Efeitos da laserterapia de baixa potência associada ou não a exercício excêntrico no tratamento de tendinopatia induzida do tendão calcanear comum de Ratos (Rattus norvegicus)

• Autor(a) principal: Silva, Micheline Ozana da
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5189
• topic: Exercícios físicos; Tendinopatia; Terapia a laser; Rattus norvegicus; Physical exercise; Tendinopathy; Laser therapy; Rattus norvegicus; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA

This dissertation was carried out in two subprojects, with the first being entitled Clinical and biomechanical analyzes of the common calcaneal tendon of Wistar rats underwent laser therapy associate or not to eccentric exercise , and the second Histomorphometric analysis of the common calcaneal tendon of Wistar rats treated with laser therapy and eccentric exercise . The first subproject aimed to evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking) on tendinopathy of the common calcaneal tendon of Wistar rats, by clinical and biomechanical analyzes, while the second subproject, by means of histopathological and morphometrical analyzes. Sixty-three adult male rats were randomly distributed into the following groups: L (laser), E (eccentric exercise), LE (laser and eccentric exercise), R (rest), CT (contralateral tendon) and H (healthy tendon). The last two groups were present only in the first subproject. Unilateral tendinopathy with induced lesion was done by transversal compression followed by scarification of the tendon fibers, except in animals of group H. The treatments laser therapy (904 nm/3 J/cm2) and, or eccentric exercise (downhill walking; 12 m/min; 50 min/day; 15o inclination treadmill) began 24 h after surgery and remained for 20 days. The animals were submitted to physical evaluation (painful sensitivity and locomotion capacity examination) every three days, with euthanasia performed 3, 7, 14, and 21 days after lesion induction, except in the animals submitted to clinical and biomechanical analyzes, with this procedure being conducted only on day 21. During euthanasia, a macroscopic evaluation of the lesion site was carried out and the transversal diameter of the tendon was measured (analayzed only the first subproject). Sequentially, 18 tendons (from 15 rats) were collected and frozen at -20oC until biomechanical test, on which the characteristics maximum load (N), stress at ultimate tension (MPa) and maximum extension (mm) were analyzed. For the histomorphometric analysis, the following characteristics were studied: hemorrhage, fibrinous tissue adhesions, epitendon thickening, organization and amount of collagen fibers and blood vessels, inflammatory infiltrate and fibroblasts, as well as collagens (type I and III) and connective tissue organization. Local edema was observed on the xi first 72 h postoperative, but no pain was detected under physical examination. The macroscopic evaluation performed in the first subproject rats showed no increase in the transversal diameter of the tendons, and no presence of fibrous adhesions. However, this last characteristic was observed in an animal in the rest group, and in another in the laser therapy group, during the one week evaluation in the second subproject. In clinical and biomechanical analyzes, the group submitted to the eccentric exercise presented the lowest (p=0.0000) locomotion capacity among the injured animals (including those in the rest group), while in second subproject, such result was presented by the group underwent to rest (p=0.0008). No difference occured between groups, even when considering healthy and collateral tendons, in the evaluated biomechanical characteristics maximum load (p=0.4379), stress at ultimate tension (p=0.4605) and maximum extension (p=0.3820). However, it was observed among injured tendon, that the LE group required greater load and strain to rupture. No difference was found among groups, or between times in the characteristics hemorrhage, formation of fibrinous adhesion, organization of collagen fibers and connective tissue organization. Considering the groups, regardless of time, it was observed that eccentric exercise caused epitendon thickening (p=0.0204), which was lower in the group submitted to laser therapy. Histological analysis showed difference (p=0.0032) in the number of inflammatory cells along time, being observed in greater amount only in exercised group. This result was confirmed by morphometric analysis, which demonstrated that there was significant interaction (group x time) in this caracteristic, where the eccentric exercise increased (p=0.0014) the inflammatory infiltrate over time (3 and 21 days), however, when associate with laser teraphy, there was reduction the inflammatory reaction. On the other hand, the combination of the treatments led to a greater angiogenesis in morphometric (p=0.0000) and histological (p=0.0006) analyzes, compared to the other groups, while the application of low-level laser alone reduced this characteristic along time. Animals kept at rest presented the lowest (p=0.0000) amount of fibroblasts in morphometric analysis. However, in the histological evaluation significant interaction (group x time) (p=0.0024) was observed. Greater amount fibroblast was observed in groups E, L and LE, the 7 th , 14 th and 21 st days, respectively. The animals who received laser and were exercised showed higher (p=0.0000) amount of collagen fibers along time. The use of low-level laser at the dose of 3 J and wavelength of 904 nm, associated to walking treadmill eccentric exercise began 24 h after surgically-induced tendinopathy in Wistar rats does not result in biomechanically xii tendon as resistant or elastic as a healthy tendon. On the other hand, the combination of treatments shows the advantage of increasing the amount of collagen fibers, reduce fibrinous adhesion and inflammatory infiltrate. However, the application of laser therapy alone is adequate for angiogenesis and tendon thickening prevention. Keywords: Achilles tendon; histomorphometrical and biomechanical analyzes of tendon, physical activity, therapy with laser.