Irradiation attenuates neurogenesis and exacerbates ischemia‐induced deficits

Abstract

Increased neurogenesis after cerebral ischemia suggests that functional recovery after stroke may be attributed, in part, to neural regeneration. In this study, we investigated the role of neurogenesis in the behavioral performance of gerbils after cerebral global ischemia. We used ionizing radiation to decrease neural regeneration, and 2 weeks later cerebral global ischemia was induced by bilateral common carotid artery occlusion. One month after the occlusion, the animals were behaviorally tested. Irradiation alone reduced neurogenesis but did not change vascular or dendritic morphology at the time of behavioral testing. Neither did irradiation, ischemia, or combined treatment impair rotor-rod performance or alter open-field activity. Gerbils subjected to both irradiation and ischemia demonstrated impaired performance in the water-maze task, compared with those that received only ischemia, radiation, or no treatment. These impairments after cerebral global ischemia under conditions of reduced neurogenesis support a role for the production of new cells in mediating functional recovery.

Reappearance of Hippocampal CA1 Neurons after Ischemia is Associated with Recovery of Learning and Memory

“…This will not be an easy task, since the region of origin of the new CA1 neurons is not unequivocally shown. A nonselective inhibition of neurogenesis by mitotic inhibitors or irradiation will not be sufficient to solve the issue, since such treatment is known to impair learning and memory also in nonischemic animals, possibly through inhibition of neurogenesis in the subgranular zone (Feng et al, 2001;Raber et al, 2004;Shors et al, 2001).…”

Mesenchymal stem cells as a treatment for neonatal ischemic brain damage

“…In the healthy adult brain, neurogenesis is necessary to maintain neurological function. Ablation of NPCs from the dentate gyrus reduces neurogenesis and impairs functional plasticity, showing the importance and necessity of neurogenesis after brain injury (57,58).…”

Adult Neurogenesis and the Ischemic Forebrain

“…Deficits in ischemia-induced neurogenesis may contribute to impaired behavioral recovery. Raber et al (2004) used irradiation to suppress neurogenesis in young adult gerbils and found that, in comparison with animals subjected to cerebral ischemia alone, irradiated animals that experienced ischemic injury display impaired performance on various behavioral tasks. Although confounding variables associated with irradiation complicate interpretation of these data, ongoing neurogenesis might be important for functional recovery from brain insults, and the age-dependent reduction in neurogenesis may impede recovery from injury.…”