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.

Evaluation of rats´ soleus muscle submitted to remobilization protocol with therapeutic ultrasound associated with static stretching

Despite the deleterious effects, immobilization, is still often used in the treatment of musculoskeletal disorders, even with the occurrence of muscular atrophy, its reversal is a major challenge to rehabilitation. The aim of this study was evaluate the tropism of rats soleus muscle submitted to remobilization with static stretching, preceded by ultrasound, thermal and non thermal. We used 28 rats divided into four groups: G1‑immobilized and remobilized with static stretching, G2-remobilized with stretching preceded by ultrasound 1.0 W.cm–²; G3 – ultrasound at 0.5 W.cm–² , G4 – ultrasound with 0.2 W.cm–². All animals were immobilized in plantarflexion, producing shortening of the right soleus muscle for 15 days. For the groups subjected to remobilization with ultrasound doses were used according to the group, for 3 minutes, for 10 days with an interval of 2 days after the 5th treatment. After treatment with ultrasound (or not for the G1), the animals were subjected to 3 sets of 30 seconds, with 30 seconds interval between them, of static stretching of the soleus. The soleus were dissected, weighed and processed for preparation of histological slides in cross section, and evaluated the smallest diameter of 100 fibers per muscle. There was significant reduction in weight between left and right muscles in all groups, for diameters G3 showed no difference. Conclusion: stretching with or without ultrasound, was unable to reverse the deleterious effects of immobilization on muscle weight, but in the mean dose there was protective effect on the diameter of the fibers.

Low-level laser therapy, at 830 nm, for pain reduction in experimental model of rats with sciatica / Laser de baixa potência, 830 nm, na redução da dor em ratos submetidos à modelo experimental de ciatalgia

Chronic pain, resulting from nerve compression, is a common clinical presentation. One means of conservative treatment is low-level laser therapy, although controversial. The aim of this study was to evaluate the effects of two doses of low-level laser, at 830 nm, on pain reduction in animals subjected to sciatica. Eighteen rats were used, divided into three groups: GS (n=6), sciatica and simulated treatment; G4J (n=6), sciatica and treatment with 4 J/cm²; and G8J (n=6), sciatica and irradiation with 8 J/cm². The right sciatic nerve was exposed and compressed using catgut thread. Five days of treatment were started on the third postoperative day. Pain was assessed by means of the paw elevation time during gait: before sciatica, before and after the first and second therapies, and the end of the fifth therapy. Low-level laser was effective in reducing the painful condition.

A dor crônica, resultante de compressão nervosa, é uma apresentação clínica frequente. Um dos meios de tratamento conservador, é o laser de baixa potência, apesar de controvérsias. O objetivo do estudo foi avaliar os efeitos de duas doses de laser de baixa potência, 830 nm, na redução da dor em animais submetidos à ciatalgia. Foram utilizados 18 ratos, divididos em 3 grupos: GS (n=6) ciatalgia e simulado o tratamento; G4J (n=6) ciatalgia e tratado com 4 J/cm², G8J (n=6) ciatalgia e irradiado com 8 J/cm². O nervo isquiático direito foi exposto e realizada a compressão com fio catgut. No 3º dia pós-operatório, iniciou-se o tratamento, durante 5 dias. Verificou-se a dor, por meio do tempo de elevação da pata, na marcha: anterior à ciatalgia, pré e pós 1ª e 2ª terapias, e ao final da 5ª terapia. O laser de baixa potência foi eficaz na redução do quadro álgico.