS HISTOMORFOMÉTRICOS

O uso da plataforma vibratória vem sendo amplamente estudado, principalmente como forma de tratamento para osteoporose, porém este estímulo pode causar alteração da morfologia do nervo periférico e diminuição do limiar nociceptivo, além de provocar mais alterações se o período de aplicação for maior. Essas lesões nervosas decorrentes da vibração são comumente conhecidas no âmbito ocupacional, porém não exploradas em parâmetros utilizados na pratica terapêutica, visto que esta normalmente associa a vibração com outros fatores de risco para o desenvolvimento de lesão, como a diminuição do estrogênio que ocorre na mulher no período pós-menopausa, sendo uma das causas da osteoporose, esta diminuição pode ser simulada por meio da ooforectomia em ratas. Assim, torna-se relevante a realização de estudos que avaliem o efeito da vibração sobre o nervo periférico, durante diferentes períodos, em um protocolo de tratamento de osteoporose pós menopausa. Ressaltando o objetivo deste estudo, que é analisar e comparar, os efeitos nociceptivos e parâmetros histomofométricos da vibração mecânica de corpo inteiro sobre o nervo isquiático durante quatro e oito semanas em ratas ooforectomizadas. Foram utilizadas 64 ratas Wistar com 8 semanas de idade, randomizadas nos grupos Pseudooforectomia (GP) e Ooforectomia (GO), subdivididos em oito subgrupos: animais que não realizaram nenhum tratamento e eutanasiados após 4 (GP4, GO4) e 8 (GP8, GO8) semanas, animais tratados durante 4 (GPT4, GOT4) e 8 (GPT8, GOT8) semanas. Realizou-se tratamento com vibração, com frequência de 60Hz, por 10 minutos, três dias por semana, totalizando quatro e oito semanas. A avaliação da nocicepção foi realizada na face plantar do membro pélvico direito, prévio ao procedimento cirúrgico, no início e final de quatro e oito semanas de tratamento, por meio de um analgesímetro digital, tipo filamento de Von Frey. Após o período experimental, os animais foram eutanasiados e o nervo isquiático processado para análises histomorfométrica em microscopia de luz. As imagens foram mensuradas no programa Image Pro Plus 6.0. Para variável de nocicepção e morfometria do nervo isquiático, independente da ooforectomia e do tempo de tratamento, não houve diferenças significativas (p<0,05). Assim, se conclui que a vibração mecânica de corpo inteiro, não promoveu alteração no limiar nociceptivo e na histomorfometria do nervo isquiático de ratas Wistar nos parâmetros utilizados no estudo

Análise da corrente interferencial associada ao alongamento na extensibilidade de isquiotibiais

ABSTRACT Analysis of interferential current associated with stretching in the extensibility of ischiotibialsIntroduction: The muscle shortening can decrease tissue extensibility and increase the risk of injury. Interferential current (IC) can alter nerve conduction, in addition to stimulating the central mechanisms of analgesia. The aim of this study was to analyze the effect of IC on hamstring muscles extensibility in healthy individuals. Methods: Twenty subjects with hamstrings muscle shortening, were randomly divided into 2 groups: placebo and interferential. The subjects received the application IC, or placebo, bipolar, 4 KHz, for 15 minutes during 3 days and then were subjected to the active static stretching protocol. To evaluate the flexibility of the posterior chain it was used the standard test bench sit and reach (Wells bench) and muscle extensibility hamstrings goniometric plank. The evaluations were performed five times for both groups. Results: There were no significant differences in the assessment with the Wells bench, already for goniometric plank were differences between the evaluations, but not between the groups. Conclusion: The application of interferential current, bipolar, 4 KHz, was not effective in increasing the extensibility of the hamstring muscles.Introdução: O encurtamento muscular pode diminuir a extensibilidade tecidual e aumentar o risco de lesões. A corrente interferencial (CI) é capaz de alterar a condução nervosa, além de estimular os mecanismos centrais de analgesia. O objetivo deste estudo foi analisar o efeito da CI na extensibilidade dos músculos isquiotibiais em indivíduos saudáveis. Métodos: Vinte indivíduos, com encurtamento muscular de isquiotibiais, foram distribuídos aleatoriamente em 2 grupos: placebo e interferencial. Os indivíduos receberam a aplicação de CI, ou placebo, bipolar, de 4KHz, durante 15 minutos, por 3 dias, e em seguida foram submetidos ao protocolo de alongamento estático ativo. Para avaliação da flexibilidade da cadeia posterior foi utilizado o banco padrão de testes sentar e alcançar (banco de Wells) e para extensibilidade muscular de isquiotibiais a prancha goniométrica. As avaliações foram realizadas 5 vezes para ambos os grupos. Resultados: Não houve diferenças significativas para as avaliações com o banco de Wells, já para a prancha goniométrica houve diferenças entre as avaliações, mas, não entre os grupos. Conclusão: A aplicação de corrente interferencial, bipolar, de 4 KHz, seguida de alongamento não se mostrou eficaz em aumentar a extensibilidade dos músculos isquiotibiais.

Morphology of extensor digitorum longus of Wistar rats after remobilization by vibratory platform

Introduction. In exercise, vibrations are performed in order to produce rapid and short changes in muscle length. These changes are detected by sensory receptors, in response try to dampen the vibratory waves through a modulation of muscle stiffness. However, its effects on the morphology of muscle tissue are still not fully established, especially after long periods of immobilization. Aim. To compare the effects of the vibratory platform on the remobilization of the extensor digitorum longus (EDL) muscle of Wistar rats with free remobilization. Material and methods. 20 rats were divided into: CG (Control), IG (immobilized), IFG (immobilization and free remobilization), IPG (immobilization and remobilization with vibratory platform). The immobilization was performed on the pelvic limb for 15 days. The remobilization with vibratory platform was done for 10 minutes daily, for 2 weeks. The EDL was processed for histological analysis of cross-sections. Results. The area, larger diameter, smaller diameter and fiber density of the EDL muscle of GI presented significant alteration when opposed to CG, IFG and IPG. The density of nuclei of the EDL muscle of IG presented a significant increase when opposed to the others, and IPG also presented a significant increase when compared to CG. Conclusion. The morphology and morphometry of the EDL muscle tissue were affected, and both free and vibration platform remobilization re-established the morphological aspects of the muscle fiber, without significant differences between the methods

Morphological and nociceptive effects of mechanical vibration on the sciatic nerve of oophorectomized Wistar rats

Abstract Aim: To evaluate the effects of whole-body vibration in the sciatic nerve of oophorectomized Wistar rats, on nociceptive and morphological parameters, such as fiber, axon, and myelin sheath diameters, G ratio, number of nerve fiber and nuclei of Schwann cells, and percentage of connective tissue. Method: Sixty-four rats were used in the groups sham-operate and oophorectomy (n = 32/group); after surgical procedures, each group was subdivided into four: euthanized in the 12th week, untreated and treated for four weeks; and euthanized in the 16th week, untreated and treated for eight weeks. The treatment with vibration was performed with a 60 Hz frequencies, for 10 minutes, three days a week, with duration of 4 or 8 weeks. Nociception was evaluated later, in the right paw, by means of a digital analgesimeter, prior to surgery, at the beginning and at the end of the protocol. After the trial period, the sciatic nerve was dissected for examination of the general morphology of the tissue and morphometric analysis; later, the animals were euthanized. Results: Regarding nociception and the morphometry of the sciatic nerve, independent of oophorectomy and treatment time, there was no statistically significant difference within and between groups. Also, the general morphology of the tissue in all groups had characteristics that were preserved. Conclusion: The mechanical vibration did not alter the nociceptive threshold and the morphological aspects of nerve fibers in oophorectomized Wistar rats

Histological aspects of whole-body vibration in the knee remobilization of Wistar rats

Introduction and aim. The knee is one of the joints where immobilization is most used, however, it can cause morphological changes in the joint tissues and is a challenge to be overcome during rehabilitation. Whole-body vibration (WBV) is capable of generating repetitive oscillatory movements, which cause mechanical stimuli that interfere with tissue plasticity. The aim of this study was to analyze the knee morphology of Wistar rats submitted to remobilization with WBV. Material and methods. 32 male rats were used, divided into four groups (n=8): Control Group (G1), Immobilization Group (G2), Immobilized Group and Free Remobilization (G3), Remobilized Group with WBV (G4). For immobilization, a plastered apparatus was used for 15 days. G3 and G4 carried out free remobilization or with WBV, respectively, for 2 weeks. The knee joints were processed for light microscopy. Results. The WBV led to a reduction in the inflammatory infiltrate in the articular cavity and greater presence of adipocytes in the subintima of the synovial membrane. Conclusion. Remobilization with WBV induced a better tissue response in the synovial membrane when compared to free remobilization