Ratos com baixo peso ao nascer apresentam maior suscetibilidade à infecção em modelo de sepse
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Data
2019
Autores
Azevedo, Gabriela Araujo de [UNIFESP]
Orientadores
Landgraf, Richardt Gama [UNIFESP]
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
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Resumo
A desnutrição intrauterina pode causar adaptações morfológicas e metabólicas
fetais, deixando este indivíduo mais propenso ao desenvolvimento de doenças
metabólicas, como diabetes e hipertensão na vida adulta. Os distúrbios metabólicos
também podem ser causados pelo desequilíbrio das respostas pró e anti-inflamatórias
no organismo, semelhante ao que observamos na sepse. Em estudos anteriores, nosso
grupo demonstrou que a desnutrição intrauterina global resultou em baixo peso ao
nascer, hipocelularidade na medula óssea e no sangue periférico, redução na migração
de leucócitos e uma menor resposta inflamatória em ratos Wistar com 12 semanas. O
objetivo deste estudo foi correlacionar se a menor resposta inflamatória pulmonar
aguda observada em ratos desnutridos intrauterinamente poderia significar uma maior
propensão ao desenvolvimento de infecções nesses animais. Para isso, ratas Wistar
(12-16 semanas de idade) foram colocadas para acasalar e após confirmação da
presença de espermatozoides no esfregaço vaginal, foram divididas em dois grupos:
G1 - alimentados com dieta e água ad libitum; G2 – sofreram restrição alimentar de
50% e água ad libitum. Os machos da prole G1 de peso normal ao nascer (PNN) e prole
G2 de baixo peso ao nascer (BPN) quando completados 12 semanas, foram
anestesiados e operados (Cecal Ligation and Pucture) ou falso operados, seis horas
após estimulo da sepse por meio do CLP estes ratos foram eutanasiados e os
parâmetros inflamatórios avaliados. Observamos hipotermia e hiperglicemia em
animais com sepse, além do aumento de creatinina e ureia no grupo sepse. As
citocinas IL-1β, IL-10, IL-6, IL-8, TNF-α e hormônio Leptina, tanto no soro quanto no
tecido pulmonar apresentaram aumento durante a sepse. Essas citocinas estão em
níveis mais elevados nos BPN com sepse do que no grupo PNN, com sepse. O lavado
broncoalveolar apresentou redução do infiltrado celular (células mononucleares) em
ambos os grupos com sepse. O lavado peritoneal apresentou um aumento no número
total de células nos grupos PNN e BPN quando induzida a sepse. A análise diferencial
das células mostrou que este aumento foi representado por células
polimorfonucleares (neutrófilos). Os animais do grupo BPN apresentaram um menor
número de células na medula óssea e este achado não foi alterado após a indução da
sepse. Mesmo com hipocelularidade na medula óssea nos animais BPN, o número de
células aumentou no lavado peritoneal, após 6 horas de CLP, assim como ocorrido no
grupo PNN. Logo, a hipocelularidade não comprometeu a migração de células efetoras,
como neutrófilos e macrófagos, para o foco da infecção, porém o número de unidade
formado de colônias no lavado peritoneal dos animais BPN com sepse foi maior do que
no grupo PNN sepse. Esses resultados indicam que ratos com baixo peso ao nascer,
induzidos por desnutrição intrauterina, são mais susceptíveis à infecção generalizada.
Intrauterine malnutrition can cause fetal morphological and metabolic adaptations, leaving this individual more prone to the development of metabolic diseases, such as diabetes and hypertension in adult life. Metabolic disturbances can also be caused by the imbalance of pro and anti-inflammatory responses in the body, similar to what we observed in sepsis. In previous studies, our group demonstrated that global intrauterine malnutrition resulted in low birth weight, hypocellularity in bone marrow and peripheral blood, reduction in leukocyte migration, and a lower inflammatory response in Wistar rats at 12 weeks. The aim of this study was to correlate whether the lower inflammatory response observed in malnourished rats intrauterinally could mean a greater propensity to develop infections in these animals. For this, Wistar rats (12-16 weeks of age) were placed to mate and after confirming the presence of spermatozoa in the vaginal smear, were divided into two groups: G1 - fed with diet and water ad libitum; G2 - undergo 50% food restriction and water ad libitum. Male offspring G1 of normal birth weight (NBW) and low birth weight G2 offspring (LBW) when completed 12 weeks were anesthetized and operated (Cecal Ligation Puncture) or false operated, six hours after sepsis stimulation by CLP (Cecal Ligation and Pucture) these rats were euthanized and the inflammatory parameters were evaluated. We then observed hypothermia and hyperglycemia in animals with sepsis, in addition to increased creatinine and urea in the sepsis group. The cytokines IL-1β, IL-10, IL-6, IL-8, TNF-α and hormone Leptin in both serum and lung tissue showed increased during sepsis. These cytokines are at higher levels in BPN with sepsis than in the PNN group, with sepsis. Bronchoalveolar lavage showed a reduction of the cellular infiltrate (mononuclear cells) in both groups with sepsis. The peritoneal lavage showed an increase in the total number of cells in the NBW and LBW groups when induced to sepsis. Differential analysis of the cells showed that this increase was represented by polymorphonuclear cells (neutrophils). The animals of the LBW group had a lower number of cells in the bone marrow and this finding was not altered after the induction of sepsis. Even with hypocellularity in the bone marrow in LBW animals, the number of cells increases in the peritoneal lavage, after 6 hours of CLP, as occurred in the NBW group. Thus, hypocellularity did not compromise the migration of effector cells, such as neutrophils and macrophages, to the focus of the infection, but the number of units formed of colonies in the peritoneal lavage of LBW animals with sepsis is greater than in the NBW sepsis group. Concluding, then, that rat with low birth weight, induced by intrauterine malnutrition, which impairs the development and differentiation of a normal immune system, compromises the body's response to sepsis.
Intrauterine malnutrition can cause fetal morphological and metabolic adaptations, leaving this individual more prone to the development of metabolic diseases, such as diabetes and hypertension in adult life. Metabolic disturbances can also be caused by the imbalance of pro and anti-inflammatory responses in the body, similar to what we observed in sepsis. In previous studies, our group demonstrated that global intrauterine malnutrition resulted in low birth weight, hypocellularity in bone marrow and peripheral blood, reduction in leukocyte migration, and a lower inflammatory response in Wistar rats at 12 weeks. The aim of this study was to correlate whether the lower inflammatory response observed in malnourished rats intrauterinally could mean a greater propensity to develop infections in these animals. For this, Wistar rats (12-16 weeks of age) were placed to mate and after confirming the presence of spermatozoa in the vaginal smear, were divided into two groups: G1 - fed with diet and water ad libitum; G2 - undergo 50% food restriction and water ad libitum. Male offspring G1 of normal birth weight (NBW) and low birth weight G2 offspring (LBW) when completed 12 weeks were anesthetized and operated (Cecal Ligation Puncture) or false operated, six hours after sepsis stimulation by CLP (Cecal Ligation and Pucture) these rats were euthanized and the inflammatory parameters were evaluated. We then observed hypothermia and hyperglycemia in animals with sepsis, in addition to increased creatinine and urea in the sepsis group. The cytokines IL-1β, IL-10, IL-6, IL-8, TNF-α and hormone Leptin in both serum and lung tissue showed increased during sepsis. These cytokines are at higher levels in BPN with sepsis than in the PNN group, with sepsis. Bronchoalveolar lavage showed a reduction of the cellular infiltrate (mononuclear cells) in both groups with sepsis. The peritoneal lavage showed an increase in the total number of cells in the NBW and LBW groups when induced to sepsis. Differential analysis of the cells showed that this increase was represented by polymorphonuclear cells (neutrophils). The animals of the LBW group had a lower number of cells in the bone marrow and this finding was not altered after the induction of sepsis. Even with hypocellularity in the bone marrow in LBW animals, the number of cells increases in the peritoneal lavage, after 6 hours of CLP, as occurred in the NBW group. Thus, hypocellularity did not compromise the migration of effector cells, such as neutrophils and macrophages, to the focus of the infection, but the number of units formed of colonies in the peritoneal lavage of LBW animals with sepsis is greater than in the NBW sepsis group. Concluding, then, that rat with low birth weight, induced by intrauterine malnutrition, which impairs the development and differentiation of a normal immune system, compromises the body's response to sepsis.