Fig. 5

Riluzole treatment did not prevent cranial radiation-induced decline in neurogenesis. WT adult male mice received cranial RT (9 Gy) and treated with riluzole (RZ, 13 mg/kg) 48 h later in  their drinking water for 6–7 weeks. Two weeks post-RT, mice were treated with BrdU and hippocampal neurogenesis was quantified using newly born neuron marker, doublecortin (DCX), and BrdU-NeuN dual-immunofluorescence staining in the hippocampal dentate gyrus (DG) sub-granular zone (SGZ) and molecular layer (ML) 6-7 weeks after the BrdU treatment. Cranial RT (RT + Vehicle) significantly reduced the number of DCX⁺ neurons (red, A–D) in the hippocampus compared with either Control + Vehicle or Control + RZ groups E. RT also significantly reduced neurogenesis, as indicated by the reduced percentage of BrdU⁺ cells (red) differentiating into the mature neurons (green, NeuN; F–I) in the RT + Vehicle group compared with either Control + Vehicle or Control + RZ groups (J). Riluzole treatment to the irradiated animals did not prevent the loss of DCX⁺ newly born neurons and the decline in dentate neurogenesis (BrdU⁺-NeuN⁺ dual-fluorescent cells). Data is presented as mean ± SEM (N = 6–16 mice per group). P values were derived from two-way ANOVA and Bonferroni's multiple comparisons test. Scale bars, 50 μm, (A–D) and (F–I)