Increased expression of transferrin receptors and iron in amoeboid microglial cells in postnatal rats following an exposure to hypoxia

This study was aimed to ascertain the effects of hypoxia on regulation of i ron in the brain of newborn rats. At 3 h and 1 day after hypoxic exposure t ransferrin receptor expression as detected immunohistochemically with the a ntibody OX-26, and the iron content as shown by Perls' staining of amoeboid microglial cells was markedly increased. The induced changes, however, wer e not evident at 10 min and in longer surviving rats killed at 3 and 7 days . It is suggested that the upregulation of transferrin receptor expression coupled with iron uptake by amoeboid microglial cells in the periventricula r regions is a protective mechanism to facilitate the sequestration of exce ss iron that may have been released either from the iron-rich oligodendrocy tes, or accumulated due to a disruption of its normal transportation follow ing the hypoxic insult. This would help protect the brain from harmful effe cts of iron. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.