IMMUNOCYTOCHEMICALLY DETECTABLE METALLOTHIONEIN IS EXPRESSED BY ASTROCYTES IN THE ISCHEMIC HUMAN BRAIN

The metallothioneins in vitro are both effective free radical and tran sitional metal ion scavengers, For this reason we investigated the exp ression of this protein in the normal CNS and after ischaemia using a monoclonal anti-metallothionein antibody to metallothionein isoforms I and II. Using immunohistochemistry and confocal laser scanning micros copy, we found anti-GFAP and anti-metallothionein were co-localized in astrocytes at the edges of infarcts. Energy dispersive X-ray microana lysis demonstrated high levels of copper and iron in the metallothione in positive reactive astrocytes. On the basis of the in vitro properti es of these proteins, the functional importance of metallothionein in reactive astrocytes could be as a free radical scavenger and metal ion chelator.