Hippocampal-dependent neurocognitive impairment following cranial irradiation observed in pre-clinical models: current knowledge and possible future directions

Br J Radiol. 2016;89(1057):20150762. doi: 10.1259/bjr.20150762. Epub 2015 Oct 30.

Abstract

We reviewed the literature for studies pertaining to impaired adult neurogenesis leading to neurocognitive impairment following cranial irradiation in rodent models. This compendium was compared with respect to radiation dose, converted to equivalent dose in 2 Gy fractions (EQD2) to allow for direct comparison between studies. The effects of differences between animal species and the dependence on animal age as well as for time after irradiation were also considered. One of the major sites of de novo adult neurogenesis is the hippocampus, and as such, this review also focuses on assessing evidence related to the expression and potential effects of inflammatory cytokines on neural stem cells in the subgranular zone of the dentate gyrus and whether this correlates with neurocognitive impairment. This review also discusses potential strategies to mitigate the detrimental effects on neurogenesis and neurocognition resulting from cranial irradiation, and how the rationale for these strategies compares with the current outcome of pre-clinical studies.

Publication types

  • Review

MeSH terms

  • Age Factors
  • Animals
  • Behavior, Animal / radiation effects*
  • Cognition Disorders / etiology*
  • Cranial Irradiation / adverse effects*
  • Hippocampus / radiation effects*
  • Neurogenesis / radiation effects
  • Radiation Dosage
  • Radiation Injuries, Experimental / complications*
  • Rats