Proliferating cells differentiate into neurons in the hippocampal CA1 region of gerbils after global cerebral ischemia.

Neurogenesis in the hippocampal dentate area of adult animals is stimulated by neuropathological diseases. We investigated here whether transient global cerebral ischemia in adult gerbils, which causes neurodegeneration selectively in CA1 pyramidal neurons, affects endogenous stem cells in the dentate area as well as CA1 region. The two key findings of this study are that: (1), global ischemia markedly increases neurogenesis in hippocampal subgranular zone from immature neuronal progenitor cells (betaIII-tubulin) to mature neurons (NeuN); and that (2), there is also an appearance of newly born neurons in the degenerated CA1 pyramidal cell layer, as demonstrated by immunofluorescence. These results provide evidence for an increased neurogenesis in the gerbil CA1 pyramidal cell layer four weeks following global cerebral ischemia, which could promote morphological and functional recovery after cerebral ischemia.