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Objective: To evaluate the effects of magnifying the damage caused by obesity induced by monosodium glutamate, using a model of maternal periodontitis, on the structure of the anterior tibialis muscle of the offspring., Materials and Methods: Twenty-four female Wistar rats were divided into four experimental groups: control (n = 6), obese (n = 6), control with periodontitis (n = 6) and obese with periodontitis (n = 6). At 78 days of life, the rats were mated with males without any experimental intervention. The offspring of these rats (n = 1/L), at 120 days of life, were weighed and measured, then euthanized. Plasma was collected for analysis of cytokines IL-6, IL-10, IL-17 and TNF-α. Adipose tissues were collected and weighed, and the anterior tibial muscle was designated for histomorphological analyses (n = 6/group)., Results: Monosodium glutamate offspring showed significant muscle changes, such as a reduction in the size of fibres and neuromuscular junctions, and an increase in the nucleus and capillaries. However, all these changes were more expressed in monosodium glutamate-obese with periodontitis offspring., Conclusion: This leads us to suggest a magnifying effect promoted by periodontitis to the damage already well described by monosodium glutamate-obesity, determined by low-intensity inflammation, causing greater muscle damage., (© 2024 Wiley Periodicals LLC.)

Background: Whole-body vibration (WBV) is used to enhance physical performance in sports and rehabilitation. The present study analyzed the effects of remobilization with WBV on the soleus muscle of Wistar rats., Methods: Twenty-eight animals were separated into four experimental groups (n = 7): CON (control); IM (immobilized); FR (immobilization and free remobilization); and WBV (immobilization and remobilization with WBV). The immobilization of the pelvic limb was carried out according to the standard protocol using a plaster cast for 15 days. For remobilization with WBV, a Frequency of 60 Hz was applied for 10 min, five days a week, for two weeks. After the remobilization period, the animals were euthanized, and the right soleus muscle was dissected followed by processing for histomorphometric analysis and immunolocalization of Aquaporin 1 (AQP1)., Results: We observed a reduced larger diameter in IM compared to CON, with restored values in WBV. For the estimation of connective tissue, a significant increase was observed in the immobilized groups, while a reduction was noted in the remobilized groups. AQP1 expression decreased significantly in IM and increased in WBV., Conclusion: Immobilization caused morphofunctional damage to the soleus muscle, and remobilization with WBV is efficient and offers advantages over free remobilization.

Skeletal muscle histopathological changes induced or caused by pathologies in animal models, can impair functionality, being the main focus of therapeutic studies. This study aimed to propose a histopathological index to assess, in a quantitative manner, skeletal muscle changes induced by experimental protocols for Rodentia's models. For the development, evaluation of fit and parsimony, replicability, and sensitivity index, Wistar rats from experiments with the same experimental design, but with different variation factors, were used to achieve different levels of damage. The anterior tibial muscle of these animals was collected, processed histologically, and stained with hematoxylin and eosin. The adjustment and parsimony of the index were availed through Confirmatory Factor Analysis, reproducibility for evaluation of three people trained through the Intra-Class Correlation, and the discrimination capacity through a one-way ANOVA Test. We pointed out the adjustment for the proposed index while the ICC showed high reproducibility (n = 56; k = 3; ICC = 0.9790) and differences in the extent of damage between groups, following the hierarchical association promoted by experimental model stresses. The results show that the proposed index has a good fit and parsimony (χ 2 = 426.34; p < 0.0001), in addition to being easily replicable by other researchers who know the morphology of muscle tissue and its morphological changes. It is worth mentioning that the development of tools that facilitate histopathological analysis, and that can quantitatively express the findings, are of great importance for the studies of regenerative science, reinforcing the relevance of this study., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

Objective: To evaluate the morphology and morphometry of the muscles extensor digitorium longus and soleus of C57BL/6 females, who were exposed to glyphosate during pregnancy and lactation., Methods: Twelve female mice from the C57BL/6 lineage were used. After detection of pregnancy, they were divided into a Control Group, which received only water, and a Glyphosate Group, which received water with 0.5% glyphosate during pregnancy and lactation. Both groups received ad libitum standard diet. After weaning, the females were euthanized and weighed; naso-anal length was measured, and fats were collected and weighed. The muscles extensor digitorium longus and soleus were collected, and their length and weight were measured. Then, the muscles were fixed in Methacarn to perform the histological study of muscle fibers., Results: Glyphosate Group presented lower weight gain during pregnancy and also lower final body weight and naso-anal length; however, the other body parameters evaluated did not present a significant difference in relation to the Control Group. Significant differences were also not observed in the analysis of muscle fibers and connective tissue., Conclusion: Exposure to 0.5% glyphosate during pregnancy and lactation resulted in lower weight gain during pregnancy, final weight, and naso-anal length. Despite not directly altering the morphology of muscle tissue, these results may indicate enough exposure to interfere with animal metabolism.

Objectives: evaluate the effects that whole-body vibration (WBV) causes on the neuromuscular junctions and oxidative stress of the soleus muscle of obese Wistar rats., Methods: 32 male Wistar rats were used, 16 of which were obesity induced by monosodium glutamate, randomized into four groups: control (GC), control with WBV (GCP), obese (GO) and obese with WBV (GOP). At the 70 days old, the training on WBV was started, performed 3 times a week, during 8 consecutive weeks. At the 130 days old, the animals were euthanized and the soleus muscles were collected., Results: Regarding the analysis of the neuromuscular junctions, the obese groups had lower mean size when compared to the control groups. On the other hand, the WBV presented higher averages when compared to the groups that did not perform the training. Regarding the oxidative stress, for the lipid peroxidation there was a significant difference between obese and non-obese animals, however, there was no difference between the animals WBV and those who did not., Conclusion: WBV promotes beneficial changes such as increased measurements of the structures of the neuromuscular junctions, but is not able to promote changes in the concentration of the cholinesterase enzyme in the synaptic cleft., Competing Interests: The authors have no conflict of interest.

Therapeutic immobilization is a common treatment for the locomotor system; however, it causes loss of muscle due to disuse, leading to protein degradation and generating atrophy of muscle cells, ultimately changing functionality. In this sense, it is important for remobilization to be initiated early and performed with appropriate therapeutic strategies that enable tissue and functional recovery. One method of remobilization is physical exercise, among which whole body vibration (WBV) has been highlighted and mainly applied in people with reduced mobility. However, there are gaps on the morphological effects WBV has on muscle tissue, so in this study we analyzed the histomorphometry of the tibialis anterior muscle (TA) of Wistar rats remobilized using WBV. For the experiment, 32 male Wistar rats were used and divided into four groups (n = 8/group). Groups consisted of: control (CG), immobilized (IG), immobilized and remobilized freely (FG), and immobilized and remobilized with WBV (WG). After the experimental period, the TA was collected and processed for analysis in light microscopy. When compared to the control group, significant morphological changes were observed, which characterize muscle atrophy and reduction of all histomorphometric parameters of the TA of the immobilized animals. Remobilized animals showed improvement in all parameters, and the WBV was not different from the free remobilization, except for the reduction of central nuclei, which can be related to acceleration of the process of tissue regeneration. Thus, we can conclude that the WBV can have an impact on the acceleration of the muscle regenerative process, and may be beneficial in people with reduced mobility., (© 2020 American Association for Anatomy.)

Purpose: The aim of this study was to analyze the effects of mechanical vibration on the histomorphometry and oxidative stress of oophorectomized rats., Method: Seventy-two Wistar rats were randomized to Pseudoophorectomy (P) and Oophorectomy (O) and subdivided into untreated animals and euthanized after four (P4 and O4) and eight (P8 and O8) weeks and animals treated during four (PT4 and OT4) and eight (PT8 and OT8) weeks. The treatment consisted of use of whole-body vibration for 10 min, three times a week. After euthanasia, the soleus muscle was collected. The general morphological analysis was performed in the right soleus muscle and then the cross-sectional area, the largest and the smallest diameter of the muscle fiber in 100 fibers per muscle, also the nuclei and capillary/fiber ratios, and percentage of connective tissue were measured. The left soleous was used for oxidative stress analysis., Results: PT4 presented higher values in cross-sectional area than P4 and PT8, while O8 was lower than O4, P8 and OT8; for the fiber diameters, the oophorectomized animals had lower values than the pseudo-oophorectomized animals and the treatments values higher than the ones that had no treatment. In oxidative stress, O8 and OT8 presented higher lipoperoxidation, without any alterations to the activities of superoxide dismutase, catalase and cholinesterase., Conclusion: Whole-body vibration induced muscle hypertrophy in the pseudo-oophorectomized rats after four weeks, as well as being able to reverse the changes caused by the surgery in eight weeks in that variable., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Objective: Traumatic injuries are common and may promote disruption of neuromuscular communication, triggering phenomena that lead to nerve degeneration and affect muscle function. A laser accelerates tissue recovery; however, the parameters used are varied, making it difficult to compare studies. The purpose of this study was to evaluate the effect of low-level laser therapy, at 660- and 830-nm wavelengths, on the tibialis anterior muscle of Wistar rats after sciatic nerve compression., Methods: Twenty animals were separated into 4 groups: control, sciatic nerve injury, lesion + 660-nm laser, and lesion + 830-nm laser. In the lesion groups, the right sciatic nerve was surgically exposed and compressed with hemostatic forceps for 30 seconds. After the third postoperative day, the groups with laser therapy were submitted to treatment for 2 weeks totaling 10 applications, performed directly on the surgical scar of the nerve injury. Grip strength was analyzed before and after the nerve injury and during the treatment period. The tibialis anterior muscle was processed for light microscopy, area measurement, smaller diameter, number of fibers, nuclei, and connective tissue., Results: The animals submitted to the injury experienced muscular atrophy and morphological changes in the number of muscle fibers and nuclei. In the connective tissue morphometry, there was a decrease in the treated groups compared with the untreated groups., Conclusion: The laser treatment at different wavelengths showed no improvement in the tibialis anterior muscle of Wistar rats within the morphological and functional aspects evaluated., (Copyright © 2020. Published by Elsevier Inc.)

Objective To analyze the combined effects of the silk protein sericin and swimming exercise on histomorphometry of the plantar muscle in Wistar rats. Methods Forty adult rats were randomly allocated into 5 groups comprising 8 animals each, as follows: Control, Injury, Sericin, Swim, and Swim plus Sericin. Three days after crushing of the sciatic nerve the rats in the Swim and Swim plus Sericin Groups were submitted to swimming exercise for 21 days. Rats were then euthanized and the plantar muscle harvested and processed. Results Cross-sectional area, peripheral nuclei and muscle fiber counts, nucleus/fiber ratio and smallest muscle fiber width did not differ significantly between groups. Morphological analysis revealed hypertrophic fibers in the Swim Group and evident muscle damage in the Swim plus Sericin and Injury Groups. The percentage of intramuscular collagen was apparently maintained in the Swim Group compared to remaining groups. Conclusion Combined treatment with sericin and swimming exercise did not improve muscle properties. However, physical exercise alone was effective in maintaining intramuscular connective tissue and preventing progression of deleterious effects of peripheral nerve injury.

This study aims to evaluate if ligature-induced periodontitis can potentiates the deleterious effects of immobilization in the skeletal striated muscle, contributing to the development of muscle atrophy due to disuse. Forty Wistar rats were divided into four groups: (1) Control Group (CG), (2) Periodontal Disease (PDG), (3) Immobilized (IG), and (4) Immobilized with Periodontal Disease (IPDG). Periodontal disease was induced for 30 days, with ligature method, and the immobilization was performed with cast bandage for 15 days. Prior to euthanasia, nociceptive threshold and muscular grasping force were evaluated. Afterwards, the soleus muscle was dissected and processed for sarcomere counting and morphological/morphometric analysis. For data analysis, was used the one-way ANOVA and post-test Tukey (p < 0.05). The IG and IPDG presented lower muscle weight, lower muscular grip strength, and less number of sarcomeres compared to CG. The PDG showed reduction of muscle strength and nociceptive threshold after 15 days of periodontal disease and increased connective tissue compared to CG. The IPDG presented lower muscle length and nociceptive threshold. The IG presented reduction in cross-sectional area and smaller diameter, increase in the number of nuclei and a nucleus/fiber ratio, decrease in the number of capillaries and capillary/fiber ratio, with increase in connective tissue. The IPDG had increased nucleus/fiber ratio, decreased capillaries, and increased connective tissue when compared to the IG. The IPDG presented greater muscle tissue degeneration and increased inflammatory cells compared to the other groups. Ligature-induced periodontitis potentiated the deleterious effects of immobilization of the skeletal striated muscle.

Objective: To evaluate the action of vanillin (Vanilla planifolia) on the morphology of tibialis anterior and soleus muscles after peripheral nerve injury., Methods: Wistar rats were divided into four groups, with seven animals each: Control Group, Vanillin Group, Injury Group, and Injury + Vanillin Group. The Injury Group and the Injury + Vanillin Group animals were submitted to nerve injury by compression of the sciatic nerve; the Vanillin Group and Injury + Vanillin Group, were treated daily with oral doses of vanillin (150mg/kg) from the 3rd to the 21st day after induction of nerve injury. At the end of the experiment, the tibialis anterior and soleus muscles were dissected and processed for light microscopy and submitted to morphological analysis., Results: The nerve compression promoted morphological changes, typical of denervation, and the treatment with vanillin was responsible for different responses in the studied muscles. For the tibialis anterior, there was an increase in the number of satellite cells, central nuclei and fiber atrophy, as well as fascicular disorganization. In the soleus, only increased vascularization was observed, with no exacerbation of the morphological alterations in the fibers., Conclusion: The treatment with vanillin promoted increase in intramuscular vascularization for the muscles studied, with pro-inflammatory potential for tibialis anterior, but not for soleus muscle., Objetivo: Avaliar a ação da vanilina (Vanilla planifolia) sobre a morfologia dos músculos tibial anterior e sóleo após lesão nervosa periférica., Métodos: Ratos Wistar foram divididos em quatro grupos, com sete animais cada, sendo Grupo Controle, Grupo Vanilina, Grupo Lesão e Grupo Lesão + Vanilina. Os animais dos Grupos Lesão e Grupo Lesão + Vanilina foram submetidos à lesão nervosa por meio da compressão do nervo isquiático, e os Grupos Vanilina e Grupo Lesão + Vanilina foram tratados diariamente com doses orais de vanilina (150mg/kg) do 3o ao 21o dia após a indução da lesão nervosa. Ao término do experimento, os músculos tibial anterior e sóleo foram dissecados e seguiram o processamento de rotina em microscopia de luz, para posterior análise morfológica., Resultados: A compressão nervosa promoveu alterações morfológicas características de denervação, sendo que o tratamento com vanilina foi responsável por respostas distintas nos músculos estudados. Para o tibial anterior, houve aumento do número de células satélites, núcleos centrais e atrofia das fibras, bem como desorganização fascicular. Já no sóleo, houve apenas aumento da vascularização, sem exacerbação das alterações morfológicas nas fibras., Conclusão: O tratamento com vanilina promoveu o aumento da vascularização intramuscular para os músculos estudados, com potencial pró-inflamatório para o tibial anterior, o que não ocorreu no músculo sóleo.

Objective: To evaluate the effect of jumping in aquatic environment on nociception and in the soleus muscle of trained and not trained Wistar rats, in the treatment of compressive neuropathy of the sciatic nerve., Methods: Twenty-five Wistar rats were distributed into five groups: Control, Lesion, Trained + Lesion, Lesion + Exercise, and Trained + Lesion + Exercise. The training was jumping exercise in water environment for 20 days prior to injury, and treatment after the injury. Nociception was evaluated in two occasions, before injury and seven after injury. On the last day of the experiment, the right soleus muscles were collected, processed and analyzed as to morphology and morphometry., Results: In the assessment of nociception in the injury site, the Control Group had higher average than the rest, and the Lesion Group was larger than the Trained + Lesion and Lesion + Exercise Groups. The Control Group showed higher nociceptive threshold in paw, compared to the others. In the morphometric analysis, in relation to Control Group, all the injured groups showed decreased muscle fiber area, and in the Lesion Group was lower than in the Lesion + Exercise Group and Trained + Lesion Group. Considering the diameter of the muscle fiber, the Control Group had a higher average than the Trained + Lesion Group and the Trained + Lesion + Exercise Group; and the Lesion Group showed an average lower than the Trained + Lesion and Lesion + Exercise Groups., Conclusion: Resistance exercise produced increased nociception. When performed prior or after nerve damage, it proved effective in avoiding hypotrophy. The combination of the two protocols led to decrease in diameter and area of the muscle fiber., Objetivo: Avaliar os efeitos do salto em meio aquático, na nocicepção e no músculo sóleo, em ratos Wistar treinados e não treinados, no tratamento de neuropatia compressiva do nervo isquiático., Métodos: Foram distribuídos em cinco grupos 25 ratos Wistar: Controle, Lesão, Treinado + Lesão, Lesão + Exercício e Treinado + Lesão + Exercício. O treino foi com exercício de salto em meio aquático durante 20 dias, prévio à lesão, e o tratamento ocorreu após a lesão. Foram realizadas avaliações da nocicepção, sendo uma pré-lesão e sete pós-lesão. No último dia de experimento, os músculos sóleos direitos foram coletados, processados e analisados por meio de morfologia e morfometria., Resultados: Na avaliação da nocicepção no local da lesão, o Grupo Controle apresentou média maior que os demais, e o Grupo Lesão foi maior que os Grupos Treinado + Lesão e Lesão + Exercício. O Grupo Controle apresentou limiar nociceptivo na pata maior com relação aos demais. Nas análises morfométricas, em relação ao Grupo Controle, todos os grupos lesionados apresentaram diminuição da área da fibra muscular; o Grupo Lesão apresentou-se menor que os Grupos Treinado + Lesão e Lesão + Exercício. No diâmetro da fibra muscular, o Grupo Controle apresentou média maior que os Grupos Treinado + Lesão e Treinado + Lesão + Exercício, e o Grupo Lesão apresentou média menor que os Grupos Treinado + Lesão e Lesão + Exercício., Conclusão: O exercício físico resistido produziu aumento da nocicepção. Quando realizado previamente ou após a lesão nervosa, mostrou-se eficaz em evitar a hipotrofia. A associação dos dois protocolos levou à diminuição do diâmetro e da área da fibra muscular.

Objective: To evaluate the effect of jumping in aquatic environment on nociception and in the soleus muscle of trained and not trained Wistar rats, in the treatment of compressive neuropathy of the sciatic nerve. Methods: Twenty-five Wistar rats were distributed into five groups: Control, Lesion, Trained + Lesion, Lesion + Exercise, and Trained + Lesion + Exercise. The training was jumping exercise in water environment for 20 days prior to injury, and treatment after the injury. Nociception was evaluated in two occasions, before injury and seven after injury. On the last day of the experiment, the right soleus muscles were collected, processed and analyzed as to morphology and morphometry. Results: In the assessment of nociception in the injury site, the Control Group had higher average than the rest, and the Lesion Group was larger than the Trained + Lesion and Lesion + Exercise Groups. The Control Group showed higher nociceptive threshold in paw, compared to the others. In the morphometric analysis, in relation to Control Group, all the injured groups showed decreased muscle fiber area, and in the Lesion Group was lower than in the Lesion + Exercise Group and Trained + Lesion Group. Considering the diameter of the muscle fiber, the Control Group had a higher average than the Trained + Lesion Group and the Trained + Lesion + Exercise Group; and the Lesion Group showed an average lower than the Trained + Lesion and Lesion + Exercise Groups. Conclusion: Resistance exercise produced increased nociception. When performed prior or after nerve damage, it proved effective in avoiding hypotrophy. The combination of the two protocols led to decrease in diameter and area of the muscle fiber. [ABSTRACT FROM AUTHOR]