Efecto del lipopolisacarido (LPS) de E. coli sobre la secreción de mucinas intestinales en lechones post destete

Abstract

RESUMEN: Actualmente se desconoce el efecto del LPS de Escherichia coli sobre la cantidad de células caliciformes, sobre la secreción de mucinas en diferentes regiones del intestino en cerdos durante el período posdestete y si el patrón de distribución de las mucinas está relacionado con el desarrollo de enteritis. Objetivo: Determinar el efecto del LPS de E.coli sobre la secreción de mucinas en el intestino de lechones recién destetados. Métodos: Se realizó un estudio experimental con 52 lechones destetados precozmente (21 días), que fueron alimentados con una dieta basal adicionada con cuatro niveles de LPS (0.0, 0.3, 0.5 y 1.0 ug/mg) durante 10 días. Los cerdos se sacrificaron los días 1, 5, 7 y 10 posdestete para tomar muestras de intestino delgado y colon, realizar coloraciones histoquímicas (Azul alcián pH 1.0, 2.5 y ácido periódico schiff), calcular la cantidad de células caliciformes y el tipo de mucinas ácidas sulfatadas, no sulfatadas o neutras por ellas producidas. Resultados: Con respecto al número de células caliciformes que expresaron mucinas ácidas en los diferentes tiempos del periodo posdestete, se observó que tanto aquellos animales que recibieron la dieta basal como los sometidos a las dietas experimentales presentaron una disminución de la secreción de mucinas ácidas el quinto día, con posterior recuperación de los parámetros los días 7 y 10, las mucinas neutras en cambio, incrementaron el día 5 con una posterior disminución los días 7 y 10 posdestete; Al comparar las dietas experimentales, se observó una disminución del número de células caliciformes secretando los diferentes tipos de mucinas a dosis mayores de LPS, principalmente con la Dieta dos (D2: 0.5 ug/mg de LPS). Conclusiones: El destete a los 21 días y la adición LPS de E.coli a la dieta, generan cambios en la secreción de mucinas, afectan la integridad del epitelio y el balance entre la secreción de mucinas ácidas y neutras por las células caliciformes.

ABSTRACT: In swine, early weaning generates morphological and physiological changes in the intestine that predispose to the development of enteritis and have been associated with gram negative bacteria such as Escherichia coli, which have LPS, a potent pathogenic factor. In the intestine, the goblets cells produce mucin, which forms a protective gel, mediates the bacteriahost and bacteria-bacteria interaction. Is currently unknown E.coli LPS effect on the number of goblets cells and the types of mucins secreted in different portions of the intestine of pigs and whether these changes are related to the development of post-weaning enteritis in this period. This knowledge is necessary to develop alternative methods for handling enteritis in postdeste period. Objective: determine the effect of E. coli LPS on the number of goblet cells and the type of mucins produced in the small and large intestines of recently weaned piglets. Methods: We conducted an experimental study with 52 piglets weaned at 21 days, were fed a basal diet supplemented with four levels of LPS (0.0, 0.3, 0.5 and 1.0 mg / mg of food) for 10 days. Pigs were sacrificed on days 1, 5, 7 and 10 post-weaning and samples of small and large intestine were taken; histochemical stainings were made (PAS and Alcian blue at pH 1.0 and pH 2.5) to determine the number of goblet cells and amount of neutral and acidic mucins sulfated and nonsulfated by computerized image analysis. We conducted a 4x4 factorial multivariate statistical analysis (GML) with a Duncan test to compare treatments. Results: With regard to the number of goblet cells expressing different acidic mucin evaluated times postweaning period, it was observed that those animals that received both the basal diet as those subjected to the experimental diets had a decrease of the acid mucin secretion the fifth day, with subsequent recovery of the parameters for the 7 and 10 postdeste, whereas neutral mucins, increased on day 5 with a subsequent decrease for 7 to 10 postdeste; By comparing the experimental diets, there was a decrease of number of goblet cells to secrete mucins different types of LPS at higher doses, mainly with D2 (0.50 ug / mg of LPS). Conclusions: We found an effect of weaning time and dose of LPS on the secreted mucin, acidic mucins being the most affected. The effect of weaning on the type expressed mucin was enhanced by LPS, noting more deleterious effect on goblet cells with higher doses. These changes may compromise the protective function of mucins and affect the integrity of the epithelium with changes in the number of goblet cells, which explains some of alterations that can lead to the development of post-weaning diarrhea syndrome.