Precursor cells have been shown to be affected by oxidative stress, in vivo and 
vitro, but little is known about the expression of antioxidant mechanisms in 
neuronal/glial differentiation. We have characterized the expression of Cu/Zn 
superoxide dismutase (Cu/Zn SOD), one of the main antioxidant proteins involved 
in the breakdown of superoxide, in the immature rat dorsolateral subventricular 
zone (SVZ), rostral migratory stream (RMS) and hippocampal subgranular zone 
(SGZ). Progenitor cells were identified immunohistochemically on cryostat 
sections by 5'Bromodeoxyuridine (BrdU) incorporation and expressing cells were 
further characterized using double labeling for progenitor markers. In the SVZ, 
only a subpopulation of BrdU+ cells, mostly found in the medial SVZ, expressed 
Cu/Zn SOD. These cells were mostly nestin+ and some were also vimentin+. In 
contrast, in the lateral SVZ few Cu/Zn SOD+/BrdU+ cells were found. These were 
primarily nestin+, vimentin-, showed some PSA-NCAM expression, but only a few 
were NG2+. In the RMS and SGZ virtually all BrdU+ progenitors were Cu/Zn SOD+ 
and expressed nestin and vimentin. Some RMS cells were also PSA-NCAM+. These 
findings show a heterogeneous expression of Cu/Zn SOD in restricted cell types 
in the germinative zones and suggest a role for antioxidant Cu/Zn SOD in 
progenitor cells of the immature rat brain.