Name: Clinical Score and Motor Performance Evaluation of Mouse Induced with Experimental Autoimmune Encephalomyelitis
Uploaded: 2023-10-13T13:10:00
Description: Watch this Scientific Journal Video about Clinical Score and Motor Performance Evaluation of Mouse Induced with Experimental Autoimmune Encephalomyelitis at JoVE.com

clinical score and motor performance evaluation of mouse induced with experimental autoimmune encephalomyelitis

Indução e avaliação da encefalomielite autoimune experimental em camundongos

Multiple Sclerosis (MS) is a chronic autoimmune inflammatory disease affecting the central nervous system (CNS). It shows the presence of perivascular infiltration of inflammatory cells, demyelination, axonal loss, and gliosis1. Its etiology remains unknown, and its clinical aspects, radiographic, and pathological features suggest remarkable heterogeneity in the disease2.
Due to its unknown etiology and complexity, at present, no animal model recapitulates all the clinical and radiological features displayed in human MS3,4. However, various animal models are employed to study different aspects of MS3,4. In these models, disease initiation is typically extremely artificial, and the timeframe of the onset of clinical signs is different between humans and mice. For example, in humans, the pathophysiological processes underlying the disease are undetected for years before the onset of clinical manifestations. Conversely, the experimenters can detect symptoms in animal models within weeks or even days after MS induction4.
Three basic animal models produce the features of demyelination that are characteristic of MS: those that are virus-induced (e.g., Theiler&#39;s murine encephalomyelitis virus), those that are induced by toxic agents (e.g., cuprizone, lysolecithin), and the different variants of experimental autoimmune encephalomyelitis (EAE)5. Each model helps study some specific facets of the disease but none replicates all the features of MS6. Thus, it is critical to choose the correct model considering the specific experimental needs and the scientific questions to be addressed.
Thanks to immunization procedures against myelin-derived antigens, EAE is induced by triggering an autoimmune response to CNS components in susceptible mice. The interplay between a wide range of immunopathological and neuropathological mechanisms causes the development of principal pathological traits of MS (i.e., inflammation, demyelination, axonal loss, and gliosis) in the immunized mice7,8. Mice begin to show clinical symptoms around the second week after immunization and generally show ascending paralysis from the tail to the limb and forelimb. The clinical score (i.e., quantification of the accumulation of disease-related deficits) is generally assessed using a 5-point scale7.
Active immunization with protein or peptide or passive transfer of encephalitogenic T cells can be used to induce EAE in mice with different genetic backgrounds (e.g., SJL/J, C57BL/6, and non-obese-diabetic (NOD) mice). Myelin proteolipid protein (PLP), myelin basic protein (MBP), and myelin oligodendrocyte glycoprotein (MOG) are examples of self-CNS proteins from which immunogens are usually produced. Particularly, SJL/J mice immunized with the immunodominant epitope of PLP (PLP139&#8722;151) develop a relapsing-remitting (RR) disease course, while C57BL/6J mice immunized with the immunodominant MOG35-55 peptide show EAE of a chronic nature1. Despite some limitations, such as providing very little information about MS progression, the role of B cells in the disease, the inside-out mechanisms, or difficulties in studying remyelination, the EAE models have hugely contributed to the understanding of autoimmune and neuroinflammatory processes, increasing the knowledge in the MS field and thus allowing the development of novel therapeutic approaches for this disease4,6.
In the present work, we focused on a particular form of active EAE, the myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55)-induced form9,10,11,12. The MOG35-55-induced EAE models a chronic form of MS. After immunization, the mice undergo an asymptomatic phase within the first week after immunization, then the disease typically arises during the second week after immunization, while between the third and fourth weeks after immunization, the disease becomes chronic, with no possibility of full recovery from the accumulated deficits7,8,13. Interestingly, no differences between males and females in incidence, disease onset, course, or progression are observed in most of the studies present in the literature14, even if fewer studies compare the disease in males and females.
In contrast, in humans, these parameters are known to be strongly sexually dimorphic2. MS affects more women than men; however, men generally develop a more aggressive form of the disease2. This evidence has suggested an essential, as well as complex, role of the gonadal hormones15; nevertheless, the role and the mechanism of action of sex hormones in the pathology remain unclear. Moreover, data from animal models support the idea that both estrogens and androgens exert positive effects on different tracts of the pathology in a sex-specific manner16,17.
Some studies also suggest neuroprotective, promyelinating, and anti-inflammatory effects of progesterone18 and, although evidence in MS patients is scarce18, neuroactive steroids (i.e., de novo synthetized steroids by the nervous system, such as pregnenolone, tetrahydroprogesterone, and dihydroprogesterone) might also affect the pathological course19. Collectively, these data support the idea that sex hormones produced both peripherally and inside the CNS have an important and sex-specific role in disease onset and progression. Therefore, in the present work, we urge the collection of separate data from both male and female animals.
From the histopathological point of view, the white matter of the spinal cord serves as the principal site of CNS injury in this model, which is characterized by multifocal, confluent regions of mononuclear inflammatory infiltration and demyelination8. Thus, in describing this protocol for the induction of MOG35-55-induced EAE in C57BL/6J mice, we will take into account the disease outcome in the two sexes and provide some histopathological insights regarding the spinal cords.

Autor em destaque: Criando um modelo experimental versátil de encefalomielite autoimune relevante para camundongos machos e fêmeas 

Modelagem da Esclerose Múltipla em Dois Sexos: Encefalomielite Autoimune Experimental Induzida por MOG35-55

Our research focuses on the experimental autoimmune encephalomyelitis, or EAE model, which can significantly announce the understanding of peripheral immune-mediated mechanism and evaluate neuroinflammatory and partially delineating processes. This model has also been widely used to develop and test a wide range of therapeutics drugs. Due to the unknown etiology and complexity of multiple sclerosis, no animal model currently recapitulates all the clinical and radiological features displayed in humans.Thus, it is quite challenging for the researchers to select the animal model most fitting for a specific experimental question. EAE is a widely used model of multiple sclerosis. However, to do several issue, only some studies performing this model considered both sexes.With our protocol, we want a light possibility of including both sexes in the study conducted in this model. Specifically, our protocol proposed a clinical evaluation based of two methods:the clinical score assessment and the rotator test, leading a more quantitative, less subjective and more precise clinical assessment of the disease course. Even though this model does not entirely reproduce the sexual dimorphism of multiple sclerosis, it has potential advantages.The combination of the induction with other possible risk factor, especially the environmental ones, can end in understanding specific effects of such factors and identifying the specific role in some sexually dimorphic aspect of the disease.

Watch this Scientific Journal Video about Clinical Score and Motor Performance Evaluation of Mouse Induced with Experimental Autoimmune Encephalomyelitis at JoVE.com

Clinical Score and Motor Performance Evaluation of Mouse Induced with Experimental Autoimmune Encephalomyelitis  

Avaliação do Escore Clínico e do Desempenho Motor de Camundongos Induzidos por Encefalomielite Autoimune Experimental

Depois de induzir a encefalomielite autoimune experimental no camundongo, peça a um investigador cego que realize a avaliação diária dos escores clínicos do animal. Pontuar cada animal em uma escala de 0 a 5 para avaliar a progressão da doença. Para avaliar o desempenho motor, inicie sessões de Rotor-Rod para os camundongos diariamente, começando em 1 DPI até que o estudo exija.Realizar cada sessão por 300 segundos, durante os quais, aumentar linearmente a velocidade de rotação da haste de 4 para 40 rotações por minuto. Quando o animal perde o equilíbrio e cai do dispositivo Rotor-Rod, ele pousa no chão acionando um sensor que registra o tempo. Registre o desempenho do animal e pontue-o como uma latência para cair.Um aumento significativo no escore clínico ou EC com o tempo foi observado em camundongos machos e fêmeas, a partir de 10 DPI até o desfecho. As fêmeas apresentaram maior CS do que os machos, mas não significativamente. Uma tendência ao início mais precoce da doença também foi observada no sexo feminino em comparação com o masculino.Além disso, as fêmeas apresentaram um EC cumulativo significativamente maior em comparação com os machos. Uma diminuição significativa no desempenho do rotor-haste com o tempo foi observada em camundongos machos e fêmeas. Particularmente, os homens apresentaram desempenho mínimo aos 16 DPI, enquanto as mulheres aos 17 DPI.Os homens tiveram melhor desempenho do que as mulheres, especialmente durante a fase crônica da doença, provavelmente como consequência da menor SC.

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