Changes in apoptosis-related protein (p53, Bax, Bcl-2 and Fos) expression with DNA fragmentation in the central nervous system in rats after closed head injury

This study aimed to examine the temporal profile of neuronal apoptosis in t he central nervous system (CNS) following closed head injury in rat. Fos im munoreactivity was detected in neuronal nuclei in the cerebral cortex at 2 h after head injury. At 4 h, Bax protein expression was elevated with a con comitant down-regulation of Bcl-2 expression. Along with this, a marked imm unoexpression of p53 was also observed in these cells. Double immunolabelli ng study has shown the colocalization of Bax immunoreactivity with Bcl-2 an d p53. In rats killed 1 day after injury, a variable number of transferase d-UTP nick-end labelling positive cells were observed. Present findings sug gest that the upregulation of p53 and a shift in the ratio of Bcl-2 to Bax may contribute to neuronal apoptosis in the CNS after closed head injury. ( C) 2000 Elsevier Science Ireland Ltd. All rights reserved.