Modelos pré-clínicos de câncer hepático / Preclinical models of liver câncer

ABSTRACT Background: This manuscript provides an overview of liver carcinogenesis in murine models of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Objective: A review through MEDLINE and EMBASE was performed to assess articles until August 2022. Methods: Search was conducted of the entire electronic databases and the keywords used was HCC, CCA, carcinogenesis, animal models and liver. Articles exclusion was based on the lack of close relation to the subject. Carcinogenesis models of HCC include HCC induced by senescence in transgenic animals, HCC diet-induced, HCC induced by chemotoxicagents, xenograft, oncogenes, and HCC in transgenic animals inoculated with B and C virus. The models of CCA include the use of dimethylnitrosamine (DMN), diethylnitrosamine (DEN), thioacetamide (TAA), and carbon tetrachloride (CCl4). CCA murine models may also be induced by: CCA cells, genetic manipulation, Smad4, PTEN and p53 knockout, xenograft, and DEN-left median bile duct ligation. Results: In this review, we described different murine models of carcinogenesis that reproduce the key points for HCC and CCA genesis allowing a better understanding of its genetic, physiopathological, and environmental abnormalities. Conclusion: Each model has its advantages, disadvantages, similarities, and differences with the corresponding human disease and should be chosen according to the specificity of the study. Ultimately, those models can also be used for testing new anticancer therapeutic approaches.

RESUMO Contexto: Este manuscrito fornece uma visão geral da carcinogênese hepática em modelos murinos de carcinoma hepatocelular (CHC) e colangiocarcinoma (CCA). Objetivo: Realizar uma revisão de artigos científicos até agosto de 2022 utilizando as bases de dados MEDLINE e EMBASE. Métodos: A busca foi realizada em todas as bases de dados eletrônicas e as palavras-chave usadas foram CHC, CCA, carcinogenesis, modelos animais e fígado. A exclusão dos artigos baseou-se na falta de estreita relação com o assunto. Os modelos de carcinogênese do CHC incluíram: CHC induzido por senescência em animais transgênicos, CHC induzido por dieta, CHC induzido por agentes quimiotóxicos, xenoenxerto, oncogenes e CHC em animais transgênicos inoculados com vírus B e C. Os modelos de CCA incluíram: o uso de dimetilnitrosamina (DMN), dietilnitrosamina (DEN), tioacetamida (TAA) e tetracloreto de carbono (CCl4). Os modelos murinos de CCA induzidos por incluir: células de CCA, manipulação genética, animais nocaute para Smad4, PTEN e p53, xenoenxerto e ligadura do ducto biliar mediano esquerdo. Resultados: Nesta revisão, descrevemos diferentes modelos murinos de carcinogênese que reproduzem os pontos-chave para a gênese do CHC e do CCA, permitindo uma melhor compreensão de suas anormalidades genéticas, fisiopatológicas e ambientais. Conclusão: Cada modelo tem suas vantagens, desvantagens, semelhanças e diferenças com a doença humana correspondente e deve ser escolhido de acordo com a especificidade do estudo. Em última análise, esses modelos também podem ser utilizados para testar novas abordagens terapêuticas anticancerígenas.

Impacto do treinamento físico no perfil inflamatório e redox renal no desenvolvimento de síndrome metabólica / Impact of exercise training on inflammatory and redox renal profiles in metabolic syndrome development

Objetivo: Investigar o efeito do treinamento físico aeróbio (TF) no perfil inflamatório e de estresse oxidativo renal em modelo experimental de desenvolvimento de síndrome metabólica (SM). Métodos: Ratos Wistar e espontaneamente hipertensos (SHR) distribuídos nos grupos: controle (C), hipertenso (H), hipertenso frutose (HF) e hipertenso frutose treinado (HFT). Os grupos HF e HFT foram submetidos à sobrecarga de frutose (10%, 60 dias) desde o desmame. O TF foi realizado em esteira por 60 dias (5dias/semana, 40-60% velocidade máxima do teste de esforço). Resultados: O TF promoveu redução de ânion superóxido, peróxido de hidrogênio e proteínas oxidadas comparado ao grupo HF. Além disso, o grupo HFT apresentou aumento de FRAP e nitritos comparado aos grupos H e HF. No perfil inflamatório, o TF proporcionou aumento de IL-10 e redução da razão TNFα/IL-10. Conclusão: Os resultados demostraram que o treinamento aeróbio atenuou o estresse oxidativo e favoreceu um perfil anti-inflamatório no tecido renal em um modelo de desenvolvimento de SM.

Objective: To investigate the effect of aerobic exercise training (ET) on renal inflammatory and oxidative stress profiles in an experimental model of metabolic syndrome (MS) development. Methods: Wistar and spontaneously hypertensive (SHR) rats were distributed into control (C), hypertensive (H), hypertensive fructose (HF) and trained hypertensive fructose (THF) groups. The HF and THF groups were submitted to fructose overload (10%, 60 days) since weaning. The ET was performed on a treadmill for 60 days (5 days/week, 40-60% maximum speed of the exercise test). Results: The ET promoted reduction in renal superoxide anion, hydrogen peroxide and oxidized proteins compared to the HF group. In addition, the THF group showed an increase in FRAP and in nitrites compared to the H and HF groups. In the inflammatory profile, ET provided an increase in IL-10 and a reduction in TNFα/IL-10 ratio. Conclusion: The results showed that aerobic training attenuated oxidative stress and favored an anti-inflammatory profile in renal tissue in a model of MS development.

Adicción al tabaco y adolescencia: riesgos psicobiológicos / Psychobiological risks of tobacco during adolescence. A narrative review

Resumen La investigación moderna, tanto en humanos como preclínica, que utiliza modelos animales indica que fumar durante la edad adolescente resulta en cambios cerebrales y psicológicos a corto y largo plazo en el fumador, así como en un aumento significativo en los riesgos de desarrollar adicción al tabaco durante la vida. Por lo tanto, en la presente revisión narrativa se describirán y profundizarán los hallazgos investigativos modernos de la psicobiología de la adolescencia y los efectos del tabaco en el desarrollo, con un énfasis particular en la comprensión de los efectos psicológicos y cerebrales del consumo de tabaco durante la adolescencia, tanto a corto como a largo plazo. Se considerarán de manera detallada los avances investigativos sobre la psicobiología de la adolescencia y sus riesgos en las adicciones desde los aspectos: conductual, cognitivo, reactividad al estrés y psicobiología. Sobre esta base, se revisará la investigación sobre la psicobiología de la adolescencia y la evidencia de vulnerabilidad a la adicción durante esta etapa. Al final, se abordarán los efectos del tabaco en el cerebro y conducta durante el desarrollo adolescente y vida posterior, ya que se ha encontrado evidencia relacionada con alteraciones cerebrales crónicas en los sistemas colinérgicos y regiones cerebrales asociadas con la dependencia de la nicotina. Se espera que la revisión y divulgación de esta información en el idioma español sea de valor para la comprensión de los problemas de vulnerabilidad y predisposiciones a la adicción al tabaco en el contexto de Latinoamérica.

Abstract Tobacco use and its harmful health-related problems have become one of the largest modern preventable public health issues. Current research strongly suggests that smoking during adolescence enhances addictive smoking behaviors during life, which can be related to adolescence as a critical ontogenetic period characterized by behaviors that can increase the probability of risk-related behaviors such as sensation and novelty seeking. Adolescent development is also a period of maturation of frontal and subcortical neural systems, brain changes that underlie higher impulsivity tendencies to promote adequate learning and adaptations necessary to succeed the novel challenges of the adult life, but those changes also enhance vulnerabilities to the addictive effects of drugs. Consistent with this, tobacco use affects brain development processes which underlie long-term psychobiological alterations and the enhanced risks for tobacco addiction during adult life. Thus, the present review describes current psychobiological approaches to understand general addiction processes and tobacco addiction, highlighting the behavioral and neural short-term effects of tobacco use during adolescence and its long-term effects during adulthood. Current research has advanced on four aspects for the understanding of both the psychobiology of adolescent development and the effects of drugs of abuse during this time. The first aspect is behavioral, as adolescence is related to important changes on motivational and emotional behaviors such as sensation seeking. Other important behavioral changes are social approach, a higher variety of opportunity for personal choices, and development of personal independence. Research on a second aspect has focused on cognition. A review of research is presented showing enhanced abilities during adolescence development for reading, abstract and logical thinking, and novel problem solving. Stress reactivity is the third aspect of reviewed psychobiological mechanisms. The stress biological system undergoes important changes during adolescence, including changes on stress-related hormones and neural architecture. An important issue is that exposure to early and/or chronic stressful circumstances during adolescence could be related to higher risk to the start and maintenance of addiction states, as suggested by research assessing the disruptive effects of stress on psychobiological homeostatic processes needed to maintain stable biological and emotional regulation. The fourth aspect is psychobiology. In this section research is reviewed related to the development of monoaminergic brain circuits underlying motivation, novelty-seeking, impulsivity, and addiction processes. Using as model the previous review integration, the effects of nicotine are discussed, the essential addictive component of tobacco, on the neurochemical systems underlying tobacco addiction. Following this, important research is introduced that describes psychobiological changes during adolescence and evidence of vulnerability to addiction during this life stage. Then, current research on both short-term and long-term effects of tobacco or nicotine administration during adolescence on the brain, behavior, and cognition is introduced. The current research advances and discussions on the psychobiology of addictions in general, and tobacco addiction in particular, have been possible to a large extent from the use of animal models and preclinical research, since animal models have become crucial to identify learning, motivational, emotional, and cognitive mechanisms that underlie addictive processes, and making possible to perform experimental procedures to discover the functioning and participation of biological components. One example of such components is the cholinergic system, which is activated by nicotine and is part of the neurochemical machinery on different brain areas important for both tobacco addiction and adolescence development such as the dorsal striatum, amygdala, ventral tegmental area, nucleus accumbens, prefrontal cortex, and hippocampus. The present review and research divulgation written in Spanish are expected to clarify modern research on addiction and encourage current scientific education on the vulnerabilities and predispositions for tobacco abuse in Latin-American countries.

New methodological approach for coagulation assays using chicken plasma intrinsic properties

Background: Sensitivity of classical coagulation assays by using mammalian plasmas to pro‐ and anticoagulant compounds includ ing venom or toxins occurs on a microscale level (micrograms). Al though it improves responses to agonists, recalcification triggers a relatively fast thrombin formation process. The Recalcification Time (RT) of factor XII- deficient Chicken Plasma (CP) is comparatively long (≥1800 seconds) when compared to human plasma or others. Our objective was to compare its sensitivity with that presented by human plasma samples to Unfractionated Heparin (UH), a pro totype anticoagulant compound, under similar conditions through rotational thromboelastometry. Methods: To find doses of UH sufficient enough to prolong the Clotting Time (CT) parameter of these activated plasmas to values within their normal RT ranges. Results: In total, 0.0065±0.0009 IU of UH (n=6) was detected in 260µL of CP samples, but only 0.125±0.012 IU of UH was sufficient to induce a similar effect in activated human plasma samples. Conclusion: The higher sensitivity of CP to anticoagulants could be useful for (a) detection of anticoagulant compounds in substanc es of unknown origin; (b) purification procedures of anticoagulant toxins from crude animal venoms and (c) determination of relative potencies of agonists and their selective antagonists such as phar maceutical agents, antivenoms or natural inhibitors of venom tox ins with a better result in kinetic clothing parameters

Immune responses and protection against Streptococcus pneumoniae elicited by recombinant Bordetella pertussis adenylate cyclase (CyaA) carrying fragments of pneumococcal surface protein A, PspA

Streptococcus pneumoniae is a common agent of important human diseases such as otitis media, pneumonia, meningitis and sepsis. Current available vaccines that target capsular polysaccharides induce protection against invasive disease and nasopharyngeal colonization in children, yet their efficacy is limited to the serotypes included in the formulations. The virulence factor Pneumococcal Surface Protein A (PspA) interacts with host immune system and helps the bacteria to evade phagocytosis. Due to its essential role in virulence, PspA is an important vaccine candidate. Here we have tested a delivery system based on the adenylate cyclase toxin of Bordetella pertussis (CyaA) to induce immune responses against PspA in mice. CyaA was engineered to express fragments of the N-terminal region of PspAs from clades 2 and 4 (A2 and A4) and the resulting proteins were used in immunization experiments in mice. The recombinant CyaA-A2 and CyaA-A4 proteins were able to induce high levels of anti-PspA antibodies that reacted with pneumococcal strains expressing either PspA2 or PspA4. Moreover, reactivity of the antibodies against pneumococcal strains that express PspAs from clades 3 and 5 (PspA3 and PspA5) was also observed. A formulation containing CyaA-A2 and CyaA-A4 was able to protect mice against invasive pneumococcal challenges with isolates that express PspA2, PspA4 or PspA5. Moreover, a CyaA-A2-A4 fusion protein induced antibodies at similar levels and with similar reactivity as the formulation containing both proteins, and protected mice against the invasive challenge. Our results indicate that CyaA-PspA proteins are good candidates to induce broad protection against pneumococcal isolates.

Mice placental ECM components may provide a three-dimensional placental microenvironment

Bioethical limitations impair deeper studies in human placental physiology, then most studies use human term placentas or murine models. To overcome these challenges, new models have been proposed to mimetize the placental three-dimensional microenvironment. The placental extracellular matrix plays an essential role in several processes, being a part of the establishment of materno-fetal interaction. Regarding these aspects, this study aimed to investigate term mice placental ECM components, highlighting its collagenous and non-collagenous content, and proposing a potential three-dimensional model to mimetize the placental microenvironment. For that, 18.5-day-old mice placenta, both control and decellularized (n = 3 per group) were analyzed on Orbitrap Fusion Lumos spectrometer (ThermoScientific) and LFQ intensity generated on MaxQuant software. Proteomic analysis identified 2317 proteins. Using ECM and cell junction-related ontologies, 118 (5.1%) proteins were filtered. Control and decellularized conditions had no significant differential expression on 76 (64.4%) ECM and cell junction-related proteins. Enriched ontologies in the cellular component domain were related to cell junction, collagen and lipoprotein particles, biological process domain, cell adhesion, vasculature, proteolysis, ECM organization, and molecular function. Enriched pathways were clustered in cell adhesion and invasion, and labyrinthine vasculature regulation. These preserved ECM proteins are responsible for tissue stiffness and could support cell anchoring, modeling a three-dimensional structure that may allow placental microenvironment reconstruction.

Feasible low bone density condition for assessing bioactivity in ex-in vivo and in vivo studies

Abstract Objective To choose a critical animal model for assessments of bone repair with implant installation by comparing senile rats (SENIL) to young ovariectomized rats (OXV). Methodology For the ex-in vivo study, the femurs were precursors for bone marrow mesenchymal stem cells. Cellular responses were performed, including cell viability, gene expression of osteoblastic markers, bone sialoprotein immunolocalization, alkaline phosphatase activity, and mineralized matrix formation. For the in vivo study, the animals received implants in the region of the bilateral tibial metaphysis for histometric, microtomography, reverse torque, and confocal microscopy. Results Cell viability showed that the SENIL group had lower growth than OVX. Gene expression showed more critical responses for the SENIL group (p<0.05). The alkaline phosphatase activity obtained a lower expression in the SENIL group, as for the mineralization nodules (p<0.05). The in vivo histological parameters and biomechanical analysis showed lower data for the SENIL group. The confocal microscopy indicated the presence of a fragile bone in the SENIL group. The microtomography was similar between the groups. The histometry of the SENIL group showed the lowest values (p<0.05). Conclusion In experimental studies with assessments of bone repair using implant installation, the senile model promotes the most critical bone condition, allowing a better investigation of the properties of biomaterials and topographic changes.

Therapeutic potential of Punica granatum in wound healing: An overview

SUMMARY Objective: This review aim to report the results of the most recent research and applications of different extracts of P. granatum in the in vivo wound healing process. Methods: For the survey of articles in literature, a search was conducted in the PubMed, Scopus, Science Direct and Science Citation Index Expanded (Web of Science) databases. Results: Punica granatum is a plant native to Iran and adjacent regions widely used worldwide as a food and medicinal source. Its healing property is closely linked to the presence of phenolic compounds, tannins and flavonoids, and its concentration in treatment formulations seems to be determinant for the acceleration of tissue repair, although few data on the standardization and stability of these formulations are available. Studies on experimental models were able to demonstrate the repair potential of P. granatum; however, human studies are still scarce. Conclusions: This contribution summarizes the use of P. granatum extracts in healing different types of lesions, emphasizing its effects on inflammatory, prolif-erative, and remodeling phases.

Objetivo: Relatar los resultados de investigaciones y aplicaciones más recientes de diferentes extractos de P. granatum en el proceso de cicatrización de heridas in vivo. Métodos: Para encuesta de artículos en la literatura, se realizó búsqueda en las bases de datos PubMed, Scopus, Science Direct y Science Citation Index Expanded (Web of Science). Resultados: Punica granatum es una planta originaria de Irán y regiones adyacentes, ampliamente utilizada en todo el mundo como fuente alimenticia y medicinal. Su propiedad cicatrizante está íntimamente ligada a la presencia de compuestos fenólicos, taninos y flavonoides, y su concentración en las formulaciones de tratamiento parece ser determinante para aceleración de la reparación tisular, aunque se dispone de pocos datos sobre estandarización y estabilidad de estas formulaciones. Estudios sobre modelos experimentales pudieron demostrar el potencial de reparación de P. granatum; sin embargo, los estudios en humanos aún son escasos. Conclusiones: Este aporte resume el uso de extractos de P. granatum en la curación de diferentes tipos de lesiones, enfatizándose sus efectos en las fases inflamatoria, proliferativa y remodeladora.

Objetivo: Relatar os resultados de pesquisas mais recentes e aplicações de diferentes extratos de P. granatum no processo de cicatrização in vivo. Métodos: Para levantamento de artigos na literatura, realizou-se busca nas bases de dados PubMed, Scopus, Science Direct e Science Citation Index Expanded (Web of Science). Resultados: Punica granatum é uma planta nativa do Irã e das regiões adjacentes, amplamente utilizada em todo o mundo como alimento e fonte medicinal. A propriedade cicatrizante está intimamente ligada à presença de compostos fenólicos, taninos e flavo-noides, cuja concentração nas formulações de tratamento parece ser determinante para aceleração do reparo tecidual, embora poucos dados sobre a padronização e estabilidade dessas formulações estejam disponíveis. Estudos em modelos experimentais foram capazes de demonstrar o potencial de reparo de P. granatum. No entanto, estudos em humanos ainda são escassos. Conclusões: Esta contribuição resume o uso de extratos de P. granatum na cicatrização de diferentes tipos de lesões, enfatizando os efeitos nas fases inflamatória, proliferativa e remodelação.

Experimental carcinogenesis with 7, 12-dimethylbenz(a)anthrazene (DMBA) and its inhibition with isothi-ocyanates / Carcinogénesis experimental con 7, 12-dimetilbenzantraceno (DMBA) y su inhibición con isitiocianatos

Introduction: DMBA is a chemical carcinogen that induces carcinomas within a few weeks of its application. We developed an experimental model of carcinogenesis induced by DMBA dissolved in 0,5% paraffin oil (DMBA-PO), verifying the inhibitory effect of the carcinogenicity of phenyl isothiocyanate (PhITC), phenethyl (PhnITC) and benzyl isothiocyanate (BITC). Material and Methods: For this, 88 hamsters were distributed into three groups: one exposed to DMBA-PO (Group 1, n=12), three subgroups (n=12) exposed to PhITC, PhnITC, BITC and DMBA-PO (Group 2, n=36) and four control subgroups (n=10) that were not exposed to the carcinogen in which PO (paraffin oil) and isothiocyanates were applied (Group 3, n=40). Results: The experiment had a duration of 20 weeks, at the end of which the inhibitory effect was established by comparing the lesions developed in the groups that received isothiocyanates with the group that was only treated with DMBA-PO. The carcinogenic effect of DMBA-PO is 100% (35 carcinomas) and the inhibitory effect was 0, whereas in the presence of isothiocyanates the carcinogenic effect decreases, with an inhibitory effect of 86% for BITC (5 carcinomas) and 74% for PhITC (9 carcinomas). Conclusion: The inhibitory effect for PhnITC is 80% in relation to invasive OSCC (1 carcinoma).

Introducción: El DMBA es un carcinógeno químico que induce carcinomas a las pocas semanas de su aplicación. Desarrollamos un modelo experimental de carcinogénesis inducida por DMBA disuelto en aceite de parafina al 0,5% (DMBA-Ap) comprobando el efecto inhibidor de la carcinogénesis de los isotiocianatos fenil (PhITC), fenetil (PhnITC) y bencil isotiocianato (BITC). Material y Métodos: Para ello, se distribuyeron 88 hámsteres en 3 grupos: uno expuesto al DMBA-Ap (Grupo 1, n=12), tres subgrupos (n=12) expuestos a PhITC, PhnITC, BITC y DMBA-Ap (Grupo 2, n=36) y cuatro subgrupos controles (n=10), no expuestos al carcinógeno en el que se aplicaron Ap e isotiocianatos (Grupo 3, n=40). Resultados:El experimento tuvo una duración de 20 semanas, al final de la cual se establece de forma comparativa el efecto inhibidor comparando las lesiones desarrolladas en los grupos que recibieron isotiocianatos con respecto al grupo tratado sólo con DMBA-Ap. El efecto carcinógeno del DMBA-Ap es del 100% (35 carcinomas) y el efecto inhibidor 0, mientras que en presencia de isotiocianatos el efecto carcinógeno disminuye, con un efecto inhibidor del 86% para BITC (5 carcinomas) y del 74% para el PhITC (9 carcinomas). Conclusión:El efecto inhibidor del PhnITC es del 80% en relación con el COCE invasivo (1 carcinoma).

Importantes aspectos da nutrição do Zebrafish (Danio rerio) em biotérios

Research carried out with animals has increasingly required the possibility of reproducing the experiments and comparing the results obtained, one of the factors of great importance and influence on the quality of research animals is nutrition. The nutrition of laboratory animals is very relevant when we consider that animals need a diet that meets all their requirements, taking into account that they are in a controlled environment and contained in limited spaces with access only to the diet offered. When in the wild, animals select what to feed on, thus having a varied diet that meets their nutritional needs. An even greater challenge arises when we approach the nutrition of Zebrafish (Danio rerio), as they have a wide possibility of food sources and, being an omnivorous fish, the food sources of this species are very vast and still have few commercial options for food defined formula feeds for research animals. In addition, there is also concern about the interference of this diet correlated with diseases and even the quality of the water where the animals live. This review aims to outline a current overview of Zebrafish nutrition and the need to define rations with a standardized formula in order to improve research results.

As pesquisas realizadas com animais têm requerido cada vez mais a possibilidade de reprodutibilidade dos experimentos e comparação dos resultados obtidos, um dos fatores de grande importância e influência na qualidade dos animais de pesquisa é a nutrição. A nutrição de animais de laboratório é muito relevante ao considerarmos que os animais precisam de uma dieta que supra todas suas exigências, levando em consideração que estes estão num ambiente controlado e contidos em espaços limitados com acesso apenas a dieta ofertada. Quando em vida livre, os animais selecionam com o que se alimentar tendo assim uma dieta variada e que supre suas necessidades nutricionais. Um desafio ainda maior se apresenta ao abordarmos a nutrição de Zebrafish (Danio rerio), pois apresentam uma possibilidade imensa de fontes de alimentos e se tratando de um peixe onívoro, as fontes de alimento dessa espécie é muito vasta e ainda apresenta poucas opções comerciais de rações de fórmula definida para animais de pesquisa. Além disso, existe também a preocupação com a interferência dessa dieta correlacionada a doenças e até mesmo a qualidade da água onde vivem os animais. Esta revisão tem como objetivo traçar um panorama atual sobre a nutrição do Zebrafish e a necessidade de definição de rações com fórmula padronizada visando melhoria dos resultados das pesquisas.

Incisional hernia repair in rats: description of the sublay technique under videomagnification system

Purpose: To describe the technique of sublay correction of incisional hernia in Wistar rats under videomagnification system. Methods: Five male rats of the species Rattus norvegicus, of the Wistar lineage, with body weight between 250­350 g and 60 days old were used. Incisional hernia was inducted in all animals. After that, the incisional hernia was immediately corrected by the sublay method. Results: There were no cases of recurrence of the incisional hernia after placement of the polypropylene mesh using the sublay technique. No postoperative complications were observed. Conclusions: The technique is suitable for execution in Wistar rats.

Animal models and SARS-CoV-2-induced pulmonary and neurological injuries

Laboratory animals are essential mainly for experiments aiming to study pathogenesis and evaluate antivirals and vaccines against emerging human infectious diseases. Preclinical studies of coronavirus disease 19 (COVID-19) pathogenesis have used several animal species as models: transgenic human ACE2 mice (K18 mice), inbred BALB/c or C57BL/6N mice, ferrets, minks, domestic cats and dogs, hamsters, and macaques. However, the choice of an animal model relies on several limitations. Besides the host susceptibility, the researcher's experience with animal model management and the correct interpretation of clinical and laboratory records are crucial to succeed in preclinical translational research. Here, we summarise pathological and clinical findings correlated with virological data and immunological changes observed from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) experimental infections using different well-established SARS-CoV-2 animal model species. This essay aims to critically evaluate the current state of animal model translation to clinical data, as described in the human SARS-CoV-2 infection.

Perspectiva bioética para México, España y Estados Unidos en los modelos in vivo de inducción de daño al ADN

En la actualidad, la investigación biomédica se ha centrado en el estudio de enfermedades como el cáncer, que causan un elevado índice de mortalidad. Existen diferentes modelos animales, empleados para generar diversos tipos de carcinogénesis; el daño directo al ADN es uno de los mecanismos más utilizados. Sin embargo, en la normatividad nacional e internacional vigente, no se señalan los aspectos bioéticos que se deben seguir para desarrollar un modelo experimental de daño al ADN. Además, no se realiza una correcta semejanza de la enfermedad. Debido a lo anterior, esta revisión analiza los avances en cuanto a normatividad que se han generado en diferentes países, comparando los estudios encontrados en Estados Unidos, México y España. La perspectiva a futuro es poder contar con guías de experimentación actualizadas, que permitan pautar las normas necesarias para el adecuado desarrollo de los modelos de investigación animal de daño al ADN y que cumplan con la regla de las 3R en la experimentación animal. Esta iniciativa se debe de realizar en conjunto entre la Organización Mundial de la Salud y los organismos especializados en manejo y cuidado de animales de laboratorio en los ámbitos nacional e internacional.

Currently, biomedical research has focused on the study of diseases such as cancer that causes a high mortality rate. Different animal models are used to generate different types of carcinogenesis; direct DNA damage is one of the most used mechanisms. However, current national and international regulations do not indicate the bioethical aspects that must be followed to develop an experimental model of DNA damage. In addition, they do not perform a correct resemblance of the disease. Due to the above, this review analyzes the advances in regulations generated in different countries, comparing the studies found in the United States, Mexico, and Spain. The future perspective is to be able to count on updated experimentation guidelines, which allow the establishment of the necessary norms for the adequate development of animal research models of DNA damage that comply with the 3R rule in animal experimentation. This initiative should be carried out jointly by the World Health Organization and organizations specialized in managing and caring laboratory animals at the national and international levels.

Na atualidade, a pesquisa biomédica vem se focando no estudo de doenças que causam um elevado índice de mortalidade, como o câncer. Existem diferentes modelos animais utilizados para gerar diversos tipos de carcinogêneses; o dano direto ao DNA é um dos mecanismos mais utilizados. Contudo, na legislação nacional e internacional vigente, não são sinalizados os aspectos bioéticos que devem ser seguidos para desenvolver um modelo experimental de dano ao DNA, além de não ser realizada uma correta semelhança da doença. Devido a isso, esta revisão analisa o avanço quanto à legislação que vem sendo gerada em diferentes países, comparando os estudos encontrados nos Estados Unidos, no México e na Espanha. A perspectiva para o futuro é poder contar com atualizadas, que permitam estabelecer as normas necessárias para desenvolver os modelos de pesquisa animal de dano ao DNA e que cumpram com a regra das 3R na experimentação animal. Essa iniciativa se deve realizar em conjunto entre a Organização Mundial da Saúde e as organizações especializadas na gestão e cuidado de animais de laboratório nos contextos nacional e internacional.

Nuocytes from mesenteric lymph node promote allergic responses in a mouse model / Nuócitos de linfonodo mesentérico promovem respostas alérgicas em um modelo de camundongo

Abstract Introduction: Nuocytes play an important role in Type 2 immunity. However, the contribution of ILC2s to allergic rhinitis remains to be clearly elucidated. Objective: To evaluate the role of nuocytes from mesenteric lymph node on allergic responses in mice. Methods: After intraperitoneal administration of interleukin IL-25 and IL-33 to wild-type and Il17br-/-Il1rl1-/- double-deficient mice, nuocytes were purified from the the nasal-associated lymphoid tissue and mesenteric lymph nodes. Then, we assessed productions of IL-5 and IL-13 in nuocytes' cultures. Finally, we adoptively transferred the mesenteric lymph node-derived nuocytes from wild-type and Il17br-/-Il1rl1-/- mice to the murine model of allergic rhinitis to evaluate their roles in nasal allergic responses. Results: We showed that nuocytes in the mesenteric lymph nodes of wild-type mice were upregulated after application of IL-25 and IL-33, and were induced to produce IL-5 and IL-13. Numbers of sneezing and nasal rubbing as well as eosinophils were all enhanced after the adoptive transfer of wild-type nuocytes. Concentrations of IL-5, IL-13, IL-25 and IL-33 in nasal lavage fluid of allergic mice were also increased. However, nuocytes fromIl17br-/-Il1rl1-/- mice did not increase sneezing and nasal rubbing and eosinophilia, and upregulate the above cytokines in the nasal lavage fluid. Conclusion: The findings demonstrate that nuocytes from the mesenteric lymph nodes of wildtype mice promote allergic responses in a mouse model.

Resumo Introdução: Os nuócitos desempenham um papel importante na imunidade do tipo 2. No entanto, a contribuição das interleucinas ILC2s na rinite alérgica ainda precisa ser elucidada. Objetivo: Avaliar o papel dos nuócitos de linfonodos mesentéricos nas respostas alérgicas em camundongos. Método: Após a administração intraperitoneal de interleucina (IL)-25 e IL-33 em camundongos do tipo selvagem e camundongos Il17br-/-Il1rl1-/- com deficiência dupla, os nuócitos foram purificados do tecido linfoide associado a mucosa nasal e linfonodos mesentéricos. Em seguida, avaliamos as produções de IL-5 e IL-13 em culturas de nuócitos. Finalmente, transferimos adotivamente os nuócitos derivados de linfonodos mesentéricos de camundongos do tipo selvagem e camundongos Il17br-/-Il1rl1-/- para o modelo murino de rinite alérgica para avaliar seu papel nas respostas alérgicas nasais. Resultados: Mostramos que os nuócitos nos linfonodos mesentéricos de camundongos do tipo selvagem estavam up-regulados após a aplicação de IL-25 e IL-33 e foram induzidos a produzir IL-5 e IL-13. Os espirros e friçcão nasal, bem como os eosinófilos, aumentaram após a transferência adotiva de nuócitos do tipo selvagem. As concentrações de IL-5, IL-13, IL-25 e IL-33 no líquido da lavagem nasal de camundongos alérgicos também estavam aumentadas. Entretanto, os nuócitos de camundongos Il17br-/-Il1rl1-/- não aumentaram os espirros e a friçcão nasal ou eosinofilia e up-regularam as citocinas acima no líquido de lavagem nasal. Conclusão: Os achados demonstram que os nuócitos dos linfonodos mesentéricos de camundongos selvagens promovem respostas alérgicas em um modelo de camundongo.

Factores asociados al fracaso de las terapias neuroprotectoras en fase clínica en modelos animales con isquemia cerebral / Factors associated with the failure of the neuroprotector therapies in the clinical phase of animal models with cerebral ischemia

Los accidentes cerebrovasculares se han mantenido, a nivel mundial, como la tercera causa de muerte y la primera de discapacidad. Para disminuir la incidencia de casos de isquemia o hemorragia cerebral, así como sus consecuencias, se deben poseer los conocimientos sobre dichas entidades clínicas, los factores de riesgo asociados y las alternativas preventivas y terapéuticas como estrategias neuroprotectoras. Muchas de las intervenciones médicas realizadas hasta la fecha en modelos animales han resultado insatisfactorias en la fase clínica. Por ello, se realizó una revisión de las publicaciones más recientes donde se abordan los modelos experimentales para la isquemia cerebral más utilizados en las evaluaciones de las terapias neuroprotectoras, y se pudo concluir que si se analizan los protocolos empleados en la fase preclínica podrán optimizarse las investigaciones para lograr resultados más acertados en este campo.

The strokes have been considered, worldwide, as the third cause of death and the first cause of disability. To diminish the incidence of ischemia cases or cerebral hemorrhage, as well as their consequences, one should have the knowledge on this clinical entities, the associated risk factors and preventive and therapeutic alternatives as neuroprotector strategies. Many of the medical interventions carried out so far in animal models have been unsatisfactory in the clinical phase. Reason why, a review of the most recent publications was carried out, where the most used experimental models for the cerebral ischemia in the evaluations of the neuroprotector therapies are approached, and it was concluded that if protocols used in the preclinic phase are analyzed, the investigations could be optimize to achieve more relevant results in this field.

Mus musculus: biomodelo de expresión de Desyodinasa (DIO3) y Transtiretina (TTR) en el desarrollo placentario / Mus musculus: an experimental model for Deiodinase (DIO3) and Transthyretin (TTR) expression during placental development / Mus musculus: Biomodelo de expressão de Deiodinase (DIO3) e Transtiretina (TTR) no desenvolvimento da placenta

RESUMEN Introducción: El correcto funcionamiento del eje hipotálamo-hipófisis-tiroides es indispensable para el crecimiento y desarrollo embrionario-fetal, al intervenir en la diferenciación de los tejidos, el desarrollo cerebral y somático, la maduración ósea y la regulación del metabolismo. El paso de las hormonas tiroideas maternas al feto a través de la placenta depende de transportadores transmembrana, enzimas desyodinasas (DIO2 y DIO3) y proteínas transportadoras (TTR). Objetivo: Identificar las zonas de expresión de DIO3 y TTR en la placenta de ratón Mus musculus E10.5, E12.5, E14.5. Métodos: La estructura placentaria y expresión de DIO3 y TTR fueron evaluadas con técnicas histoquímicas e inmunofluorescencia. Resultados: Desde E10.5 se encontraron las tres zonas placentarias, laberinto, zona de unión y decidua. En E12.5 se observó la conformación placentaria definitiva. DIO3 y TTR fueron detectadas en los tres estadios, con predominio en la zona del laberinto. Conclusión: DIO3 y TTR se expresan a lo largo del establecimiento y maduración de la placenta de ratón. El biomodelo murino es una herramienta útil para el estudio del transporte placentario de hormonas tiroideas desde la circulación materna a la fetal.

ABSTRACT Introduction: Correct functioning of hypothalamic-pituitary-thyroid axis is essential for embryonic-fetal growth and development, as it is involved in tissue differentiation, brain and somatic development, bone maturation and metabolic regulation. Maternal thyroid hormones passage to the fetus through the placenta depends on transmembrane transporters, deiodinase enzymes (DIO2 and DIO3) and carrier proteins (TTR). Objective: Identify DIO3 and TTR expression within placental layers of Mus musculus E10.5, E12.5 and E14.5. Methods: Placental structure, DIO3 and TTR expression were evaluated using histochemistry and immunofluorescence techniques. Results: We found that the three placental layers, labyrinth zone, junctional zone, and decidua were present since E10.5. At E12.5 placental final conformation was observed. DIO3 and TTR were detected in the three stages with a predominance in the labyrinth. Conclusion: DIO3 and TTR are expressed throughout the establishment and maturation of mouse placenta. Mice are a useful tool for studying how thyroid hormones are transported from maternal t° fetal circulation at the placenta.

RESUMO Introdução: O correto funcionamento do eixo hipotálamo-hipófise-tireoide é essencial para o crescimento e desenvolvimento embrionário-fetal, pois intervém na diferenciação dos tecidos, desenvolvimento cerebral e somático, maturação óssea e regulaçãodo metabolismo. A passagem dos hormônios tireoidianos maternos para o feto através da placenta depende de transportadores transmembranas, enzimas deiodinase (DIO2 e DIO3) e proteínas transportadoras (TTR). Objetivo: Identificar as zonas de expressão de DIO3 e TTR na placenta de rato Mus musculus E10.5, E12.5, E14.5. Métodos: A estrutura placentária e a expressão de DIO3 e TTR foram avaliadas com técnicas histoquímicas e imunofluorescência. Resultados: De E10.5 as três zonas placentárias, labirinto, zona de união e decídua foram encontradas. Em E12.5 a conformação definitiva da placenta foi observada. O DIO3 e o TTR foram detectados nas três fases, com predomínio na área do labirinto. Conclusão: DIO3 e TTR são expressos ao longo do estabelecimento e maturação da placenta de rato O biomodelo murino é uma ferramenta útil para o estudo do transporte placentário dos hormônios tireoidianos da circulação materna para a fetal.

Modeling of post-traumatic epilepsy and experimental research aimed at its prevention

Research on the prevention of post-traumatic epilepsy (PTE) has seen remarkable advances regarding its physiopathology in recent years. From the search for biomarkers that might be used to indicate individual susceptibility to the development of new animal models and the investigation of new drugs, a great deal of knowledge has been amassed. Various groups have concentrated efforts in generating new animal models of traumatic brain injury (TBI) in an attempt to provide the means to further produce knowledge on the subject. Here we forward the hypothesis that restricting the search of biomarkers and of new drugs to prevent PTE by using only a limited set of TBI models might hamper the understanding of this relevant and yet not preventable medical condition.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Standardization of an experimental model of intradural injection after spinal cord injury in rats

OBJECTIVES: The intrathecal route has not yet been thoroughly standardized and evaluated in an experimental model of spinal cord injury (SCI) in Wistar rats. The objective of this study was to standardize and evaluate the effect of intradural injection in this animal model. METHOD: The animals were divided into 6 groups: 1) laminectomy and intradural catheter; 2) laminectomy, intradural catheter and infusion; 3) only SCI; 4) SCI and intradural catheter; 5) SCI, intradural catheter and infusion; and 6) control (laminectomy only). Motor evaluations were performed using the Basso, Beattie and Bresnahan (BBB) scale and the horizontal ladder test; motor evoked potentials were measured for functional evaluation, and histological evaluation was performed as well. All experimental data underwent statistical analysis. RESULTS: Regarding motor evoked potentials, the groups with experimental SCI had worse results than those without, but neither dural puncture nor the injection of intrathecal solution aggravated the effects of isolated SCI. Regarding histology, adverse tissue effects were observed in animals with SCI. On average, the BBB scores had the same statistical behaviour as the horizontal ladder results, and at every evaluated timepoint, the groups without SCI presented scored significantly better than those with SCI (p<0.05). The difference in performance on motor tests between rats with and without experimental SCI persisted from the first to the last test. CONCLUSIONS: The present work standardizes the model of intradural injection in experimental SCI in rats. Intrathecal puncture and injection did not independently cause significant functional or histological changes.

New model of Oral Mucositis with 5-Fluorouracil chemo-induced in Wistar rats without the use of anesthesics / Novo modelo de Mucosite Oral quimioinduzida com 5-Fluorouracil em ratos Wistar sem uso de anestésicos

ABSTRACT Introduction: Oral mucositis (OM) is considered the most frequent acute side effect of the antineoplasic treatment, with ulcerative lesions resulting from a painful symptomatology, affecting the oral cavity in response to the Antineoplastic treatment. In order to study these side effects, experiments in animal models are necessary, using antineoplastic drugs for the induction of OM and anesthetics, mainly Ketamine and Xylazine, to perform scarification of the cheeks. Objective: The goal is to report an experimental model of induced OM, without the use of anesthetics for the scarification stage of the animal cheeks. Methods: Fourty five male Wistar rats, 7 weeks old and weighting 220g, were used, divided into 2 groups; with OM induced by 5-Fluorouracil intraperitoneal administration. Two days later, Group I was physically contained, in contrast, Group II were anesthetized with Ketamine and Xylazine, focusing on irritating the cheek mucosa using the tip of a sterile needle, in order to potentialize the development of OM. The animals were euthanized with an anesthetic overdose. Results: Concerning the experiment of 5-Fluorouracil chemo-induced of OM, where the irritation was performed by physical containment, without the use of anesthetics (Ketamine and Xylazine), the animals had a longer survivability and a rapid improvement of the side effects induced by chemotherapy. Conclusion: This new model is promising, considering that the use of anesthetics (Ketamine and Xylazine) showed a high mortality rate. In the absence of anesthesia, all the animals survived until the end of the experiment involving chemotherapy model with 5-Fluorouracil and physical restraint.

RESUMO Introdução: A mucosite oral (MO) é considerada o efeito colateral agudo mais frequente do tratamento antineoplásico, com lesões ulcerativas decorrentes de sintomatologia dolorosa, acometendo a cavidade oral em resposta ao tratamento antineoplásico. Para estudar esses efeitos colaterais, são necessários experimentos em modelos animais, utilizando fármacos antineoplásicas para a indução de MO e anestésicos, principalmente Cetamina e Xilazina, para realizar a escarificação das bochechas Objetivos: Relatar um novo modelo experimental de MO induzida, sem o uso de anestésicos, para a etapa de escarificação das bochechas dos animais. Métodos: Foram utilizados 45 ratos Wistar machos, com 7 semanas de idade e peso de 220g, divididos em 2 grupos com MO induzida pela administração intraperitoneal de 5-fluorouracil. Dois dias depois, o Grupo I foi contido fisicamente, ao contrário, o Grupo II foi anestesiado com Cetamina e Xilazina, com foco em irritar a mucosa da bochecha com a ponta de uma agulha estéril, a fim de potencializar o desenvolvimento de MO. Os animais foram eutanasiados com sobredose de anestésica. Resultados: Em relação ao experimento de 5-Fluorouracil quimioinduzido para MO, onde a irritação foi realizada por contenção física, sem o uso de anestésicos (Cetamina e Xilazina), os animais tiveram maior sobrevida e rápida melhora dos efeitos colaterais induzidos por quimioterapia. Conclusão: Este novo modelo é promissor, visto que o uso de anestésicos (Cetamina e Xilazina) apresentou elevada mortalidade. Porém, na ausência de anestesia, todos os animais sobreviveram até o final do experimento envolvendo este modelo de quimioterapia induzida com 5-fluorouracil e contenção física.