Fig. 1
Timeline and quality of slices during culture. A Schematic timeline for the experimental procedure. B Schematic picture of the longitudinal BS-SC and cross-sectional SC slice cultures. C Appearance of longitudinal BS-SC and cross SC sectional slices at 7 (a, d) and 21 (b, e) DIV. In (c) and (f), Cresyl violet staining at 21 DIV of BS-SC and SC slice cultures, respectively, are shown. D The correlation between the total in vitro hOC score and total postfixation Cresyl violet-based hOC score (n = 16 slices from 3 biological cases) is presented. The two total scores were correlated (rs = 0.8440) and linearly distributed (r2 = 0.9353; p < 0.0001). E Total hOC scores of slices cultured under normal conditions at 2, 7, 14, and 21 DIV. F Total hOC score of samples grouped on the basis of their postconceptional week. G The slice area over time in in vitro culture. The area at 7 DIV was considered as 100%. H, I Ki-67 expression in BS-SC slices in in situ and at 21 DIV, respectively. J, K Flow cytometry quantification of proliferating (J) and apoptotic (K) cells in BS-SC slices. L, M Immunostaining for Ki-67 on SC slices in situ (L) and 21 DIV (M). N, O Flow cytometric quantification of proliferating (N) and apoptotic (O) cells in SC slices. The flow cytometry data is presented as the percentage of positive cells out of total cell number. Values are presented as mean ± SEM. Bars: a − c = 2 mm; d − f = 0.5 mm. H, I, L, M = 0.1 mm. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. Abbreviations: BS-SC, longitudinal brain stem-spinal cord slices; SC, spinal cord cross-sectional slices; DIV, days in vitro; n, number of slices (E–G) or biological cases (J, K, N, O)