ABSTRACT
Distúrbios decorrentes da artrite reumatoide (AR) resultam em incapacitação funcional, com reflexos econômicos e sociais aos sistemas de saúde. Uma alternativa terapêutica que tem sido proposta é a atividade física na modalidade resistida. O presente estudo analisou os efeitos do exercício resistido de subida em escada (ERSE) na histomorfologia do músculo extensor longo dos dedos (EDL) de ratos Wistar, em modelo experimental de AR. Ratos machos (n=20) foram distribuídos aleatoriamente em quatro grupos. A lesão da AR foi induzida por administração intra-articular de Adjuvante Completo de Freund (CFA). Os resultados revelaram que a AR alterou a histomorfometria das fibras do EDL e que o ERSE promoveu reparo muscular, sugerindo sua eficiência na restauração da funcionalidade muscular. Ainda, o ERSE pode ser uma opção de tratamento voltado à melhoria na qualidade de vida dos portadores de AR.
Disorders from rheumatoid arthritis (RA) result in functional disability, with economic and social impacts on health systems. A therapeutic alternative that has been proposed is physical activity in the resisted modality. Current study analyzed the effects of resistance exercise on stairs (ERSE) on the histomorphology of the extensor digitorum longus muscle (EDL) of Wistar rats in an experimental model of RA. Male rats (n=20) were randomly assigned to four groups. RA injury was induced by intra-articular administration of Freund's Complete Adjuvant (CFA). Results revealed that RA altered the histomorphometry of EDL fibers and that ERSE promoted muscle repair, suggesting its efficiency in restoring muscle functionality. Furthermore, ERSE may be a treatment option to improve the life quality of people with RA.
ABSTRACT
ABSTRACT This study aimed to investigate the effects of low-level laser therapy (LLLT) on muscle repair in rats with chronic alcohol intake. Thirty male Wistar rats were distributed into three groups: injured tibialis anterior (TA) muscle without treatment (IC); chronic ingestion of alcohol plus injured TA muscle (AI); and chronic ingestion of alcohol plus injured TA plus LLLT (AIL). Each group was divided into two different subgroups, and rats were sacrificed on days 3 and 7 post-injury. Morphological features in the injured areas were similar with or without alcohol intake (IC and AI); however, LLLT promoted a decrease in the number of inflammatory cells and destroyed zones, as well as improved tissue organization (AIL). In general, alcohol intake caused a decrease in myogenic regulatory factors (MyoD and myogenin) and vascular endothelial growth factor in the AI group. Moreover, LLLT promoted recovery of these factors to the same level as in animals without alcohol intake (IC and AIL). LLLT was able to increase the expression of myogenic and vascular growth factors and stimulate skeletal muscle regeneration in rats with chronic alcohol intake.
ABSTRACT
Summary The skeletal muscle tissue has a remarkable ability to alter its plastic structural and functional properties after a harmful stimulus, regulating the expression of proteins in complex events such as muscle regeneration. In this context, considering that potential therapeutic agents have been widely studied, nutritional strategies have been investigated in order to improve the regenerative capacity of skeletal muscle. There is evidence of the modulatory action of fatty acids, such that oleic and linoleic acids, that are abundant in Western diets, on muscle function and trophism. Thus, fatty acids appear to be potential candidates to promote or impair the recovery of muscle mass and function during regeneration, since they modulate intracellular pathways that regulate myogenesis. This study is the first to describe and discuss the effect of fatty acids on muscle plasticity and trophism, with emphasis on skeletal muscle regeneration and in vitro differentiation of muscle cells.
Resumo O tecido muscular esquelético possui a notável capacidade plástica de alterar suas propriedades estruturais e funcionais após um estímulo lesivo, regulando a expressão de proteínas durante eventos complexos como a regeneração muscular. Nesse contexto, considerando que possíveis agentes terapêuticos vêm sendo amplamente estudados, estratégias nutricionais têm sido investigadas na perspectiva de melhorar a capacidade regenerativa do músculo esquelético. Há evidências da ação modulatória dos ácidos graxos, como os ácidos oleico e linoleico, que são abundantes nas dietas ocidentais, sobre a função muscular e o trofismo. Nesse sentido, os ácidos graxos parecem ser potenciais candidatos para promover ou prejudicar a recuperação da massa e a função muscular durante a regeneração, uma vez que modulam vias intracelulares reguladoras da miogênese. Este trabalho é o primeiro a descrever e discutir o efeito dos ácidos graxos sobre a plasticidade e o trofismo muscular, com ênfase na regeneração do músculo esquelético e na diferenciação de células musculares in vitro.
Subject(s)
Humans , Regeneration/physiology , Muscle, Skeletal/physiology , Fatty Acids/metabolism , Cell Differentiation/drug effects , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Muscle Fibers, Skeletal/cytology , Muscle Fibers, Skeletal/metabolism , Myoblasts, Skeletal/cytologyABSTRACT
Objective To observe the effect of the electroacupuncture ( EA) on the expression of cyclin-de-pendent kinase 5 ( Cdk5 ) in rats with muscle contusion and to explore its mechanism. Methods Thirty-two Sprague-Dawley rats were randomly divided into a normal group of 4, a model group of 4, a natural recovery group ( NR) of 12 and an EA group of 12. All except those in the normal group had acute skeletal muscle contusion induced through a heavy blow. The EA group was treated with 15 minutes of EA daily beginning 48 h after the injury while the other rats received no EA. The model group was sacrificed 24 h after modeling, and rats from the NR and EA groups were sacrificed on the 7th, 14th and 21st day after the modeling to collect tissues. Hematoxylin eosin ( HE) staining, Western blotting and quantitative real-time fluorescence PCR were used to observe any histological changes, as well as Cdk5 protein and mRNA expression. Results The HE staining showed that the other 3 groups displayed larger a-mounts of muscle fiber fracture, dissolution and inflammatory cell invasion than was observed in the normal group. Compared with the NR group, quicker recovery was seen in the EA group as evidenced by faster muscle satellite cell proliferation and more new muscle fiber generation. The average Cdk5 protein expression in both the NR and EA groups was higher than in the normal group, and that of the EA group was significantly lower than that of the NR group. Conclusions Muscle contusion can increase Cdk5 expression in skeletal muscles, at least in rats. EA can promote the restoration of skeletal muscle function, probably by inhibiting CDK5 protein and mRNA expression.
ABSTRACT
BACKGROUND: Macrophages play a major role among the inflammatory cells that invade muscle tissue following an injury. Low-level laser therapy (LLLT) has long been used in clinical practice to accelerate the muscle repair process. However, little is known regarding its effect on macrophages. OBJECTIVE: This study evaluated the effect of LLLT on the mitochondrial activity (MA) of macrophages. METHOD: J774 macrophages were treated with lipopolysaccharide (LPS) and interferon - gamma (IFN-γ) (activation) for 24 h to simulate an inflammatory process, then irradiated with LLLT using two sets of parameters (780 nm; 70 mW; 3 J/cm2 and 660 nm; 15 mW; 7.5 J/cm2). Non-activated/non-irradiated cells composed the control group. MA was evaluated by the cell mitochondrial activity (MTT) assay (after 1, 3 and 5 days) in three independent experiments. The data were analyzed statistically. RESULTS: After 1 day of culture, activated and 780 nm irradiated macrophages showed lower MA than activated macrophages, but activated and 660 nm irradiated macrophages showed MA similar to activated cells. After 3 days, activated and irradiated (660 nm and 780 nm) macrophages showed greater MA than activated macrophages, and after 5 days, the activated and irradiated (660 nm and 780 nm) macrophages showed similar MA to the activated macrophages. CONCLUSIONS: These results show that 660 nm and 780 nm LLLT can modulate the cellular activation status of macrophages in inflammation, highlighting the importance of this resource and of the correct determination of its parameters in the repair process of skeletal muscle. .
CONTEXTUALIZAÇÃO: O macrófago tem papel de destaque dentre as células inflamatórias que invadem o músculo após as lesões. Por outro lado, o laser em baixa intensidade (LBI) tem sido muito utilizado na clínica para acelerar o reparo muscular, e pouco se conhece sobre seu efeito nos macrófagos. OBJETIVO: Avaliar o efeito do LBI sobre a atividade mitocondrial (AM) de macrófagos ativados para simular um processo inflamatório. MÉTODO: Macrófagos J774 foram tratados com lipopolissacarídeo (LPS) e IFN-gamma (ativação) por 24 horas para simular um processo inflamatório e então foram irradiados com LBI (780 nm; 70 mW; 3 J/cm(2) e 660 nm; 15mW; 7,5 J/cm(2)). A AM foi avaliada pela técnica MTT após um, três e cinco dias das irradiações. Foram realizados três experimentos independentes, e os dados, submetidos à análise estatística. RESULTADOS: Após um dia de cultivo, os macrófagos ativados e irradiados com o laser de 780 nm mostraram AM menor que os somente ativados, já os macrófagos ativados e irradiados com o laser de 660 mostraram AM semelhante aos somente ativados. Após três dias, os macrófagos ativados e irradiados (660 e 780 nm) mostraram AM maior que os macrófagos ativados; já após cinco dias, os grupos ativados e irradiados (660 e 780 nm) mostraram AM semelhante aos macrófagos somente ativados. CONCLUSÕES: Esses resultados mostram que tanto o LBI de 660 nm como o de 780 nm são capazes de modular a ativação celular de macrófagos em situação de inflamação, ressaltando a importância desse recurso e da determinação de seus parâmetros dosimétricos no processo de reparo do músculo esquelético. .
Subject(s)
Low-Level Light Therapy , Macrophages/metabolism , Macrophages/radiation effects , Mitochondria/radiation effects , Cells, CulturedABSTRACT
The main purpose of the present study was to investigate the effects of low-level laser therapy (LLLT) used in two different fluencies on injured skeletal muscle after cryolesion by means of histopathological analysis and immunohistochemistry for COX-2. A total of sixty male Wistar rats were randomly distributed into three groups: injured animals without any treatment; 808 nm laser treated group, at 10 J/cm² and 808 nm laser treated group, at 50 J/cm². Each group was divided into two different subgroups (n=10) on days 6 and 13 post-injury. The results showed that the animals irradiated with laser at 10 J/cm² or 50 J/cm² presented the areas with cell infiltrate and pointed out to minor and mild areas with destroyed zones compared with the control group. Also, a COX-2 downregulation was noticed in the groups exposed to laser at two fluences evaluated in this study. Significant statistically differences (p<0.05) were noticed to collagen deposition in the laser treated animals, with the fluence of 50 J/cm² when compared to the other groups on day 13 post-surgery. Taken together, these results suggested that laser therapy could have positive effects on muscle repair in the rats after cryolesion.