Fig. 3

Riluzole treatment reverses cranial radiation-induced synaptic loss. Adult male mice were exposed to cranial RT and 48 h later received riluzole (RZ, 13 mg/kg) in drinking water for 6–7 weeks. Synaptic protein marker, synaptophysin, in the molecular layer (ml) of hippocampal dentate gyrus (dg, A, B) and CA1 stratum radiatum (sr, C, D) emanating from the pyramidal neuron layer (pyr) was quantified using immunofluorescence staining, confocal microscopy and 3D algorithm-based unbiased fluorescent puncta analysis of synaptophysin immunoreactivity (magenta; DAPI nuclear stain, blue). Cranial RT (RT + Vehicle) significantly reduced the synaptophysin immunoreactivity in the dg ml, and CA1 sr regions compared with Control + Vehicle group. Irradiated mice receiving RZ showed a significantly increased synaptophysin immunoreactivity compared with the RT + Vehicle group. Data ise presented as mean ± SEM (N = 8 mice per group). P values were derived from two-way ANOVA and Bonferroni's multiple comparisons test. Scale bars, 30 μm, (B, D)