Efeito da desnutrição protéico-calórica experimental na resposta imune e na susceptibilidade á infecção por Staphylococcus aureus
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Data
2009-02-27
Autores
França, Thaís Graziela Donega [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A desnutrição diminui a eficácia da resposta imune aumentando a susceptibilidade aos agentes infecciosos. 0 principal tipo de deficiência nutricional e a desnutrição proteico-calórica (DPC). A restrição alimentar experimental e utilizada como modelo de estudo para a DPC. Neste contexto, os objetivos principais deste trabalho foram caracterizar urn modelo murino de DPC e avaliar seu efeito na susceptibilidade e na imunidade protetora ao Staphylococcus aureus. Foram testados três percentuais de restrição alimentar (10, 20 e 30%) em camundongos BALB/c e a restrição de 20% determinou as seguintes alterações as quais são condizentes com um estado de subnutrição: queda significativa de peso corporal e número de linfócitos, alteração na produção de citocinas e atrofia no timo e epitélio intestinal. A comparação do grau de susceptibilidade e da capacidade de montar uma resposta imune protetora ao S. aureus foi realizada atraves de duas metodologias: determinação do numero de unidades formadoras de colônias (UFC) em alguns órgãos e análise histopatológica do tecido pulmonar. Os resultados foram distintos dependendo da metodologia empregada. Quanto a susceptibilidade ao patógeno, a técnica de UFC indicou susceptibilidade similar nos grupos normal e subnutrido, enquanto que a análise histopatológica indicou maior quantidade de bactérias no pulmão dos animais normais. 0 processo de imunização controlou eficazmente a multiplicação bacteriana no pulmão dos animais normais, mas nao dos animais subnutridos. A análise histopatológica também mostrou perfis inflamatórios distintos nestes 2 grupos: camundongos normais apresentaram inflamação pulmonar só após infecção com S. aureus, como esperado, e a imunização prévia com antígenos de S. aureus preveniu esta inflamação. Por outro lado, camundongos subnutridos ja apresentavam inflamação pulmonar antes...
Undernutriton is one of the most relevant causes of secundary immunodeficiency. The main type of nutritional deficiency is called protein energy malnutrition (PEM). Animals submitted to different degrees of food restriction can be used as models of PEM. In this context, this work was done to establish a murine experimental model for PEM and to evaluate the effect of malnutrition on both, susceptibility and ability to mount a protective immunity against Staphylococcus aureus. BALB/c mice were therefore submitted to three distinct percentages of dietary re§triction (10, 20 and 30%). The 20% restricted diet determined the following alterations that characterize a state of malnutrition: a significant decrease in both, body weight and lymphocyte number, alteration in cytokine production and atrophy in thymus and intestinal epithelium. Two methodologies were used to compare susceptibility and ability to mount a protective immunity: determination of the number of colony forming units (CFU) in some organs and histopathological analysis of the lungs. Results varied according to the methodology. CFU indicated a similar susceptibility whereas the histopathological analysis showed a higher amount of bacterias in the lungs of normal mice. Immunization controlled bacterial growth in the lungs of normal mice but not in the ones from undernourished animals. Histopathological analysis also revealed distinct inflammatory scenarios: inflammation appeared in lungs from normal mice only after infection with S. aureus and immunization prevented lung inflammation in the animals. On the other hand, undernourished mice presented lung inflammation even before infection. In addition, the degree of this inflammatory process did not change with infection or previous immunization. Together, this data demonstrates that BALB/c mIce submitted to 20% food restriction developed... (Complete abstract click electronic access below)
Undernutriton is one of the most relevant causes of secundary immunodeficiency. The main type of nutritional deficiency is called protein energy malnutrition (PEM). Animals submitted to different degrees of food restriction can be used as models of PEM. In this context, this work was done to establish a murine experimental model for PEM and to evaluate the effect of malnutrition on both, susceptibility and ability to mount a protective immunity against Staphylococcus aureus. BALB/c mice were therefore submitted to three distinct percentages of dietary re§triction (10, 20 and 30%). The 20% restricted diet determined the following alterations that characterize a state of malnutrition: a significant decrease in both, body weight and lymphocyte number, alteration in cytokine production and atrophy in thymus and intestinal epithelium. Two methodologies were used to compare susceptibility and ability to mount a protective immunity: determination of the number of colony forming units (CFU) in some organs and histopathological analysis of the lungs. Results varied according to the methodology. CFU indicated a similar susceptibility whereas the histopathological analysis showed a higher amount of bacterias in the lungs of normal mice. Immunization controlled bacterial growth in the lungs of normal mice but not in the ones from undernourished animals. Histopathological analysis also revealed distinct inflammatory scenarios: inflammation appeared in lungs from normal mice only after infection with S. aureus and immunization prevented lung inflammation in the animals. On the other hand, undernourished mice presented lung inflammation even before infection. In addition, the degree of this inflammatory process did not change with infection or previous immunization. Together, this data demonstrates that BALB/c mIce submitted to 20% food restriction developed... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Imunologia - Aspectos nutricionais - Estudos experimentais, Staphylococcus aureus, Resposta imune, Undernutrition, Infection, Staphylococcus aureus, Immune response
Como citar
FRANÇA, Thaís Graziela Donega. Efeito da desnutrição protéico-calórica experimental na resposta imune e na susceptibilidade á infecção por Staphylococcus aureus. 2009. 105 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2009.