Cell death and immunohistochemistry of p53, c-Fos and c-Jun after spermineinfection into the rat striatum

Administration of polyamines into the central nervous system results in tis sue damage, possibly through the excitotoxic actions of the NMDA receptor. Direct injection of 100 nmol of spermine into the rat striatum produced a l esion equivalent to approximately 50% of the striatum. Analysis of the DNA in this region revealed the distinct ladder-like pattern of degradation oft en associated with apoptosis. This DNA fragmentation was confirmed in vivo using terminal deoxynucleotidyl-transferase-mediated biotinylated deoxyurid ine triphosphate nick end labelling (TUNEL). The morphology of the TUNEL-po sitive cells showed marked differences at the needle tract when compared wi th cells in damaged areas away from the needle tract, suggesting a differen tial mechanism of cell death in these two regions. The patterns of p53, c-F os and c-Jun protein expression were determined using immunohistochemistry. The number of p53-immunoreactive cells increased up to 14 h and returned t o basal levels by 24 h. c-Fos protein expression transiently increased, pea king at 8 h after injection, c-Jun exhibited a protracted pattern of expres sion, remaining elevated up to 24 h. p53 protein expression was colocalised with TUNEL staining in areas away from the needle tract, but not in cells at the needle tract, suggesting once again a differential mechanism of cell death. At 14 h, c-Fos and c-Jun were not colocalised with TUNEL staining, suggesting that they are either not involved with the cell death process or that the time course of protein expression and the onset of DNA fragmentat ion do not overlap. This work represents the first characterisation of proc esses associated with cell death induced by spermine in vivo.