Influence of Stress Preconditioning on Hippocampal Neuronal Cell Death and Neurogenesis in Rat Cerebral Ischemia

Stress-associated exacerbation of neuronal cell death following cerebral ischemia has been reported. Here, we evaluated the effect of stress prior to cerebral ischemia on neuronal cell death in rats. Male Sprague–Dawley rats were subjected to global ischemia. Four experimental groups were used (1) control, (2) ischemia, (3) stress, (4) ischemia following stress. A forced swimming test was used to impose stress. At 7 days after ischemia, we evaluated hippocampal neuronal cell death with Fluoro-Jade B staining and neurogenesis with BrdU staining. Hippocampal neuronal cell death in the ischemia group was significantly increased compared with that in the control group. The stress group also showed a significant increase of cell death compared with the control. The ischemia following stress group showed a much greater increase of hippocampal neuronal cell death than the other groups. As for neurogenesis, BrdU-positive cells in the ischemia group were significantly increased compared with the control and stress groups. In the ischemia following stress group, BrdU-positive cells were significantly decreased compared with the ischemia group. Thus, imposition of stress prior to cerebral ischemia appears to exacerbate neuronal cell death and to inhibit neurogenesis in rat hippocampus.