Lipid peroxidation in the postnatal rat brain - Formation of 4-hydroxynonenal in the supraventricular corpus callosum of postnatal rats

Lipid peroxidation is known to be associated with many neurodegenerative di seases and with traumatic brain injury, but its occurrence in the normal de veloping brain has not been reported. The present study was carried out usi ng a specific antibody that recognises proteins modified by the end-product of lipid peroxide decomposition, 4-hydroxynonenal (HNE), to evaluate evalu ate possible lipid peroxidation products in the brains of developing rats b y immunocytochemistry and electron microscopy. Moderately dense labelling w as observed in the supraventricular corpus callosum in the 7- and 8-day-old rats, whilst very dense labelling was observed in the same region, in the 9- and I0-day-old rats. Very little immunoreactivity was observed at 14 day s, and no staining was observed in the corpus callosum in adult rats. HNE s taining was not observed in neuronal cell bodies that give rise to callosal axons in the overlying cerebral cortex. Electron microscopy showed dense H NE staining on the basal laminae of blood vessels and on the plasma membran es of unmyelinated axons. Large numbers of rounded cells with features of o ligodendrocyte precursor cells were labelled by Perl's stain in the suprave ntricular corpus callosum at postnatal day 7 and postnatal day 10, i.e. at times cor responding to high levels of HNE immunoreactivity. In contrast, v ery few such cells were observed in the adult brain, corresponding to the v ery little or no Perl's staining in the adult. These results suggest that l ipid peroxidation observed in the supraventricular corpus callosum at postn atal day 10 could result from an accumulation of iron in this region, at th is time.