Sustained calpain activation associated with lysosomal rupture executes necrosis of the postischemic CA1 neurons in primates

ABSTRACT: Because of the paucity of primate experimental models, the precise molecular mechanism of ischemic neuronal death remains unknown in humans. This study focused on nonhuman primates to deter-mine which cascade necrosis or apoptosis is predominantly involved in the development of delayed (day 5) neuronal death in the hippocampal CA1 sector undergoing 20 min ischemia. We investigated expression, activation, and/or translocation of -calpain, lysosome-associated mem-brane protein-1 (LAMP-1), caspase-3, and caspase-activated DNase (CAD), as well as morphology of the postischemic CA1 neurons and DNA electrophoresis pattern. Immunoblotting showed sustained (immediately after ischemia until day 5) and maximal (day 3) activation of -calpain. The immunoreactivity of activated -calpain became remarkable as coarse granules at lysosomes on day 2, while it translocated throughout the perikarya on day 3. The immunoreactivity of LAMP-1 also showed a dynamic and concomitant translocation that was maximal on days 2–3