REGULATION OF APOPTOSIS-ASSOCIATED PROTEINS IN CELL-DEATH FOLLOWING TRANSIENT FOCAL ISCHEMIA IN RAT PUPS

Apoptosis is a process whereby developmental or environmental stimuli activate a genetic programme to execute a specific series of events th at culminate in the death and efficient disposal of a cell. Although a series of recent data suggested that neuronal death following cerebra l ischemia occurs through an apoptotic pathway, additional work is nee ded to establish the existence of a causal relationship between gene e xpression and DNA breaks in neuronal death. We investigate the role of p53 and Bar proteins in the induction of apoptosis induced by a new t ransient focal ischemia model in the rat pup. Our results show that wi ld-type p53 exerts a significant and time-dependent effect in the init iation of apoptosis, and that apoptosis is induced via DNA-strand brea kage. Subsequently, increased Bar expression was observed in the cytop lasm of dying cells located in the infarct, whereas an increased Bcl-2 and hsp72 staining was detectable in survival cells and reactive glia present at the periphery of the lesion.