Abstract: Objective To investigate the effects of iron on the expression and regulation of divalent metal transporter 1 (DMT1) that may play an important role in the physiological brain iron metabolism. Methods Both the contents of ferric and ferrous iron as well as DMT1 (+IRE) and DMT1 (-IRE) protein expression were evaluated with iron histochemistry and immunohistochemistry in cerebral cortex (CC) after intracerebroventricular injection (ICV) of 500μg iron dextran/day for 3 or 7 days (each group contained 6 rats). Results Iron histochemistry results showed that both the ferric and ferrous iron levels in CC were altered obviously after ICV for 7 days. Immunohistochemistry results indicated that the expression of DMT1 (+IRE) in CC was not altered significantly after 3 days of ICV. Whereas the expression of DMT1 (+IRE) was increased significantly after 7 days of ICV when ferrous iron was increased significantly. Contrary to that of DMT1 (+IRE) expression in the same region, there were no significant alterations in DMT1 (-IRE) expression in CC in spite of the existence of the altered brain iron levels, compared with that of control groups. Conclusion These data demonstrate that DMT1 (+IRE) expression is correlated primarily with brain iron levels; especially, its regulation is correlated positively with iron (ferrous iron) in adult rat CC, compared with those of saline-injected control rats.The effect of iron on the different isoforms of DMT1 expression may be different in different brain regions, but further investigations are needed to clarify these issues.

Key words: Cerebral cortex, Iron, Divalent metal transporter 1, Immunohistochemistry, Rat