CONICET | Buscador de Institutos y Recursos Humanos

Resumen: Food and the metabolites generated during digestion and gastrointestinal transit play a major role in the consumer`s health. Many antinutritional and/or potentially toxic compounds are daily consumed by humans and animals. Among them, plant lectins are specific carbohydrate-binding proteins that are widespread in the diet, being present in many food items such as vegetables, fruits, cereals, beans and seeds. They are highly resistant to inactivation by cooking and by digestive processes and therefore it is likely that the colonic epithelium is exposed to many lectins that have retained their biological activity. In the intestinal lumen, lectins could act as antiproliferative agents or as tumour promoters by stimulating cell proliferation. They can cause deleterious morphological and physiological changes in the intestinal mucosa such as inhibition of digestive enzymes and shortening of microvilli that conduce to a reduction of the absorptive function. In previous studies we have determined that dairy propionibacteria have the ability to remove dietary lectins preventing their cytotoxic effects on intestinal epithelial cells. In the present study we assessed the probiotic potential of dairy propionibacteria to protect the intestinal mucosa from the deleterous effects caused by toxic lectins commonly present in food. Six week old Balb/c mice received during 4 weeks a daily dose of 200 mg of concanavalin A by gavage with or without the simoultaneous administration of 5 x 108 UFC of Propionibacterium acidipropionici CRL 1198. The animals were sacrificed 24 hours after the treatments were finished in order to determine: organs weight, structural alterations by macroscopic and microscopic examination of the intestinal mucosa, glycolitic activities of microflora and brush border membranes, mucin content and sugars compositon, counts of main microflora components, SCFA production and genotoxicity on colonic cells. Con A feeding produced a significant increase of stomach size and affected feed efficiency since some disaccharidases activities were decreased. Structural alterations such as shortening of crypts and villi, a decrease in the mucous layer thickness and dysplastic colonic crypts were produced. No significant changes were observed in the main components of the intestinal microflora and SCFA production, although lectin was not fermented and inhibited to some extent the colonic fermentative activity. ConA feeding also induced a greater susceptibility of colonic cells to genotoxic damages produced by DMH (in vivo) or H2O2 (in vitro). P. acidipropionici prevented to different extents the damages caused by con A in the arquitecture and physiology of the intestinal mucosa. Results suggest that consumption of foods containing these propionibacteria would be a tool to avoid lectins-mucosa interactions and its undesirable effects both in humans and animals.