Increased astrocytic expression of metallothioneins I + II in brainstem of adult rats treated with 6-aminonicotinamide

The cerebral distribution of metallothioneins I and II (MT-I + II) was studied in adult rats subjected to i.p injection with the gliotoxin 6- aminonicotinamide (6-AN). Grey matter regions of the brainstem heralded numerous OX-42-positive macrophages and microglia, indicating that 6-AN primarily caused damage to this part of the brain. In the grey matter regions infiltrated with OX-42-positive cells, astrocytes identified by anti-GFAP and MT-I + II antibodies were almost absent. By contrast, in the peripheral zone of the lesioned regions numerous reactive GFAP- and MT-I + II-positive astrocytes were observed. The blood-brain barrier (BBB) to serum albumin was compromised in the entire brainstem. The astrocytic expression of MT-I + II could reflect the brains needs to scavenge metal ions released from either damaged cells or plasma proteins entering the brain due to the injured BBB, as well as it could reflect the potential antioxidant function of MT-I + II.