Development of a histopathological index for skeletal muscle analysis in Rattus norvegicus (Rodentia: Muridae).

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 (χ2 = 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.

Effects of oophorectomy on the lumbar spine of Wistar rats submitted to vibratory platform treatment / Efectos de la ooforectomía en la columna lumbar de las ratas de Wistar sometidas a tratamiento con plataforma vibratoria

INTRODUCTION: This study evaluated the effect of the vibratory platform on the lumbar spine morphology of Wistar rats sub-mitted to hormonal deprivation by oophorectomy. MATERIAL AND METHOD: Twenty rats were divided into four groups: Pseudo-oophorectomy (GP), Pseudo-oophorectomy Treated (GPT ), Oophorectomy (GO), Oophorectomy Treated (GOT ). After 60 days of postoperative, the treated groups started exercises on a vibratory platform in the frequency parameters of 60 Hz, alternating vibration with amplitude of 2 mm, acceleration of 57.6 m/s² and time of 10 minutes, three times in the during the four week period. Following the euthanasia of the animals, the lumbar spine was dissected and processed for analysis of the anterior and posterior longitudinal ligaments, intervertebral disc height (IVD), nucleus pulposus (NP) height, radiographic density of the lumbar vertebrae and IVD morphology. RESULTS: The results showed a decrease in the height of the NP associated to the GO and morphological alterations such as lamellar disorganization and presence of rifts in the fibrous ring, alterations of the structural limits and decrease of the NP cavity; while the other groups presented organized lamellae, peripheral and nuclear region well delimited and wide cavity of the nucleus. CONCLUSION: In this way, it can be concluded that the oophorectomy protocol promoted a decrease in the height of the NP of the IVD and that the exercise in the vibratory platform did not generate lesions in the analyzed tissues, as well as preserved the structural organization of the IVD and the height of the NP of oophorectomized rats

INTRODUCCIÓN: Este estudio evaluó el efecto de la plataforma vibratoria sobre la morfología de la columna lumbar de las ratas de Wistar sometidas a privación hormonal por ooforectomía. MATERIAL Y MÉTODO: Veinte ratas fueron divididas en cuatro grupos: Pseudo-ooforectomía (GP), Pseudo-ooforectomía tratada (GPT ), Ooforectomía (GO), Ooforectomía tratada (GOT ). Después de 60 días de postoperatorio, los grupos tratados iniciaron los ejercicios en una plataforma vibratoria en los parámetros de frecuencia de 60 Hz, alternando vibración con amplitud de 2 mm, aceleración de 57,6 m/s² y tiempo de 10 minutos, tres veces en el período de cuatro semanas. Tras la eutanasia de los animales, la columna lumbar fue diseccionada y procesada para el análisis de los ligamentos longitudinales anteriores y posteriores, la altura del disco intervertebral (DIV ), la altura del núcleo pulposo (NP), la densidad radiográfica de las vértebras lumbares y la morfología del DIV. RESULTADOS: Los resultados mostraron una disminución en la altura del PN asociado al GO y alteraciones morfológicas tales como desorganización laminar y presencia de fisuras en el anillo fibroso, alteraciones de los límites estructurales y disminución de la cavidad del PN; mientras que los otros grupos presentaron láminas organizadas, región periférica y nuclear bien delimitadas y amplia cavidad del núcleo. CONCLUSIÓN: De esta manera, se puede concluir que el protocolo de ooforectomía promovió una disminución en la altura del PN de la IVD y que el ejercicio en la plataforma vibratoria no generó lesiones en los tejidos analizados, además de preservar la organización estructural de la IVD y la altura de la NP de las ratas ooforectomizadas

Morphometric Effects of Whole-Body Vibration on the Bone in a Rat Model of Postmenopausal Osteoporosis.

OBJECTIVE: The purpose of this study was to analyze the morphometric effects of mechanical vibration with a duration of 4 or 8 weeks on the femur of oophorectomized Wistar rats. METHODS: Sixty-four female rats were submitted to oophorectomy or a sham operation, and each of those 2 groups were randomized into 4 groups: untreated and euthanized at week 12, untreated and euthanized at week 16, treated for 4 weeks and euthanized at week 12, and treated for 8 weeks and euthanized at week 16. The vibration treatment was performed for 10 min/d, with a frequency of 60 Hz, 3 d/wk. The rats were then euthanized and the right femur dissected. Subsequently, histomorphometric analysis was performed on the proximal epiphysis and diaphysis of the spongy and cortical bone, respectively. RESULTS: As expected, the oophorectomy groups presented reduction of spongy and cortical bone tissue. Further, the vibration therapy of 4 and 8 weeks' duration in the oophorectomized groups led to increased bone mass, observed as an increased percentage of spongy tissue, and increased thickness and percentage of cortical tissue. However, the variables of femoral neck diameter, mean area of the shaft, and number of osteocytes were not altered by oophorectomy and vibration. CONCLUSION: The mechanical vibration was effective in increasing the bone mass of the femur of oophorectomized Wistar rats, observed by increasing the percentage of spongy bone and increasing the percentage and thickness of cortical bone.

Short-term effects of whole-body vibration on the soleus of ooforectomized rats: Histomorphometric analysis and oxidative stress in an animal model.

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.

Evaluation of nociception induced by whole-body vibration remobilization in Wistar rats / Avaliação da nocicepção induzida pela remobilização com vibração de corpo inteiro em ratos Wistar

ABSTRACT BACKGROUND AND OBJECTIVES: The vibrating platform can attenuate the deleterious effects of immobilization related to muscle atrophy. However, there is still a gap regarding the effect of this modality on hyperalgesia related to immobilization. The objective of this study was to analyze the effect of remobilization with whole-body vibration on the nociception of Wistar rats. METHODS: Sixteen rats were randomly distributed into two groups: the FRG group - immobilization and free remobilization and the VPRG - immobilization and remobilization with the vibrating platform. For remobilization with the vibrating platform, the frequency of 60Hz for 10 minutes, five days a week for two weeks was used. The nociception was evaluated on the right paw by a digital analgesiometer, before and at the end of the immobilization, and after two weeks of remobilization. RESULTS: There were differences between evaluations but not between groups, indicating that immobilization reduced the nociceptive threshold and free remobilization, and the remobilization associated with vibration improved the nociceptive threshold compared to the post-immobilization moment. However, they were not able to return to the initial parameters. CONCLUSION: Joint immobilization reduced the nociceptive threshold; however, two weeks of whole-body vibration remobilization were not able to revert the threshold in the immobilized groups.

RESUMO JUSTIFICATIVA E OBJETIVOS: A plataforma vibratória pode atenuar os efeitos deletérios da imobilização relacionados à atrofia muscular, contudo, ainda há uma lacuna com relação ao efeito desta modalidade na hiperalgesia relacionada ao imobilismo. Assim, o objetivo deste estudo foi analisar o efeito da remobilização com plataforma vibratória sobre a nocicepção de ratos Wistar. MÉTODOS: Dezesseis ratos foram distribuídos aleatoriamente no grupo GRL - imobilização e remobilização livre, e no grupo GRPV - imobilização e remobilização com plataforma vibratória. Para a remobilização com plataforma vibratória foi utilizada a frequência de 60Hz, durante 10 minutos, cinco dias por semana, durante duas semanas. A nocicepção foi avaliada na pata direita, por meio de um analgesímetro digital, antes e ao final da imobilização, e após duas semanas de remobilização. RESULTADOS: Houve diferenças entre as avaliações, mas não entre os grupos, indicando que a imobilização reduziu o limiar nociceptivo, e a remobilização livre e associada à vibração melhoraram o limiar nociceptivo comparados com o momento pós-imobilização, no entanto, não foram capazes de retornar aos parâmetros iniciais. CONCLUSÃO: A imobilização articular reduziu o limiar nociceptivo. No entanto, duas semanas de remobilização com a vibração de corpo inteiro não foram capazes de reverter o limiar nos grupos imobilizados.

Low-Level Laser Effect on Peripheral Sciatic Regeneration Under the Systemic Inflammatory Condition of Periodontal Disease.

Introduction: Periodontal disease (PD) is an inflammatory condition, which leads to tooth loss and promotes a systemic inflammatory state that can aggravate the nerve degeneration. As laser therapy may stimulate regeneration, this study aimed to evaluate the effect of the low-level laser (LLL) on peripheral nerve regeneration under the systemic inflammatory condition of PD. Methods: Thirry-two male rats were used, distributed in 4 groups: nerve injury (NIG); periodontal disease with nerve injury (PDNI); nerve injury and treatment (TNIG); periodontal disease with nerve injury and treatment (PDNIT). On the 7th day of the experiment, the animals had ligatures placed around the lower first molars. On the 22nd day, they underwent peripheral nerve damage, and on the 25th day, the LLL treatment was initiated, performed for two weeks. The sciatic functional index (SFI) was evaluated with subsequent euthanasia of all the animals on the 37th day of the experiment. The sciatic nerve was collected for morphological and oxidative stress analysis and the hemi jaws for radiographic analysis. Results: Regarding the SFI, there was no difference among the groups in the first evaluation (EV) pre-injury; as for theEV2, after injury, all the groups presented a decrease in these values, which remained in post-treatment. For the morphology of the PDNI, nerve tissue presented larger diameter fibers, whereas, for NIT and PDNIT, fibers had smaller diameters with endoneurial organization. When it comes to the antioxidant system, there was an increase in protein concentration, higher superoxide activity, and decreased glutathione transferase activity in the treated groups. Catalase and cholinesterase did not differ between the groups, and lipoperoxidation (LPO) increased in the PD groups. For the mandible radiographic analysis, it was possible to verify the induction of PD. Conclusion: As for the used parameters, the low-level laser was not effective in increasing the nociceptive threshold, but it contributed to the regeneration of nerve fibers, although the inflammation was still present in the site. However, the treatment was effective in protecting cells against oxidative damage due to increased SOD and increased protein, although the decrease in GST demonstrates the inhibition of this stage of the antioxidant system.

Effects of Mechanical Vibration in Neuromuscular Junctions and Fiber Type of the Soleus Muscle of Oophorectomized Wistar Rats.

Objective To evaluate the neuromuscular junctions (NMJs) and the type of muscle fibers of the soleus muscle of oophorectomized Wistar rats submitted to a mechanical vibration protocol. Methods A total of 36 randomized rats were used in the pseudo-oophorectomy without and with treatment and oophorectomy without and with treatment groups. The treatment was performed with a vibratory platform, frequency of 60 Hz and duration of 10 minutes, 3 times a week, for 4 weeks. At the end of the intervention period, the animals were euthanized and the soleus muscles were collected and processed for analysis of the NMJs and fiber type. The data were analyzed for normality by the Shapiro-Wilk test and analysis of the 3-way variance using the post-hoc Tukey test, when necessary, and a significance level of 5% was adopted. Results In the analysis of the NMJs, the oophorectomy group presented a smaller area than the pseudo-oophorectomy group, but the oophorectomy with treatment group was equal to the pseudo-oophorectomy with treatment group. For the larger diameter of the joints, the oophorectomy group was also different from the others; however, the oophorectomy and treatment animals were larger than those of the pseudo-oophorectomy and treatment group. There was no distinction of the types of fibers, with the muscle presenting fibers of the oxidative type. Conclusion Hormonal deprivation reduced the area and diameter of the NMJs, with reversion of this process in the groups that underwent vibratory platform treatment for 4 weeks, and both surgery and treatment did not influence the type of soleus muscle fiber, composed of oxidative fibers.

Effects of Mechanical Vibration in Neuromuscular Junctions and Fiber Type of the Soleus Muscle of Oophorectomized Wistar Rats / Efeitos da vibração mecânica nas junções neuromusculares e tipo de fibra do músculo sóleo de ratas wistar ooforectomizadas

Abstract Objective To evaluate the neuromuscular junctions (NMJs) and the type of muscle fibers of the soleus muscle of oophorectomized Wistar rats submitted to a mechanical vibration protocol. Methods A total of 36 randomized rats were used in the pseudo-oophorectomy without and with treatment and oophorectomy without and with treatment groups. The treatment was performed with a vibratory platform, frequency of 60 Hz and duration of 10 minutes, 3 times a week, for 4 weeks. At the end of the intervention period, the animals were euthanized and the soleus muscles were collected and processed for analysis of the NMJs and fiber type. The data were analyzed for normality by the Shapiro-Wilk test and analysis of the 3-way variance using the post-hoc Tukey test, when necessary, and a significance level of 5% was adopted. Results In the analysis of the NMJs, the oophorectomy group presented a smaller area than the pseudo-oophorectomy group, but the oophorectomy with treatment group was equal to the pseudo-oophorectomy with treatment group. For the larger diameter of the joints, the oophorectomy group was also different from the others; however, the oophorectomy and treatment animals were larger than those of the pseudo-oophorectomy and treatment group. There was no distinction of the types of fibers, with the muscle presenting fibers of the oxidative type. Conclusion Hormonal deprivation reduced the area and diameter of the NMJs, with reversion of this process in the groups that underwent vibratory platform treatment for 4 weeks, and both surgery and treatment did not influence the type of soleus muscle fiber, composed of oxidative fibers.

Resumo Objetivo Avaliar as junções neuromusculares (JNMs) e o tipo de fibras musculares do músculo sóleo de ratas Wistar ooforectomizadas e submetidas a um protocolo de vibração mecânica. Métodos Foram utilizadas 36 ratas randomizadas nos grupos pseudo-ooforectomia sem e com tratamento e ooforectomia sem e com tratamento. O tratamento foi realizado com plataforma vibratória, frequência de 60 Hz e duração de 10 minutos, 3 vezes por semana, durante 4 semanas. Ao término do período de intervenção, os animais foram eutanasiados e os músculos sóleos coletados e processados para análise das JNMs e tipo de fibra. Os dados foram analisados quanto à normalidade pelo teste Shapiro-Wilk e análise da variância de 3 vias, utilizando o pós-teste de Tukey quando necessário, tendo sido adotado o nível de significância de 5%. Resultados Na análise das JNMs, o grupo ooforectomia apresentou área menor que o grupo pseudo-ooforectomia, porém o grupo ooforectomia tratado igualou-se ao grupo pseudo-ooforectomia tratado. Para o maior diâmetro das junções, o grupo ooforectomia também se apresentou diferente dos demais; porém, os animais do grupo ooforectomia tratado foram maiores que o grupo pseudo-ooforectomia tratado. Não houve distinção dos tipos de fibras, com o músculo apresentando fibras do tipo oxidativo. Conclusão A privação hormonal reduziu a área e o diâmetro das JNMs, com reversão deste processo nos grupos que realizaram o tratamento com plataforma vibratória durante 4 semanas e, ainda, tanto cirurgia quanto tratamento não influenciaram no tipo de fibra do músculo sóleo, composto por fibras oxidativas.

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

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.(AU)

Sericin and swimming on histomorphometric parameters of denervated plantar muscle in Wistar rats.

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.

Sericin and swimming on histomorphometric parameters of denervated plantar muscle in Wistar rats / Sericina e natação sobre parâmetros histomorfométricos de músculo plantar desnervado de ratos Wistar

Abstract 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.

RESUMO Objetivo Analisar o efeito da proteína sericina associada ao exercício físico de natação na histomorfometria do músculo plantar de ratos Wistar. Métodos Foram utilizados 40 ratos adultos divididos aleatoriamente em 5 grupos, com 8 animais cada: Controle, Lesão, Sericina, Natação, Natação e Sericina. Três dias após a compressão do nervo isquiático, os Grupos Natação e Exercício e Sericina foram submetidos ao exercício físico de natação durante 21 dias. Após, os animais foram sacrificados, e o músculo plantar foi processado. Resultados Não houve diferença da área da secção transversa entre os grupos, quantidade de núcleos periféricos, quantidade de fibra, relação núcleo/fibra e diâmetro menor. A análise morfológica revelou que no Grupo Natação ocorreu hipertrofia das fibras, assim como nos Grupos Exercício e Sericina e Lesão, o dano muscular foi evidente. O percentual de conjuntivo intramuscular parece ter sido mantido no Grupo Exercício em relação aos demais grupos. Conclusão A associação da proteína sericina e exercício físico de natação não foi eficiente na melhora das propriedades musculares, embora a aplicação do exercício físico tenha sido eficiente na manutenção do conjuntivo intramuscular, e no não agravamento dos efeitos deletérios consequentes da lesão nervosa periférica.

Action of vanillin (Vanilla planifolia) on the morphology of tibialis anterior and soleus muscles after nerve injury.

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.

Action of vanillin (Vanilla planifolia) on the morphology of tibialis anterior and soleus muscles after nerve injury / Ação da vanilina (Vanilla planifolia) sobre a morfologia dos músculos tibial anterior e sóleo após lesão nervosa

ABSTRACT 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.

RESUMO 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.

Ação do exercício de subida em escada com sobrecarga na morfologia do músculo tibial anterior de ratos Wistars após axonotmese / Action of the climbing ladder exercise with overload in the morphology of the anterior tibial muscle of wistars rats after axonotmesis

Objetivo: avaliar histomorfometrica e morfologicamente o músculo tibial anterior de ratos submetidos à axonotmese e tratados com exercício. Métodos: foram randomizados 28 ratos Wistar nos grupos controle (GC), exercício (GE), lesão (GL) e lesão+exercício (GLE). No terceiro dia após compressão, GE e GLE realizaram exercício de subida em escada, com duas séries de dez repetições. Após 21 dias, o músculo tibial anterior foi processado para microscopia de luz. Resultados: Na análise morfológica GC apresentou morfologia com aspecto característico, GE hipertrofia muscular, GL alterações morfológicas, como fibras polimórficas e núcleos centrais, e GLE aspecto semelhante ao controle, porém com algumas alterações. Na área de secção transversa e menor diâmetro das fibras GC e GE apresentaram valores maiores, o inverso da análise de vasos sanguíneos. Para o tecido conjuntivo, GE apresentou-se menor que o GL. Conclusão: O protocolo de exercício promoveu melhora nos aspectos histomorfológicos, mas não reverteu totalmente os efeitos deletérios. (AU)

Objective: to evaluate morphologically the tibialis anterior muscle of rats submitted to axonotmosis and treated with exercise. Methods: 28 Wistar rats were used in groups control (CG), exercise (GE), injury (GL) and injury + exercise (GLE). On the third day after compression, GE and GLE performed climb exercise staircase, with two sets of ten repetitions. After 21 days, the muscle was processed for light microscopy. Results: In the morphological analysis GC presented with morphology characteristic appearance, GE muscle hypertrophy, GL morphological changes like polymorphic fibers and central nucleo, and GLE look similar to the control, but with some changes morphological. In the cross-sectional area and smaller diameter of the GC and GE fiber showed higher values, inversed analysis of blood vessels. For the connective tissue, GE was lower than the GL. Conclusion: Summing up, the exercise promoted improvement in morphological aspects, but not totally reversed the deleterious effects of denervation. (AU)

Effects of the platelet-rich fibrin associated with physical exercise in a model of median nerve compression

AIMS: Platelet-Rich Fibrin (PRF) is a new and promising technique for tissue repair, however, there is still a gap about its action on peripheral nerve injury, as well as its association with physical exercise. Thus, the aim of this study was to evaluate the effects of the PRF associated with physical exercise in a model of median nerve compression. METHODS: 42 rats, divided into: Control, non-injured limb, and other six groups with nerve lesion (Control lesion; Treated with PRF; Treadmill walking; Free swimming; PRF and treadmill; PRF and swimming). The lesion model was performed with median nerve compression. To obtain the PRF, 1.5 mL of blood was centrifuged and the fibrin clot positioned directly over the compression region. The exercise protocols were performed during 2 weeks. The evaluations performed were grip strength tests and histologic analysis. RESULTS: both, grip strength and histomorphometric evaluations (fiber numbers and axon density) did not present significant differences between the treated and lesion groups, however, in the morphological evaluation it was possible to distinguish characteristics of the repair process for the treated groups. CONCLUSION: a slight qualitative improvement was observed for the treated groups, especially when it was associated PRF with free swimming.(AU)

Nociceptive and Neuronal Evaluation of the Sciatic Nerve of Wistar Rats Subjected to Compression Injury and Treated with Resistive Exercise.

Background. To investigate the climb stairs resistance exercise on nociception and axonal regeneration in the sciatic nerve of rats. Methods. 24 Wistar rats were divided: control group (CG-no injury), exercise group (EG-no injury with physical exercise), lesion group (LG-injury, but without exercise), and treated group (LEG-injury and physical exercise). LG and LEG were subjected to sciatic nerve compression with hemostat. From the 3rd day after injury began treatment with exercise, and after 22 days occurs the removal of a nerve fragment for morphological analysis. Results. Regarding allodynia, CG obtained values less than EG (p = 0.012) and larger than LG and LEG (p < 0.001). Histological results showed that CG and EG had normal appearance, as LG and LEG showed up with large amounts of inflammatory infiltration, degeneration and disruption of nerve fibers, and reduction of the myelin sheath; however LEG presented some regenerated fibers. From the morphometric data there were significant differences, for nerve fiber diameter, comparing CG with LG and LEG and comparing axon diameter and the thickness of the myelin of the CG to others. Conclusion. Climb stairs resistance exercise was not effective to speed up the regenerative process of axons.

Efeito do exercício resistido na redução do edema, nocicepção e regeneração nervosa em um modelo de compressão do nervo isquiático / Effect of resistance training on the reduction of edema, nociception, and nerve regeneration in a sciatic nerve compression model

OBJETIVOS: Analisar os efeitos do exercício físico resistido de subida em escada, sobre o edema, nocicepção e regeneração nervosa de ratos Wistar, submetidos à compressão do nervo isquiático. MÉTODOS: Foram estudados 24 ratos Wistar, divididos igualmente entre quatro grupos: Grupo Controle, Grupo Exercício, Grupo Lesão e Grupo Tratado ­ Lesão e Exercício. O Grupo Lesão e o Grupo Tratado foram submetidos à compressão do nervo isquiático com pinça hemostática por 30 segundos. A partir do terceiro dia após a lesão, iniciou-se o tratamento com exercício resistido de subida em escada para o Grupo Exercício e o Grupo Tratado. O tratamento consistiu em realizar duas séries de 10 subidas na escada, com sobrecarga de 100 gramas e intervalo de um minuto entre uma série e outra. O estudo foi conduzido por 22 dias e nesse tempo os animais foram avaliados quanto ao edema e à nocicepção. No 22º dia de pós-operatório, os animais foram anestesiados para retirada de um fragmento do nervo isquiático para análise do número de axônios e da densidade de fibras. Em seguida, ainda sob efeito da anestesia, os animais foram eutanasiados. Os nervos coletados seguiram protocolo de processamento histológico de rotina. As expressões do Fator de Crescimento Neural e do Fator de Crescimento Derivado do Cérebro foram avaliadas por Western blotting. RESULTADOS: Não houve diferença significativa entre os grupos no tamanho do edema. O Grupo Controle apresentou maior limiar nociceptivo comparado aos demais grupos. A análise morfométrica não revelou diferença significativa entre os grupos, quanto à quantidade de axônios e à densidade de fibras. A expressão do Fator de Crescimento Derivado do Cérebro foi maior no Grupo Lesão e no Grupo Tratado quando comparados ao Grupo Controle. CONCLUSÕES: O exercício físico resistido de subida em escada, nos parâmetros propostos, não foi eficaz para reduzir o edema, a nocicepção ou aumentar o número de axônios e a densidade de fibras nervosas após lesão do nervo isquiático.

AIMS: To analyze the effects of ladder-climbing resistance training exercise on edema, nociception, and regeneration of the sciatic nerve in Wistar rats subjected to sciatic nerve compression. METHODS: Twenty-four Wistar rats were divided into four groups: Control Group, Exercise Group, Injury Group, and Treated Group (injury and exercise). Injury Group and Treated Group were subjected to sciatic nerve compression with a hemostat for 30 seconds. On the third day after injury, Exercise Group and Treated Group began treatment with ladder-climbing resistance exercise. The treatment consisted in performing two series of 10 ladder climbs with a 100-gram overload and a one-minute interval between the series. The study was conducted for 22 days, during which time the animals were evaluated for edema and nociception. Twenty-two days after surgery, the animals were anesthetized for removal of a sciatic nerve fragment and analysis of the number of axons and fiber density. Thereafter, still under anesthesia, the animals were euthanized. Nerve sampling followed the routine histological processing protocol. Expressions of Neural Growth Factor and Brain-derived Neurotrophic Factor were evaluated by Western blotting. RESULTS: There was no significant difference in edema size between groups. Control Group showed the highest nociceptive threshold compared to the other groups. The morphometric analysis showed no significant difference in number of axons and fiber density between groups. The expression of Brain-derived Neurotrophic Factor was greater in the Injury Group and the Treated Group compared to the Control Group. CONCLUSIONS: The proposed ladder-climbing resistance training was not effective in reducing edema and nociception or in increasing the number of axons and fiber density after sciatic nerve injury.

Avaliação nociceptiva da associação entre exercício físico e fibrina rica em plaquetas em ratos Wistar submetidos ao modelo de compressão de nervo mediano / Nociceptive evaluation of the association between physical exercises and platelet-rich fibrin in Wistar rats submitted to median nerve compression

RESUMO JUSTIFICATIVA E OBJETIVOS: Fibrina rica em plaquetas é uma técnica nova e promissora na aceleração do reparo, com possíveis efeitos analgésicos, contudo, ainda há uma lacuna com relação à lesão nervosa periférica, bem como com a associação com exercícios físicos. Assim, o objetivo deste estudo foi avaliar os efeitos da fibrina rica em plaquetas associada a exercício físico sobre a nocicepção e o edema, em modelo experimental de compressão do nervo mediano. MÉTODOS: Foram utilizados 36 ratos, todos submetidos a compressão do nervo mediano e divididos em seis grupos: G1: sem manipulações adicionais; G2: compressão e tratado com fibrina rica em plaquetas; G3: compressão e tratado com natação livre; G4: compressão e exercício de caminhada em esteira; G5: natação livre + fibrina rica em plaquetas; G6: caminhada em esteira + fibrina rica em plaquetas. O modelo de lesão foi realizado com amarria do nervo mediano, com fio catgut 4.0 cromado. Para obtenção da fibrina rica em plaquetas, 1,5mL de sangue foi centrifugado e o coágulo de fibrina foi posicionado diretamente sobre a região da compressão. Os protocolos de exercício foram realizados durante 2 semanas, entre o 3º e 14º dias de pós-operatório. As avaliações nociceptivas e de edema ocorreram, respectivamente, pelo limiar de retirada de pata e pletismometria, nos momentos prévios à lesão, no 3º, 7º e 15º dias de pós-operatório. RESULTADOS: Não houve diferenças entre os grupos, apenas entre as avaliações, denotando que houve aumento da nocicepção e do edema, o qual perdurou ou foi decaindo, respectivamente, com o passar do tempo. CONCLUSÃO: O uso isolado ou associado da fibrina rica em plaquetas com exercícios físicos não produziu alterações na nocicepção e edema.

ABSTRACT BACKGROUND AND OBJECTIVES: Platelet-rich fibrin is a new and promising technique to accelerate repair, with possible analgesic effects; however, there is still a gap with regard to peripheral nerve injury and the association with physical exercises. So, this study aimed at evaluating the effects of platelet-rich fibrin associated to physical exercises on nociception and edema in experimental median nerve compression model. METHODS: Thirty-six rats, all submitted to median nerve compression, were divided in six groups: G1: without additional manipulation; G2: compression and treated with platelet-rich fibrin; G3: compression and treated with free swimming; G4: compression and walking on a treadmill; G5: free swimming + platelet-rich fibrin; G6: walking on a treadmill + platelet-rich fibrin. Injury was induced by tying the median nerve with chrome plated catgut 4.0. Platelet-rich fibrin was obtained by centrifuging 1.5 mL of blood and positioning the fibrin clot directly on the compression region. Exercises were carried out during two weeks, between the 3rd and 14th postoperative days. Nociception and edema were evaluated, respectively, by flinch threshold and plethysmometer, in moments before injury and in the 3rd, 7th and 15th postoperative days. RESULTS: There have been no differences among groups, only among evaluations, showing increased nociception and edema, which has lasted or improved, respectively, over time. CONCLUSION: Platelet-rich fibrin alone or associated to physical exercises has not changed nociception and edema.

Mobilização neural aplicada em diferentes locais sobre a compressão do nervo isquiático de ratos Wistar / Neural mobilization applied at different sites on the sciatic nerve compression in Wistar rats

Introdução: a mobilização neural é uma técnica que visa restituir a função do sistema nervoso, contudo há ainda desconhecimento sobre o local mais apropriado. Objetivos: avaliar os efeitos da mobilização neural no tratamento da compressão do nervo isquiático de ratos Wistar, e comparar os diferentes locais de aplicação. Métodos: 24 ratos Wistar foram submetidos à compressão do nervo isquiático direito, e separados em quatro grupos: lesão (GL), mobilização neural no lesionado (GPD), mobilização neural no membro contralateral (GPE) e mobilização neural no membro ipsilateral a lesão (GEP). Foram realizadas avaliações funcionais pelo tempo de elevação da pata (TEP) e dolorímetro digital de Von Frey, após a última avaliação, o nervo isquiático foi seccionado para análise histológica. Resultados: houve diferença entre o GL (23,54) e GPE (23,98) na avaliação do TEP (p=0,028), na avaliação nociceptiva e histológica não houve diferenças significativas (p>0,05). Conclusão: a mobilização neural no membro contralateral foi prejudicial, enquanto o tratamento no membro acometido e no membro ipsilateral não apresentou diferença significativa.

Introduction: neural mobilization is a technique that aims to restore the function of the nervous system, yet there still lack of knowledge about the most appropriate place. Objectives: to evaluate the effects of neural mobilization in the treatment of sciatic nerve compression Wistar rats, and compare the different application sites. Methods: 24 Wistar rats were right sciatic nerve compression, and separated into four groups: injury (GL), neural mobilization in the injured (GPD), neural mobilization in the contralateral limb (GPE) and neural mobilization in the ipsilateral limb injury (GEP). Functional assessments were performed at paw elevation time (TEP) and digital Von Frey dolorimeter after the last evaluation, the sciatic nerve was sectioned for histological analysis. Results: there was a difference between the GL (23.54) and GPE (23.98) in the evaluation of the TEP (p=0.028), in nociceptive and histological evaluation no significant differences (p>0.05). Conclusion: the neural mobilization held in the contralateral limb was harmful, while treating the affected and ipsilateral limb showed no significant difference.

Avaliação comportamental de ratos treinados em natação forçada / Behavioral assessment of rats through the forced-swimming test

Objetivos: O exercício físico regular tem diversos efeitos benéficos, contudo, há relatos de aumento na concentração de corticosteroides endógenos, os quais podem inibir a neurogênese e piorar as funções cognitivas, sendo este um aspecto dúbio do exercício físico. O objetivo deste estudo foi avaliar, por meio de testes comportamentais, o efeito do exercício crônico por natação forçada com e sem sobrecarga, sobre parâmetros de ansiedade em ratos Wistar.Métodos: Foram utilizados 24 ratos Wistar, separados em três grupos: Grupo Controle - submetido apenas a avaliações e contato com a água; Grupo Natação - composto por animais submetidos à natação com tempo progressivo; Grupo Natação com Sobrecarga - composto por animais submetidos à natação com sobrecarga de 10% do peso corporal. O exercício ocorreu três vezes por semana, no período vespertino, com aumento no tempo a cada duas semanas (20, 30 e 40 minutos), totalizando seis semanas. Foi realizado em um tanque de água circular de 200 litros, com profundidade de 50 cm e temperatura da água mantida entre 30 e 32º C. A ansiedade dos animais foi avaliada pelos testes Labirinto em Cruz Elevado e Campo Aberto.Resultados: Não houve diferenças significativas em qualquer dos testes comportamentais, comparando os três grupos.Conclusões: Não houve alteração no padrão comportamental de ratos Wistar submetidos a diferentes protocolos de exercício (natação forçada com e sem sobrecarga) quando comparados ao grupo controle não submetido a exercícios.

Aims: Regular exercise has several beneficial effects. However, reports show increasing concentrations of endogenous corticosteroids, which may inhibit neurogenesis and deteriorate cognitive functions, thus raising doubts as to the benefits of physical exercise. The objective of this study was to evaluate, through behavioral tests, the effect of chronic forced swimming with and without overload on anxiety parameters in Wistar rats. Methods: Twenty-four Wistar rats, divided into three groups, were assessed: Control Group - subjected only to evaluations and contact with water; Swimming Group - consisting of animals submitted to progressive swimming time; Weight-loaded Swimming Group - consisting of animals submitted to swimming with loads in excess of 10% of their body weight. The exercise was performed three times a week in the afternoon, with swimming time increases every two weeks (20, 30, and 40 minutes), during six weeks, A 200-liter circular water tank, filled to a depth of 50 cm, was used, and the water temperature was kept between 30º and 32º C. The animals' anxiety was assessed by the Elevated Plus Maze and Open Field tests. Results: No significant differences between the three groups were detected by any of the behavioral tests.Conclusions: No changes were observed in the behavioral pattern of Wistar rats submitted to different exercise protocols (forced swimming with and without overload) compared to the control group.