Proposta de um modelo murino de curta duração de resposta pulmonar alérgica aguda sem utilização de adjuvante / Proposed short-term model of acute allergic response, without adjuvant use, in the lungs of mice

OBJETIVO: Determinar se um protocolo curto de sensibilização com ovalbumina subcutânea, sem adjuvante, induziria uma resposta pulmonar eosinofílica em pulmões de camundongos similar àquela encontrada em protocolos previamente estabelecidos. MÉTODOS: Fêmeas adultas de camundongos BALB/c foram randomizadas e divididas em grupos de acordo com o número de sensibilizações com ovalbumina e o número/dosagem de provocação intranasal. O protocolo curto (10 dias) consistiu de uma sensibilização e três provocações com ovalbumina (100 µg). A contagem total e diferencial de células no lavado broncoalveolar, o nível de peroxidase eosinofílica no tecido pulmonar e o exame histopatológico dos pulmões foram realizados 24 h após a última provocação. RESULTADOS: Não houve diferenças significativas entre os grupos em relação às variáveis estudadas. O protocolo curto, assim como os outros protocolos estudados, induziu uma resposta eosinofílica pulmonar semelhante àquela do grupo controle positivo. CONCLUSÕES: A sensibilização por ovalbumina subcutânea sem o uso de adjuvante resultou em uma significativa resposta pulmonar alérgica em ratos, mesmo no grupo de protocolo curto. Nossos achados sugerem que esse protocolo curto pode ser utilizado como teste pré-clínico de primeira linha para a pesquisa de novos fármacos, reduzindo custos e o tempo de observação.

OBJECTIVE: To determine whether a short-term protocol using subcutaneous sensitization with ovalbumin, without the use of adjuvants, would induce an eosinophilic response in the lungs of mice similar to that observed in previous, well-established protocols. METHODS: Adult female BALB/c mice were randomized and divided into groups according to the number of sensitizations with ovalbumin and the number/dosage of intranasal ovalbumin challenges. The short-term protocol (10 days) consisted of one sensitization with ovalbumin and three ovalbumin challenges (100 µg). Total and differential cell counts in BAL fluid, levels of eosinophil peroxidase in lung tissue, and histopathological examination of the lungs were performed 24 h after the last ovalbumin challenge. RESULTS: No significant differences were found among the groups regarding the variables studied. The short-term protocol, as well as the other protocols studied, induced an eosinophilic response similar to that obtained in the positive control. CONCLUSIONS: Subcutaneous sensitization with ovalbumin and without the use of adjuvants resulted in a significant allergic response in the lungs of mice, even in the short-term protocol group. Our findings suggest that this short-term protocol can be used as a first-line pre-clinical test for the study of new medications, reducing the costs and observation periods.

Asma: a arte do encontro / Asthma: the art of meeting

A asma é um importante problema de Saúde Pública. Estima-se que ela comprometa cerca de 300 milhões de pessoas e mate 250 mil a cada ano, em todo o mundo. Trata-se de uma alteração inflamatória crônica das vias aéreas, cujas principais características incluem, também, grau variável de obstrução ao fluxo aéreo e hiper-responsividade brônquica. O tratamento é baseado em fármacos anti-inflamatórios e broncodilatadores. Para pacientes que permanecem sintomáticos vêm sendo desenvolvidas novas terapias, desenhadas para atingir alvos-chaves na patogenia.

Asthma is a serious health problem throughout the world. It is estimated that 300 million people are affected and 250 thousands are killed by asthma worldwide. Asthma is a multifactorial chronic inflammatory disorder of the airway in which the chief features include a variable degree of airflow obstruction and bronchial hyper-responsiveness, in addition to the underlying chronic airway inflammation. Asthma's treatment is based on anti-inflammatory and bronchodilator drugs. For patients who remain symptomatic new therapies tailored to target key pathways in asthma pathology are being developed.

Tos persistente / Presistent cough in children

La tos es un síntoma molesto, quizás más para los circunstantes que para quien la padece, es un reflejo protector del paciente y una voz de alerta para el médico, es el síntoma más frecuente en pediatría. El centro de la tos está situado en la parte superior del tallo cerebral y protuberancia, muy cerca del centro del vómito, lo que explica que con frecuencia la tos produzca éste

Emergence of T-lymphocytes, eosinophils and dendritic cells in the bronchi of actively sensitized guinea pigs after antigenic challenge

Bronchi from guinea pigs actively sensitized to ovalbumin and boosted two weeks later display increased numbers of CD4+ T-lymphocytes and eosinophils. We have further investigated immunopathological changes in sensitized guinea pigs 2 or 24 h after antigenic challenge with ovalbumin. Lungs were resected, frozen and cryostat sections stained with monoclonal antibodies that recognize relevant guinea pig epitopes. Cyanide-resistant peroxidase activity was used to stain eosinophils. No further increase in T-lymphocytes or eosinophils was observed 2 h after challenge. At 24 h, a marked increase in EPO+ eosinophils was found, and this was accompanied by severe mucosal damage characterized by epithelial shedding and ulceration. The numbers of T-lymphocytes remained stable but a novel population of cells with the appearance of dendritic cells was seen in the bronchial wall. They were negative for macrophage markers but were strongly Class II positive. These findings suggest that antigenic challenge results in further recruitment of eosinophils, their activation and release of toxic substances to the epithelium. Furthermore, other cell types, possibly dendritic cells, are attracted to the bronchi and could play a role in maintaining allergic inflammation via antigen presentation.