ABSTRACT
Early weaning predisposes the pig intestine to structural and functional alterations, due to the increase in E. coli populations. These bacteria use the lipopolysaccharide (LPS) derived from their cell wall as an important pathogenic factor. Little is known about the effects of LPS on the intestinal morphology. Such knowledge could be helpful in understanding the pathogenesis of post-weaning enteritis, which is needed to design therapeutic strategies. Objective: this study aimed to evaluate the effects of the oral intake of LPSon the morphology of intestinal villi and glands of weaned pigs. Methods: the study used 52 pigs weaned at 21 days. The animals were fed a basal diet added with four levels of LPS (0.0, 0.3, 0.5 and 1.0 µg/mg of food) for 10 days. Pigs were sequentially slaughtered on days 1, 5, 7 and 10 after weaning, and samples of small intestine were taken to evaluate morphological parameters by computerized image analysis. The statistical design used was randomized blocks in a 4x4 factorial arrangement. Results: results showed that LPS decreases the height and area of intestinal villi, and increases the width of the villi and the depth and width of the intestinal glands. These effects probably contribute to a decreased intestinal nutrient absorption and increase co-infection with other pathogens, thus leading to the post-weaning diarrhea syndrome. Conclusions: this study stresses the usefulness of computerized morphometric analysis to evaluate the effect of LPS on intestinal morphology, so it may be used in future studies to investigate the pathophysiology of the causative agents of enteritis and to evaluate therapeutic strategies.
El destete precoz de los cerdos predispone al desarrollo de alteraciones estructurales y funcionales en el intestino y a enteritis causadas por la bacteria Escherichia coli; la cual utiliza el LPS de su pared como uno de sus principales factores patogénicos. Debido a que se conoce poco sobre los efectos del LPS sobre los parámetros morfológicos intestinales, y a que ese conocimiento es necesario para comprender la patogenia de las enteritis postdestete y para diseñar estrategias terapéuticas. Objetivo: se realizó este estudio con el objetivo de evaluar el efecto de la administración de LPS de E. coli sobre la morfología de las vellosidades y las glándulas intestinales en cerdos recién destetados. Métodos: El estudio experimental se realizó con 52 cerdos destetados a los 21 días de edad. Los animales fueron alimentados con una dieta basal adicionada con cuatro niveles de LPS (0.0, 0.3, 0.5 y 1.0 µg/mg de alimento) durante 10 días. Los cerdos se sacrificaron escalonadamente los días 1, 5, 7 y 10 posdestete y se tomaron muestras de intestino delgado para determinar algunos parámetros morfológicos mediante análisis computarizado de imágenes. El diseño estadístico empleado fue bloques al azar en un arreglo factorial 4x4. Resultados: como resultados se obtuvo que el LPS disminuye la altura y el área de las vellosidades y aumenta su ancho, así como la profundidad y ancho de las glándulas intestinales. Estos efectos probablemente disminuyen la absorción intestinal de nutrientes, incrementan la co-infección con otros agentes patógenos y la presentación del síndrome de diarrea posdestete. Conclusiones: Este estudio muestra la utilidad del análisis morfométrico computarizado para evaluar el efecto del LPS sobre los parámetros morfológicos intestinales, por lo que podría utilizarse en futuros estudios para investigar la fisiopatología de los agentes causantes de enteritis y para evaluar estrategias terapéuticas.
O desmame precoce dos suínos predispõe o desenvolvimento de alterações estruturais e funcionais no intestino e à enterite causada pela bactéria Escherichia coli, que usa o LPS da parede como um dos principais fatores patogênicos. Devido a que pouco se sabe sobre os efeitos do LPS sobre os parâmetros morfológicos intestinais, e que esse conhecimento é necessário para compreender a patogênese da enterite pós-desmame e projetar estratégias terapéuticas. Objetivo: este estudo foi realizado para avaliar o efeito administração de LPS de E. coli sobre a morfologia das vilosidades e glândulas intestinais em suínos desmamados. Métodos: o estudo experimental foi realizado com 52 leitões desmamados aos 21 dias de idade. Os animais foram alimentados com uma dieta basal suplementada com quatro níveis de LPS (0.0, 0.3, 0.5 e 1.0 µg/mg de alimento) durante 10 dias. Os suínos foram abatidos em escalonadamente aos 1, 5, 7 e 10 dias pós-desmame e foram tomadas amostras do intestino delgado para determinar alguns parâmetros morfológicos através da análise computacional de imagens. O delineamento estatístico utilizado foi em blocos casualizados em um arranjo fatorial 4x4. Resultados: o resultado foi que LPS diminuiu a altura e a área das vilosidades e aumenta sua largura e profundidade e amplitude das glândulas intestinais. Estes efeitos podem diminuir a absorção intestinal de nutrientes, aumento de co-infecção com outros patógenos ea apresentação do pós-desmame síndrome diarréica. Conclusões: este estudo mostra a utilidade da análise morfométrica computadorizada para avaliar o efeito do LPS sobre parâmetros morfológicos intestinais, de modo que poderiam ser utilizados em futuros estudos para pesquisar a fisiopatologia da enterite agentes causadores e avaliar estratégias terapêuticas.
ABSTRACT
BACKGROUND: An acute lung injury(ALI) is characterized by the recruitment, activation, and apoptosis of inflammatory cells, numerous products released by inflammatory cells such as reactive oxygen species, inflammatory mediators, and a variety of proteolytic enzymes. It was reported that bacterial infections in diabetics showed impaired PMN functions such as reduced PMN respiratory burst and decreased microbicidal activity in inflamed tissue. However, the effect of the proteinase - inhibitor (MMP-9 vs TIMP-1) in ALI in diabetics is unclear. This study evaluated the differences in the expression of MMP-9 and TIMP-1 after the stimulation of endotoxin in a rat model. METHODS: Six-week-old male Sprague-Dawley rats were classified into normal, DM, LPS and DM+LPS groups. The peripheral blood, BAL fluids, and lung tissues were obtained from individual rats. The MMP-9 activity was measured by gelatin zymography and the TIMP-1 level was measured by Western blotting. RESULTS: The total BAL cells of the DM-LPS groups were significantly lower than the LPS groups (p < 0.01). The MMP-9 activities in the serum were higher in the DM+LPS groups than in the other groups. The MMP-9 activities in the BAL fluids were significantly higher in the DM+LPS group than in the normal and diabetic rats (p < 0.05). TIMP-1 expressions in the BAL fluids were significantly lower in the DM+LPS group than other groups (p < 0.05). The ratio between MMP-9 and TIMP-1 in the BAL fluids was significantly higher in the DM+LPS groups (p < 0.05). CONCLUSION: In ALI in diabetics the higher MMP-9 activity and lower TIMP-1 level are believed to prolonged and intensify the course of inflammation.
Subject(s)
Animals , Humans , Male , Rats , Apoptosis , Bacterial Infections , Blotting, Western , Gelatin , Inflammation , Lung , Matrix Metalloproteinase 9 , Models, Animal , Peptide Hydrolases , Rats, Sprague-Dawley , Reactive Oxygen Species , Respiratory Burst , Tissue Inhibitor of Metalloproteinase-1ABSTRACT
BACKGROUND: Bacterial infections in diabetic patients are an important cause of increased morbidity and mortality. It has been reported that bacterial infections in diabetics showed more impaired PMN functions such as reduced PMN respiratory burst and decreased microbicidal activity in inflammed tissues. Also, apoptosis(programmed cell death) is postulated to be a key mechanism for neutrophil elimination. It is very important that PMN apoptosis keeps the balance from an area of inflammation. Actuallly, as little was known about PMN apoptosis and respiratory burst in diabetes, we investigated PMN apoptosis and hydrogen peroxide production after endotoxin exposure. METHODS: Peripheral venous blood samples were collected by routine venipuncture from healthy volunteers and diabetics to harvest neutrophils. We respectively measured the PMN apoptosis, the production of hydrogen peroxide, and the cell viability. RESULTS: Normal neutrophils showed a tendency to decreased apoptosis after endotoxin treatment. In patients with diabetes, PMN apoptosis was significantly decreased compared with healthy controls. In addition, the LPS-induced neutrophils in diabetics demonstrated more decreased apoptosis. However, the production of hydrogen peroxide was not different between groups. CONCLUSION: These observations suggest that the decreased PMN apoptosis in diabetics with endotoxin exposure may also affect the increased susceptibility and severity of infections.