Pre- and postweaning iron deficiency alters myelination in Sprague-Dawley rats

Abstract

Iron deficiency in early life is associated with hypomyelination; however, the role which iron plays in myelinogenesis is not clearly established. In this study, we examined the effect of preweaning [postnatal days (PND) 4-14 and PND 4-21] and postweaning (PND 21-63) iron deficiency on hindbrain 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) activity (marker of oligodendrocyte metabolic activity) and myelin basic protein (MBP) concentrations. Both CNPase activity and concentrations in the cerebrum and hindbrain were significantly lower in pre- and postweaning iron-deficient rats. Similarly, MBP concentrations were also reduced (25-35%) in all three groups of iron-deficient animals. Iron-deficient animals also had significant alterations in the fatty acid composition of individual phospholipids within the hindbrain as well as changes in cytochrome oxidase activities. These studies show that postnatal iron deficiency, for as little as 10 days, can significantly alter the production of myelin and oligodendrocyte functioning. Importantly, postweaning iron deficiency was still associated with a decrease in CNPase activity and MBP concentrations despite occurring well past a likely key sensitive period of peak myelinogenesis at PND 8-12. This suggests that iron deficiency in later life, as well as during early postnatal growth, can effect the production and maintenance of myelin.