Toxicity of aluminum exposure to the neonatal and immature rabbit

To assess aluminum toxicity to the neonatal and immature rabbit, rabbits received 20 sc Al lactate injections of 0 or 400 mumol Al/kg during the first month postpartum or 0, 25, 100, or 400 mumol Al/kg during the second month postpartum. Results were compared to studies in which pregnant, lactating, or adult rabbits received comparable Al injections. Aluminum injections to neonatal rabbits decreased milk consumption, but not as severely as seen in neonatal rabbits of does receiving Al during gestation or lactation. Reduction in body weight gain was greater in adult rabbits than in any group of rabbits exposed to Al at a younger age. Increased carpal joint width, suggestive of poor bone calcification, was observed in rabbits receiving 400 mumol Al injections during the second postnatal month, but not in any other Al-exposed group. Tissue Al accumulation, particularly in reticuloendothelial organs, the kidney and skeletal system, seems to be most pronounced in adult rabbits. Clearance of Al from these tissues is extremely slow. Learning and memory changes were not observed after Al treatment of neonatal and immature rabbits, compared to the biphasic effect (enhancement after low doses, attenuation after high doses) seen in gestationally exposed rabbits and the attenuation observed in adult rabbits. Taken together, these results demonstrate prolonged effects of reduced body weight, impairment of bone formation, and tissue Al accumulation following Al exposure that are not readily reversed with termination of exposure. The results show that the immature rabbit is most susceptible to Al-induced skeletal toxicity and the mature rabbit most susceptible to Al-induced behavioral toxicity.