Single acute treatment with FTY720 does not protect from kainic acid (KA)-induced neurodegeneration in vivo. (A) Schematic timeline of experimental protocol. FTY720 was applied as a single icv dose together with KA. Seizure score was evaluated at the end of the surgery observing the animals during 30 min intervals over a period of 2 h. Animals were sacrificed 3 days after icv injection and brain tissues processed for immunohistochemical analysis. (B) Effect of FTY720 (1 μg/2 μl, icv) on seizure-like behaviour induced by KA icv injection (0.5 μg/2 μl). Seizure was scored as described in the ‘Methods’ section, with the higher score indicating greater seizure severity. The mean seizure score for KA group (n = 6) and KA + FTY720 group (n = 6) was plotted against time after icv. (C, D) Quantification of the extent of the lesion in animal icv injected with KA (n = 6) and KA + FTY720 (n = 6) after Nissl’s staining. Eight slices per animal were evaluated. Area of the lesion and areas of CA3 and hippocampus were measured for each slice (mm2) in the ipsilateral side. The mean lesion area per animal was calculated and normalized to the mean CA3 or hippocampal areas (C, D). Data are expressed as the mean ± SEM of n = 6 animals for each experimental group (two independent experiments with 3 animals in each group). There is no significant difference between the two groups (B: Mann–Whitney test at any time point of recorded seizure score; C and D: Student’s t test).