Aluminum uptake and effects on transferrin mediated iron uptake in primarycultures of rat neurons, astrocytes and oligodendrocytes

Transferrin (Tf) is known primarily for its role in the transport and cellu lar uptake of iron (Fe). Tf is also the major serum binding protein for Al. In this study, primary rat oligodendrocyte, neuron and astrocyte cultures were found to differ in Tf mediated Fe and Al uptake and in the effect of A I-Tf on Fe-Tf uptake during 4 h incubation periods. When incubated with AI- Tf(1.25 mu M), oligodendrocytes displayed a 3- to 4-fold increase (p=.0002) in Al, neurons demonstrated a much smaller (p=.06) increase, and no increa se was seen for astrocytes. When incubated with equimolar Al citrate or Al chloride, no increase in cellular Al was seen in any of the three cell type s. Oligodendrocytes, astrocytes and neurons all demonstrated greater Fe-59 uptake from Fe-TI than Fe chloride. This uptake could be inhibited by exces s Fe-Tf in oligodendrocytes and neurons, but not astrocytes. A small but si gnificant inhibition of Fe-59 uptake from Fe-Tf was seen after addition of Al-Tf to the incubation medium of oligodendrocytes, but not neurons or astr ocytes. Oligodendrocytes may be particularly vulnerable to the accumulation of excess intracellular Al, and to interference of Al with Fe uptake. Such effects could contribute to Al-induced neurotoxicity if they result in alt ered myelin formation or maintenance. (C) 1999 Intox Press, Inc.