Fig. 1

During development, ketamine-induced apoptosis follows the lamination pattern of physiological apoptosis. a Representative confocal images of coronal S1 sections immunolabelled for CC3 (green), and co-stained for nuclei with TOPRO (red) to visualize cortical lamination. Age and treatment conditions as indicated. Cortical layers are indicated by Roman numerals, and borders between cortical layers marked using dotted lines. Scale bar is 200 μm. b Quantitation of the number of CC3⁺ cells per mm² S1, age and treatment conditions as indicated. PBS and PBS# conditions respectively represent pups injected with PBS and kept away from or together with their mothers during the experiment. Dex, Keta and Keta + Dex respectively represent pups injected with dexmedetomidine, ketamine or ketamine plus dexmedetomidine. All conditions compared to PBS condition of the same age, ^** P < 0.01, ^*** P < 0.001, using one-way ANOVA followed by Dunnett’s multiple comparisons test. (c-f) Distribution of the proportion of CC3⁺ cells in different cortical layers at P5 (c), P7 (d), P9 (e) and P12 (f). In all age groups, the percentage of CC3⁺ neurons in layers II – IV, layer V, or other layers (layer I and layer VI) in the Keta group or Keta + Dex group were not significantly different from that of the PBS control group. P > 0.05, using two-way ANOVA followed by Bonferroni post hoc tests. (g) Replot of the data presented in (c-f) for the PBS, Keta, and Keta + Dex groups, showing developmental changes in apoptosis pattern. ^** P < 0.01, ^*** P < 0.001, using two-way ANOVA followed by Bonferroni post hoc tests. 3–5 mice were used per condition, 10 brain slices from each mouse were quantitated. Data are shown as the mean ± SEM