Infarct model, experimental design and quantification of the number of bromodeoxyuridine (BrdU)-positive cells in the subgranular zone. (A) Location and morphology of a photothrombotic infarct in the sensorimotor cortex on the brain surface (dotted line) and on a coronal BrdU-stained section at day 4 postsurgery. Scale bars represent 5 mm. (B) Schematic illustration of the experimental design. Prior to surgery all animals received intraperitoneal injections of the proliferation marker BrdU twice daily for 4 consecutive days and survived till day 4, 7, 14 or 28. (C) Immunohistochemically stained sections with antibodies against BrdU through the dentate gyrus of the hippocampus (two magnifications). (D) Diagram of the total number of BrdU-positive cells in the subgranular zone of the dentate gyrus at day 4, 7, 14 and 28. BrdU-positive cells significantly increase at day 14 and 28 postsurgery. Error bars represent S.E.M.. Significant differences (P < 0.05) are indicated by an asterisk.