RESUMO

Objective Although autologous bone grafting is the most widely used treatment for bone defects, the most effective preparation remains unclear. This animal study aimed to compare different autologous bone grafting preparation for the treatment of rat́s calvaria critical bone defect. Methods 122 rats were randomly allocated into three groups: Simulado, Macerated and Chopped. The specimens underwent craniotomies at the top center of their calvarias with a 7mm diameter circumferential cutter drill. The critical bone defect produced was treated or not according to the group the specimen wasallocated. The rats were euthanized at 3, 6 or 12 weeks post-op and its calvarias were analyzed by histomorphometry, bone densitometry, nanocomputed tomography (nCT), and biomechanical tests. Results The histomorphometry analysis showed the highest percentage of fulfillment of the critical bone defect in the chopped and macerated group when compared to simulado. The densitometry assessment evidenced higher bone mass at all endpoints analysis (p < 0.05) in the chopped group. The nCT data exhibited an expressive increase of bone in the chopped group when compared with the simulado and macerated groups. The biomechanical tests exhibited highest values of deformation, maximum force, and relative stiffness in the chopped group at any time of euthanasia (p < 0.05). Conclusions Our experimental work showed that chopped bone grafting preparation exhibited significant better outcomes than macerated in the treatment of a critical bone defect in rat́s calvaria.

RESUMO

Introdução: a hanseníase é uma do-ença infecciosa crônica causada pelo Mycobacterium leprae (M. leprae), um para-sita intracelular obrigatório. Assim, a resis-tência do hospedeiro a esse patógeno depen-de da imunidade celular. O uso de modelos experimentais tem permitido o estudo da hanseníase do ponto de vista imunológico, microbiológico e terapêutico, entretanto, as diferenças na progressão da infecção entre os modelos mais empregados (camundongos imunocompetentes, BALB/c, e camundongos congenitamente atímicos, nude) são pouco estudadas. Objetivo: comparar a evolução da infecção pelo M. leprae em camundongos BALB/c e nude quanto à multi-plicação bacilar e avaliação do perfil inflamatório sistêmico pela quantificação sérica de citocinas e óxido nítrico (NO). Métodos: os camundongos foram inoculados com M. leprae nos coxins plantares e avaliados aos 3, 5 e 8 meses após a infecção. Resultados: camundongos nude apresentaram multiplicação bacilar progressiva nos coxins plantares. Em camundongos BALB/c, o número de bacilos foi maior aos 5 meses. Em relação à quantificação de citocinas, nos camundongos BALB/c houve aumento de IL-2 e IL-17A e diminuição de IL-6 e NO aos 8 meses de inoculação. Nos camundongos nude, verificou-se o aumento do TNF aos 8 meses de inoculação e manutenção dos níveis de NO. Conclusão: os resultados encontrados sugerem que em camundongos BALB/c ocorre a ativação de uma resposta imune capaz de controlar a multiplicação do M. leprae, em contrapartida em camundongos nude a infecção é progressiva a despeito de altos níveis de TNF. (AU)

Introduction: leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae), an obligate intracellular parasite. Thus, host resistance to this pathogen depends on cellular immunity. The use of experimental models has made it possible to study leprosy from an immunological, microbiological, and therapeutic point of view. However, the differences in the progression of the infection between the most used models (immunocompetent mice, BALB/c, and congenitally athymic mice, nude) have been little studied. Objective: to compare the evolution of M. leprae infection in BALB/c and nude mice in terms of bacillary multiplication and evaluation of the systemic inflammatory profile by quantifying serum cytokines and nitric oxide (NO). Methods: the mice were inoculated with M. leprae in the footpads and evaluated at 3, 5, and 8 months after infection. Results: nude mice showed progressive bacillary multiplication in the footpads. In BALB/c mice, the number of bacilli was higher at 5 months. In terms of cytokine quantification, BALB/c mice showed an increase in IL-2 and IL-17A and a decrease in IL-6 and NO at 8 months of inoculation. In the nude mice, there was an increase in TNF at 8 months of inoculation and maintenance of NO levels. Conclusion: the results suggest that BALB/c mice activate an immune response capable of controlling the multiplication of M. leprae, whereas in nude mice the infection is progressive despite high levels of TNF. (AU)

Assuntos

RESUMO

ABSTRACT Purpose: This study aimed to evaluate a new therapeutic option for the spasticity using ultrasound neuromodulation in an animal model of spastic cerebral palsy. Methods: Thirty-two adult male Wistar rats were randomly distributed in: negative control (NC); positive control (PC); untreated model (UTM); and treated model (TM). Rats in the control groups received sham surgery, and rats in the model groups received the spastic cerebral palsy model surgery. The rats' motor functions were evaluated by the Rotarod and CatWalk tests before and after surgery. PC and TM groups underwent ultrasonic neuromodulation by a physiotherapeutic ultrasound (intensity 0.1 W/cm2, at 1 MHz) continuous mode for 5 seconds, for seven days. Results: Twelve rats showed a spastic pattern (UTM = 6 and TM = 6), motor limitations (UTM = 6 and TM = 6), and ten had difficulty feeding (UTM = 5 and TM = 5). One UTM group rat could not recover its preoperative latency time, while the other rats in the model groups did. The speed at which the limbs swung reduced after surgery and increased in subsequent assessments, demonstrating greater instability and a deficit in locomotion balance. Conclusions: Results were not yet sufficient to assert ultrasound neuromodulation as a possible therapy for spasticity in spastic cerebral palsy in the parameters used, and more studies are necessary.

RESUMO

Abstract Objective Although autologous bone grafting is the most widely used treatment for bone defects, the most effective preparation remains unclear. This animal study aimed to compare different autologous bone grafting preparation for the treatment of rats calvaria critical bone defect. Methods 122 rats were randomly allocated into three groups: Simulado, Macerated and Chopped. The specimens underwent craniotomies at the top center of their calvarias with a 7mm diameter circumferential cutter drill. The critical bone defect produced was treated or not according to the group the specimen wasallocated. The rats were euthanized at 3, 6 or 12 weeks post-op and its calvarias were analyzed by histomorphometry, bone densitometry, nanocomputed tomography (nCT), and biomechanical tests. Results The histomorphometry analysis showed the highest percentage of fulfillment of the critical bone defect in the chopped and macerated group when compared to simulado. The densitometry assessment evidenced higher bone mass at all endpoints analysis (p < 0.05) in the chopped group. The nCT data exhibited an expressive increase of bone in the chopped group when compared with the simulado and macerated groups. The biomechanical tests exhibited highest values of deformation, maximum force, and relative stiffness in the chopped group at any time of euthanasia (p < 0.05). Conclusions Our experimental work showed that chopped bone grafting preparation exhibited significant better outcomes than macerated in the treatment of a critical bone defect in rats calvaria.

Resumo Objetivo Embora enxertos ósseos autólogos sejam o tratamento mais utilizado para defeitos ósseos, a preparação mais eficaz ainda é obscura. Este estudo animal teve como objetivo comparar diferentes preparações de enxerto ósseo autólogo para o tratamento de defeito ósseo crítico no crânio de ratos. Métodos No total, 122 ratos foram alocados aleatoriamente em três grupos: Simulado, enxerto macerado e enxerto picado. Os espécimes foram submetidos a craniotomias no centro superior do crânio com broca de corte circunferencial de 7 mm de diâmetro. O defeito ósseo crítico produzido foi tratado ou não de acordo com o grupo de alocação do animal. Os ratos foram eutanasiados às 3, 6 ou 12 semanas após a cirurgia e seus crânios foram analisados por histomorfometria, densitometria óssea, nanotomografia computadorizada (nTC) e testes biomecânicos. Resultados A análise histomorfométrica mostrou maior percentual de preenchimento do defeito ósseo crítico no grupo picado e macerado em comparação ao simulado. A avaliação densitométrica evidenciou maior massa óssea em todos os desfechos de análise (p < 0,05) no grupo picado. Os dados de nTC revelaram um aumento ósseo expressivo no grupo picado em comparação aos grupos simulado e macerado. Os testes biomecânicos mostraram maiores valores de deformação, resistência máxima e rigidez relativa no grupo picado em qualquer momento da eutanásia (p < 0,05). Conclusões Nosso estudo mostrou que a preparação de enxerto ósseo picado gerou resultados significativamente melhores do que os enxertos macerados no tratamento de defeitos ósseos críticos no crânio de ratos.

RESUMO

ABSTRACT Purpose: This study aimed to introduce and evaluate two new microvascular anastomosis techniques compared to the conventional method in a rat renal transplant model. Methods: Using a Fisher-to-Lewis rat kidney transplantation model, the renal artery anastomosis was performed using the interrupted (I) suture technique, Y-shaped continuous (Y) suture technique, and anterior-interrupted and posterior-continuous (I-C) suture technique. The rats were then divided into three groups: I group, Y group, and I-C group. Parameters such as arterial anastomosis time, warm ischemia time, seven-day survival rate of the rats, and vessel histopathology were assessed. Results: The mean arterial anastomosis time, blood leakage scores, and warm ischemia time were significantly reduced in groups Y and I-C compared to group I. Moreover, the seven-day survival rate was significantly higher in the I-C group compared to the other two groups. Arterial histopathology demonstrated vessel wall recovery without damage in all three groups, suggesting the safety of both Y and I-C techniques. Conclusions: The anterior-interrupted and posterior-continuous suture method is particularly beneficial for small artery reconstruction in organ transplantation.

RESUMO

ABSTRACT Objective: To assess the effect of atelectasis during mechanical ventilation on the periatelectatic and normal lung regions in a model of atelectasis in rats with acute lung injury induced by lipopolysaccharide. Methods: Twenty-four rats were randomized into the following four groups, each with 6 animals: the Saline-Control Group, Lipopolysaccharide Control Group, Saline-Atelectasis Group, and Lipopolysaccharide Atelectasis Group. Acute lung injury was induced by intraperitoneal injection of lipopolysaccharide. After 24 hours, atelectasis was induced by bronchial blocking. The animals underwent mechanical ventilation for two hours with protective parameters, and respiratory mechanics were monitored during this period. Thereafter, histologic analyses of two regions of interest, periatelectatic areas and the normally-aerated lung contralateral to the atelectatic areas, were performed. Results: The lung injury score was significantly higher in the Lipopolysaccharide Control Group (0.41 ± 0.13) than in the Saline Control Group (0.15 ± 0.51), p < 0.05. Periatelectatic regions showed higher lung injury scores than normally-aerated regions in both the Saline-Atelectasis (0.44 ± 0.06 x 0.27 ± 0.74 p < 0.05) and Lipopolysaccharide Atelectasis (0.56 ± 0.09 x 0.35 ± 0.04 p < 0.05) Groups. The lung injury score in the periatelectatic regions was higher in the Lipopolysaccharide Atelectasis Group (0.56 ± 0.09) than in the periatelectatic region of the Saline-Atelectasis Group (0.44 ± 0.06), p < 0.05. Conclusion: Atelectasis may cause injury to the surrounding tissue after a period of mechanical ventilation with protective parameters. Its effect was more significant in previously injured lungs.

RESUMO Objetivo: Avaliar o efeito da atelectasia durante a ventilação mecânica nas regiões periatelectáticas e pulmonares normais em um modelo de atelectasia em ratos com lesão pulmonar aguda induzida por lipopolissacarídeo. Métodos: Foram distribuídos aleatoriamente 24 ratos em quatro grupos, cada um com 6 animais: Grupo Salina-Controle, Grupo Lipopolissacarídeo-Controle, Grupo Salina-Atelectasia e Grupo Lipopolissacarídeo-Atelectasia. A lesão pulmonar aguda foi induzida por injeção intraperitoneal de lipopolissacarídeo. Após 24 horas, a atelectasia foi induzida por bloqueio brônquico. Os animais foram submetidos à ventilação mecânica por 2 horas com parâmetros ventilatórios protetores, e a mecânica respiratória foi monitorada durante esse período. Em seguida, foram realizadas análises histológicas de duas regiões de interesse: as áreas periatelectásicas e o pulmão normalmente aerado contralateral às áreas atelectásicas. Resultados: O escore de lesão pulmonar foi significativamente maior no Grupo Controle-Lipopolissacarídeo (0,41 ± 0,13) do que no Grupo Controle-Solução Salina (0,15 ± 0,51), com p < 0,05. As regiões periatelectásicas apresentaram escores maiores de lesão pulmonar do que as regiões normalmente aeradas nos Grupos Atelectasia-Solução Salina (0,44 ± 0,06 versus 0,27 ± 0,74, p < 0,05) e Atelectasia-Lipopolissacarídeo (0,56 ± 0,09 versus 0,35 ± 0,04, p < 0,05). O escore de lesão pulmonar nas regiões periatelectásicas foi maior no Grupo Atelectasia-Lipopolissacarídeo (0,56 ± 0,09) do que na região periatelectásica do Grupo Atelectasia-Solução Salina (0,44 ± 0,06), p < 0,05. Conclusão: A atelectasia pode causar lesão no tecido circundante após um período de ventilação mecânica com parâmetros ventilatórios protetores. Seu efeito foi mais significativo em pulmões previamente lesionados.

RESUMO

Objective Testing an experimental model for ischemic necrosis of the femoral head in Legg-Calvé-Perthes disease by evaluating gait, imaging and morphohistology. Methods The operation was done in 11 piglets. Necrosis by cerclage in the right femoral neck was induced. Piglets were divided into group A, with 8 animals, euthanizing two in the 2 nd , 4 th , 6 th , and 8 th weeks, respectively; and group B, with 2 animals ( sham ), submitted to the surgical procedure without cerclage of the right femoral neck. The gait classification used was that of Etterlin. The frozen femurs were submitted to digital radiography and computed tomography. The height and width of the epiphysis and epiphysary coefficient were measured at study times. Light microscopy and immunohistochemistry with TGF-ß1 were performed. Results One animal died of sepsis in Group A. In this group, claudication was observed in all animals. On digital radiography and computed tomography, bone sclerosis, enlargement of the right femoral neck, flattening, collapse, and fragmentation of the right femoral head were observed. All epiphysis height and epiphysary coefficient values of the right femoral head were lower than the contralateral ones, in which were observed chondrocytes disordered and separated by gaps. A reduction in TGF-ß1 expression was observed at 2 and 6 weeks in the right femoral head and at eight in the left. In group B, there were no signs of necrosis and gait was normal. Conclusions The model presented reproduced macroscopic necrosis on digital radiography, computed tomography, and microscopy. Gait evaluation showed a good correlation with other ischemia findings. Level of Evidence V. Diagnostic studies.

RESUMO

Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208µm) than at four (186.9 ± 70.21µm, p = 0.0002) and two weeks (252.2 ± 55.1µm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.

RESUMO

Abstract Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208μm) than at four (186.9 ± 70.21μm, p = 0.0002) and two weeks (252.2 ± 55.1μm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.

Resumo Objetivo Reproduzir em modelo animal a técnica cirúrgica de Masquelet utilizada no tratamento de defeitos ósseos críticos e analisar as características da membrana formada em torno do cimento ósseo. Métodos Um defeito crítico de 10mm foi realizado na diáfise femoral de 21 ratos Sprague-Dawley. Após a ressecção da porção central da diáfise o defeito foi estabilizado com fio de Kirschner introduzido pelo canal medular e com a interposição de espaçador de cimento ósseo. Após 2, 4, e 6 semanas do procedimento cirúrgico os animais foram eutanasiados e avaliados em radiografias do membro posterior quanto ao tamanho do defeito, o alinhamento e a estabilidade da osteossíntese. As membranas formadas em torno do espaçador foram submetidas a análise histológica para avaliação da espessura, da maturação do tecido conjuntivo e da densidade vascular. Resultados Ao longo do tempo as membranas inicialmente constituídas por tecido conjuntivo frouxo foram substituídas por membranas representadas por tecido conjuntivo denso, rico em fibras colágenas espessas. Com seis semanas a espessura das membranas foi maior (565 ± 208μm) do que com quatro (186,9 ± 70,21μm, p = 0,0002) e duas semanas (252,2 ± 55,1μm, p = 0,001). Todas as membranas do tempo inicial apresentaram focos de diferenciação osteogênica que reduziram progressivamente ao longo do tempo. Conclusão Além da função estrutural e protetora da membrana, suas características biológicas intrínsecas podem contribuir ativamente para a regeneração óssea. A atividade biológica atribuída pela presença de focos de osteogênese confere à membrana potencial de osteoindução que favorece as condições locais para a integração do enxerto ósseo.

Assuntos

RESUMO

Abstract Objective Testing an experimental model for ischemic necrosis of the femoral head in Legg-Calvé-Perthes disease by evaluating gait, imaging and morphohistology. Methods The operation was done in 11 piglets. Necrosis by cerclage in the right femoral neck was induced. Piglets were divided into group A, with 8 animals, euthanizing two in the 2nd, 4th, 6th, and 8th weeks, respectively; and group B, with 2 animals (sham), submitted to the surgical procedure without cerclage of the right femoral neck. The gait classification used was that of Etterlin. The frozen femurs were submitted to digital radiography and computed tomography. The height and width of the epiphysis and epiphysary coefficient were measured at study times. Light microscopy and immunohistochemistry with TGF-β1 were performed. Results One animal died of sepsis in Group A. In this group, claudication was observed in all animals. On digital radiography and computed tomography, bone sclerosis, enlargement of the right femoral neck, flattening, collapse, and fragmentation of the right femoral head were observed. All epiphysis height and epiphysary coefficient values of the right femoral head were lower than the contralateral ones, in which were observed chondrocytes disordered and separated by gaps. A reduction in TGF-β1 expression was observed at 2 and 6 weeks in the right femoral head and at eight in the left. In group B, there were no signs of necrosis and gait was normal. Conclusions The model presented reproduced macroscopic necrosis on digital radiography, computed tomography, and microscopy. Gait evaluation showed a good correlation with other ischemia findings. Level of EvidenceV. Diagnostic studies.

Resumo Objetivo Testar um modelo experimental para necrose isquêmica da cabeça femoral na doença de Legg-Calvé-Perthes avaliando a marcha, exames de imagens e morfohistologia. Métodos Operaram-se 11 leitões. Induziu-se a necrose por cerclagem no colo femoral direito. Dividiram-se os leitões em grupo A com 8 animais, sacrificando-se dois na 2ª, 4ª, 6ª e 8ª semanas, respectivamente; e grupo B, com 2 animais (sham), submetidos ao procedimento cirúrgico sem a cerclagem do colo femoral direito. A classificação da marcha utilizada foi a de Etterlin. Os fêmures congelados foram submetidos à radiografia digital e tomografia computadorizada. Mediram-se a altura e largura da epífise e o coeficiente epifisário nos tempos de estudo. Realizou-se, microscopia de luz e imunohistoquímica com TGF-β1. Resultados Um animal morreu por sepse no grupo A. Neste grupo, observou-se claudicação em todos os animais. Na radiografia digital e tomografia computadorizada observaram-se: esclerose óssea, alargamento do colo femoral direito, achatamento, colapso e fragmentação da cabeça femoral direita. Todos os valores da altura da epífise e coeficiente epifisário da cabeça femoral direita foram menores que os contralaterais, nos quais observaram-se condrócitos desordenados e separados por lacunas. Observou-se redução da expressão do TGF-β1 com 2 e 6 semanas nas cabeças femorais direitas e nas esquerdas com oito. No grupo B, não ocorreram sinais de necrose e a marcha foi normal. Conclusões O modelo apresentado reproduziu a necrose macroscopicamente, na radiografia digital, tomografia computadorizada e microscopia. A avaliação da marcha demonstrou boa correlação com os demais achados de isquemia. Nível de EvidênciaV. Estudos diagnósticos.

Assuntos

RESUMO

Abstract Hepatic encephalopathy (HE) is a potentially reversible neuropsychiatric syndrome. Often, HE causes cognitive and motor dysfunctions due to an acute or chronic insufficiency of the liver or a shunting between the hepatic portal vein and systemic vasculature. Liver damage induces peripheral changes, such as in the metabolism and peripheral inflammatory responses that trigger exacerbated neuroinflammation. In experimental models, anti-inflammatory strategies have demonstrated neuroprotective effects, leading to a reduction in HE-related cognitive and motor impairments. In this scenario, a growing body of evidence has shown that peripheral and central nervous system inflammation are promising preclinical targets. In this review, we performed an overview of FDA-approved drugs and natural compounds which are used in the treatment of other neurological and nonneurological diseases that have played a neuroprotective role in experimental HE, at least in part, through anti-inflammatory mechanisms. Despite the exciting results from animal models, the available data should be critically interpreted, highlighting the importance of translating the findings for clinical essays.

Resumo A encefalopatia hepática (EH) é uma síndrome neuropsiquiátrica potencialmente reversível. Muitas vezes a EH causa disfunções cognitivas e motoras devido à insuficiência do fígado ou por um desvio entre a veia porta hepática e a vasculatura sistêmica. O dano no fígado provoca alterações periféricas, como no metabolismo e nas respostas inflamatórias periféricas, que desencadeiam uma neuroinflamação exacerbada. Em modelos experimentais, estratégias anti-inflamatórias têm demonstrado efeitos neuroprotetores, levando a uma redução dos prejuízos cognitivos e motores relacionados à EH. Neste cenário, evidências crescentes têm mostrado a inflamação periférica e no sistema nervoso central como um promissor alvo pré-clínico. Nesta revisão, abordamos uma visão geral de drogas e compostos naturais aprovados pelo FDA para o uso no tratamento de outras doenças neurológicas e não neurológicas, que tiveram papel neuroprotetor na EH experimental, pelo menos em parte, através de mecanismos anti-inflamatórios. Apesar dos resultados empolgantes em modelos animais, os dados avaliados devem ser criticamente interpretados, destacando a importância da tradução dos achados para ensaios clínicos.

RESUMO

The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.

RESUMO

Las Ciencias Médicas y Biológicas requieren, prioritariamente, que la investigación y la experimentación sean desarrolladas sobre organismos completos (los modelos animales). Su utilización ha permitido desarrollar innumerables ensayos preclínicos para evaluar los mecanismos patógenos y terapéuticos de diversas enfermedades, así como el estudio de las causas, naturaleza y cura de múltiples desórdenes de la salud humana. En este trabajo se muestra una panorámica general de los biomodelos de hipertensión arterial donde se describen: conceptos, características, origen, importancia, utilidad y procedimientos experimentales durante su fase de inducción. También se pondera la justificación de los biomodelos empleados en los estudios preclínicos de esta enfermedad. De igual forma, se describen los antecedentes para medir las alteraciones, las técnicas y los métodos directos e indirectos de medición de la presión arterial, la cual fue provocada experimentalmente en los animales de laboratorio para realizar los estudios de hipertensión humana.

Medical and biological sciences require, as a priority, that research and experimentation be carried out on complete organisms (animal models). Its use has allowed the development of innumerable preclinical tests to evaluate pathogenic and therapeutic mechanisms of various diseases, as well as to study the causes, nature and cure of multiple human health disorders. In this work, we show a general overview of arterial hypertension biomodels where concepts, characteristics, origin, importance, utility and experimental procedures during their induction phase are described. The justification of the biomodels used in preclinical studies of this disease is also considered. Antecedents are also described to measure alterations, techniques and direct and indirect methods of measurement of arterial pressure, which was provoked experimentally in the laboratory animals to carry out the studies of human hypertension.

Assuntos

RESUMO

Abstract The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.

Resumo A falha da reconstrução ligamentar tem diferentes fatores de risco, dentre os quais podemos destacar o período antes da sua incorporação, o qual configura um período mecânico vulnerável. A perda de resistência ao longo do tempo é uma característica dos tecidos vivos. A dissecção com as inserções ósseas dos ligamentos cruzados de modelos animais não é descrita; todavia, para os ensaios monoaxiais, é fundamental extrair as informações de ensaios como os de relaxação. O presente trabalho realiza a descrição da dissecção utilizada para a geração de corpo de prova para a realização de ensaios não destrutivos para avaliar o comportamento mecânico. Realizamos dissecção de quatro ligamentos de joelho porcino, propondo uma técnica de dissecção para os ligamentos cruzados com as inserções ósseas para comparação com os colaterais. Os ligamentos foram submetidos a testes de relaxação e foram colocadas strain gauges durante os testes. Os resultados mostraram comportamento viscoelástico, validado pelas strain gauges e com uma perda ao longo do tempo, sendo que, em alguns ligamentos, as perdas chegaram a até 20%, fator este a ser considerado em trabalhos futuros. O presente trabalho dissecou os quatro principais ligamentos do joelho, demonstrando a abordagem posterior que permite manter as suas inserções ósseas e descrevendo a fixação para os ensaios uniaxiais monotônicos, além de ter conseguido extrair o comportamento viscoelástico dos quatro ligamentos do joelho dentro dos limites fisiológicos do joelho.

Assuntos

RESUMO

To evaluate the osteoconductive potential of inorganic biomaterials of bovine origin submitted to different temperatures in the bone repair of critical defects in rat calvaria. Forty-eight rats were divided into four groups according to the material used to fill the defect: control group (GC), the defect was filled only with blood clot (n = 12); GBO, defect filled with Bio-Oss®, deproteinzed at 300°C (n = 12); GOX, defect filled with Inorganic GenOx®, deproteinzed from 850 to 1200°C (n = 12) and G700, defect filled with Inorganic GenOx 700, deproteinzed at 700°C (n = 12). In each animal's calvaria, a trephine bur with 5 mm internal diameter was used to produce a 6 mm-diameter central defect. Gen Derm® resorbable bovine membrane was superimposed over all defects. Subsequently, animals were euthanized at 30 and 60 days after surgery. The pieces were sent for histological and histometric analysis to evaluate the following variables: bone neoformation, presence of biomaterial, mononuclear and polymorphonuclear leukocytes, presence of other tissues (granulation and medullary) and maturation of collagen fibers. The most representative group for bone neoformation was GC. At 30 days, there was a higher mean of mature bone tissue (75.8). At 60 days, there was no statistical difference between the GC (64.9), GBO (32.9), GOX (45.3), and G700 (26.6) groups. GBO presented the highest amount of biomaterial after 30 days (115.9) and 60 days (118.5). All bovine biomaterials were biocompatible and osteoconductive. GOX promoted the best bone repair of the studied materials.

Assuntos

RESUMO

ABSTRACT Objective: this research objective was to develop a new peritoneal adhesion animal model that would lead to adhesions formation in all operated animals, simple and reproducible, associated with maintenance the animal's health. Methods: eighteen adult male Wistar rats (Rattus norvegicus) were randomly distributed into three groups: Control Group (anatomical and clinical parameters), Sham Group (delicate manipulation of the stomach and exposure of the peritoneal cavity to ambient air) and Surgery Group (gastrotomy followed by gastrorrhaphy). The animals were analyzed and classificated macroscopically according to two adhesion classification models and differences between groups were considered significant when p<0.05. Results: the six animals in the control group had no peritoneal adhesions, three of the six animals in the sham group had focal peritoneal adhesions, and all animals in the surgery group (gastrotomy followed by gastrorraphy) had firm peritoneal adhesions. All adhesions found were macroscopically quantified and microscopically confirmed, without carrying out a microscopic classification of the adhesions. Conclusion: the new model developed of gastrotomy followed by gastrorrhaphy, proved to be safe and efficient to induce and study peritoneal adhesions.

RESUMO Objetivo: o objetivo deste estudo foi criar um novo modelo animal de indução de aderências peritoneais capaz de levar à formação de aderências em todos os animais operados, simples e reprodutível, associado a manutenção da saúde dos animais. Métodos: Dezoito ratos machos, adultos, da linhagem Wistar (Rattus norvegicus) foram distribuídos aleatoriamente em três grupos: Grupo Controle (parâmetro anatômico e clínico), Grupo Sham (manipulação delicada do estômago e exposição de cavidade peritoneal ao ar ambiente) e Grupo Cirurgia (gastrotomia seguida de gastrorrafia). Os animais foram submetidos à análise e classificação macroscópicas, seguindo dois modelos de classificação de aderências. As diferenças entre os grupos foram consideradas estatisticamente significantes se p<0,05. Resultados: os seis animais do grupo controle não apresentavam aderências peritoneais, três dos seis animais do grupo sham apresentavam aderências peritoneais focais e todos os seis animais do grupo cirurgia (gastrotomia seguida de gastrorrafia) apresentavam aderências peritoneais firmes. Todas as aderências encontradas foram quantificadas macroscopicamente e confirmadas microscopicamente, sem a realização de classificação microscópica das aderências. Conclusão: o novo modelo desenvolvido, de gastrotomia seguida de gastrorrafia, mostrou-se seguro e eficiente para induzir e estudar aderências peritoneais.

RESUMO

ABSTRACT Introduction: Athletes and fitness enthusiasts often suffer muscle injuries during their training. These injuries can worsen when not treated properly, generating an accumulation of severe tissue damage, preventing optimal physical performance, and impacting low immunity. Despite a large number of researches on muscle injuries, its vast majority is limited to the pathological perspective, and there are few studies related to the specific impact of the body sport muscle injury index. Objective: Analyze the body-specific indicators of sports injury to prevent further damage to its practitioners. Methods: Laser scanning confocal electron microscopy is the main observation tool in studying muscle injury in athletes. In further research, an experimental animal model was established. The test samples were 40 male rats over 12 weeks old, randomly divided into four groups, treadmill exercise, swimming at 8% of the weight, and other sports training items. Results: Through the comparative experiment of three indicators, it is found that muscle damage has a widespread impact on the whole body, particularly on blood serum indicators. The period of one hour after injury is considered to have the most impact. However, the symptoms subside after 24 hours. Conclusion: As the main observation tool in this experiment, the microscope showed its good prospect of application in the field of biomedicine. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: Atletas e entusiastas adeptos ao condicionamento físico frequentemente sofrem lesões musculares durante seus treinamentos. Essas lesões podem se agravar quando não tratadas adequadamente, gerando um acúmulo de danos teciduais graves, impedindo o desempenho físico ideal e impactando na baixa imunidade. Apesar do grande número de pesquisas sobre lesões musculares, sua vasta maioria é limitada à perspectiva patológica e há poucos estudos relacionados ao impacto específico do índice de lesão muscular esportivo corporal. Objetivo: Analisar os indicadores específicos corporais da lesão esportiva dedicados a evitar maiores danos em seus praticantes. Métodos: A microscopia eletrônica confocal de varredura a laser é a principal ferramenta de observação no estudo da lesão muscular em atletas. Nas pesquisas adicionais, um modelo animal experimental foi estabelecido. As amostras de teste eram 40 ratos machos com mais de 12 semanas de idade, divididos aleatoriamente em quatro grupos, incluiu-se o exercício em esteira, natação com 8% do peso e outros itens de treinamento esportivo. Resultados: Através da experiência comparativa de três indicadores, constata-se que o dano muscular tem um impacto generalizado sobre todo corpo, particularmente nos indicadores do soro sanguíneo. O período de uma hora após a lesão é considerado como o mais impactante. No entanto, os sintomas diminuem após 24 horas. Conclusão: Como principal ferramenta de observação neste experimento, o microscópio mostrou sua boa perspectiva de aplicação no campo da biomedicina. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

Resumen Introducción: Los deportistas y entusiastas del condicionamiento físico suelen sufrir lesiones musculares durante sus entrenamientos. Estas lesiones pueden empeorar cuando no se tratan adecuadamente, generando una acumulación de daños graves en los tejidos, impidiendo un rendimiento físico óptimo y repercutiendo en la baja inmunidad. A pesar del gran número de investigaciones sobre las lesiones musculares, su gran mayoría se limita a la perspectiva patológica y hay pocos estudios relacionados con el impacto específico del índice de lesiones musculares en el deporte corporal. Objetivo: Analizar los indicadores corporales específicos de las lesiones deportivas dedicadas a prevenir mayores daños a sus practicantes. Métodos: La microscopía electrónica confocal de barrido láser es la principal herramienta de observación en el estudio de las lesiones musculares en los atletas. En otras investigaciones, se estableció un modelo animal experimental. Las muestras de prueba fueron 40 ratas macho de más de 12 semanas de edad, divididas aleatoriamente en cuatro grupos, en los que se incluyó el ejercicio en cinta rodante, la natación con un 8% de peso y otros elementos de entrenamiento deportivo. Resultados: A través del experimento comparativo de tres indicadores, se comprueba que el daño muscular tiene un impacto generalizado en todo el organismo, especialmente en los indicadores del suero sanguíneo. El período de una hora después de la lesión se considera el más impactante. Sin embargo, los síntomas disminuyen después de 24 horas. Conclusión: Como principal herramienta de observación en este experimento, el microscopio mostró sus buenas perspectivas de aplicación en el campo de la biomedicina. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

RESUMO

Purpose: To evaluate local and systemic effects of 24-hour fasting in liver ischemia and reperfusion injury. Methods: Twenty-one adult male Wistar rats (330-390 g) were submitted to 60 minutes of hepatic ischemia followed by 24 hours of reperfusion. Before the day of the experiment, the animals fasted, but free access to water was allowed. Two groups were constituted: Control: non-fasted, that is, feeding ad libitum before surgical procedure; Fasting: rats underwent previous fasting of 24 hours. Hepatic ischemia was performed using vascular clamp in hepatic pedicle. At 24 hours after liver reperfusion, blood and tissue samples were collected. To analysis, liver lobes submitted to ischemia was identified as ischemic liver and paracaval non-ischemic lobes as non-ischemic liver. We evaluated: malondialdehyde levels, hepatocellular function (alanine aminotransferase, aspartate aminotransferase activities, and both ratio), cytokines (interleukins-6, -10, and tumor necrosis factor-alpha), hepatic ischemia and reperfusion injury (histology). Results: Malondialdehyde measured in non-ischemic and ischemic liver samples, hepatocellular function and cytokines were comparable between groups. Histological findings were distinct in three regions evaluated. Microvesicular steatosis was comparable between 24-hour fasting and non-fasted control groups in periportal region of hepatic lobe. In contrast, steatosis was more pronounced in zones 2 and 3 of ischemic liver samples of fasting compared to control groups. Conclusions: These data indicates that fasting does not protect, but it can be also detrimental to liver submitted to ischemia/reperfusion damage. At that time, using long fasting before liver surgery in the real world may be contraindicated.

Assuntos

RESUMO

Purpose: The aim of this study was to assess the effects of resistance and aerobic exercise on colorectal cancer (CRC) development in mice induced by azoxymethane (AOM) coupled with colitis. Methods: Forty animals induced with CRC were used, divided into five groups of eight animals each: sedentary; continuous aerobics; continuous anaerobic; aerobic PI; and anaerobic PI. AOM was administered to the animals in two doses of 10 mg/kg each over the course of two weeks, the first dose administered in the third week and the second administered in the fourth. For the colitis, three cycles of dextran sodium sulfate were administered for five days, separated by two weeks of water. The 14th week of the experiment saw the euthanasia, the removal of their colons, and the creation of microscopy slides for histological analysis. Results: Preneoplastic lesions developed in all five groups; there were no significant differences between them. However, in terms of inflammatory symptoms, mucosal ulceration was much more frequently in the exercise groups than in the sedentary group (p = 0.016). The number of polyps overall (p = 0.002), the distal region's polyp development (p = 0.003), and the proximal region's polyp development (p = 0.04) were all statistically different than sedentary group. Conclusions: The study discovered no significant difference in disease activity index scores between groups, but there was a significant difference in the number of polyps and the presence of mucosal ulceration in the colon.

Assuntos

RESUMO

ABSTRACT Objective This study verified the replication efficiency of the Rocio virus in a primary culture of mouse neural cells. Methods Mixed primary cultures (neurons/glia) obtained from the brains of newborn isogenic BALB/c mice were inoculated with Rocio virus on the 7 th day of culture, and the development of cytopathogenic effects was monitored. The infection was confirmed via immunocytochemistry (anti-ROCV), while viral replication was quantified in infected primary cultures. The titration method used depended on the infection period. Results Rocio virus efficiently infected primary cultured neural cells, with the highest viral titer causing cytopathic changes was observed at 2 days post infection. The virus-infected primary culture survived for up to 7 days post infection, and viral load quantitation showed viral replication kinetics compatible with the cell death kinetics of cultures. Conclusion The findings of this study suggest that mouse neural cell primary cultures support Rocio virus replication and could be used as an alternative system for studying Flavivirus infection in the central nervous system.