Glatiramer acetate reverses cognitive deficits from cranial-irradiated rat by inducing hippocampal neurogenesis

• GA improved the cognitive ability of cranial-irradiated rats.
• GA increased neurogenesis in hippocampus of cranial-irradiated rats.
• GA reverted the Th1/Th2 balance (increased IFN-γ and decreased IL-6, IL-4).
• GA increased Iba-I-positive microglia in hippocampus of cranial-irradiated rats.
• GA increased BDNF and IGF-1 levels in hippocampus of cranial-irradiated rats.

Patients received cranial-irradiation can be affected with cognitive deficits and decreasing hippocampal neurogenesis. In this work, we characterized the cognitive ability and immune-induced neurogenesis of the pre- and post-treated cranial-irradiated rats with Glatiramer acetate (GA), known as a weak CNS auto-antigen. The GA-treated rats displayed better cognitive abilities in Morris water maze (MWM). The numbers of Iba-I-positive microglia, BrdU+/DCX+ cells and BrdU+/NeuN+ cells in hippocampus increased, which are accompanied with increased IFN-γ and decreased IL-6, IL-4. Furthermore, GA reverted the Th1/Th2 balance. GA treatment can reverse the cognitive deficits caused by cranial irradiation through a mechanism that likely involves immunomodulation.