PHOTOCHEMICAL BRAIN INJURY IN RATS TRIGGERS DNA FRAGMENTATION, P53 AND HSP72

THE aim of the study was to examine whether apoptosis, apoptosis-relat ed protein p53 and heat-shock protein (HSP) 72 participate in the resp onse of the brain to focal injury. Male Sprague-Dawley rats received i ntravenously a photosensitive dye rose bengal, Unilateral cortical thr ombosis was induced by illuminating the skull of rose bengal-treated r ats for 10 min with a focused beam of light. Animals were killed and b rains were processed for immunohistochemical detection of DNA fragment ation, p53, and HSP72 kD. DNA fragmentation and p53 were increased onl y in the perifocal area in the cortex ipsilateral to the thrombotic fo cus, while HSP72 increased throughout the ipsilateral cortex, except i n the immediate perifocal area. The results suggest that in response t o focal brain some cells die through an apoptotic process that involve an accumulation of p53.