Influence d'un retard de croissance sur la perméabilité de la barrière hémato-encéphalique chez le rat nouveau-né exposé au plomb

Postnatal administration of lead to young rats via maternal milk increases the permeability of the blood–brain barrier to trypan blue. However, since this regimen delays postnatal maturation, the question arises whether growth retardation per se could explain the altered permeability to the dye. The present investigation was undertaken to examine this possibility. A first group of newborn rats were fed by dams having free access to normal food; a second group was fed by dams receiving 3% lead as the acetate salt in their food; a third group was fed by dams whose normal diet was restricted to the amount taken daily by dams of the second group. Signs of encephalopathy as shown by urinary incompetence and hind-limb paralysis were observed only in young pups exposed to lead; similarly, only the latter showed increased brain permeability to trypan blue. These results suggest that the altered permeability of the blood–brain barrier in young rats is the direct consequence of lead toxicity and not of growth retardation secondary to a nutritional effect of lead.