Fig. 1: Effects of rhEPO/placebo on OPC numbers, proliferation, and apoptosis.

a Schematic representation depicting OL differentiation and maturation, along with the respective stage markers. OPC, oligodendrocyte progenitor cells; PreOL, premyelinating oligodendrocytes; COP, committed oligodendrocyte progenitors; Myelinating OL, myelinating oligodendrocytes; NFOL, newly formed oligodendrocytes; MOL, mature myelinating oligodendrocytes. b Experimental design: Starting on P28, wildtype C57Bl/6 mice received rhEPO/placebo intraperitoneally, either once (24 h experiment) or every other day during 1 week or 3 weeks. Mice were sacrificed 24 h after the last injection, in the week 4 experiment after 1 week of break. c Representative images and d quantification of OPC (NG2⁺OLIG2⁺ cells) in CA1 and CA3 following 24 h and 1 week of rhEPO/placebo, respectively. n = 7 mice (CA1 placebo), 6 mice (CA1 rhEPO), 7 mice (CA3 placebo), 6 mice (CA3 rhEPO) for the 24 h timepoint; n = 6 mice for all groups at w1. e Sketch summarizing the course of OPC numbers at 24 h, 72 h, 1 week, and 4 weeks after initiation of rhEPO/placebo treatment. Information on the 72 h and 4 week time point derived from Hassouna et al. 2016. f Representative images and g percentage of proliferative OPC in CA1 at 24 h. n = 6 mice (placebo), 5 mice (rhEPO). h Representative images and i % apoptotic OPC in CA1 at 24 h. n = 6 mice (placebo), 5 mice (rhEPO). Scale bars in c, f, h: 50 µm; mean ± SEM presented; mouse n numbers given in bars; unpaired two-tailed Student’s t-test (d, g, i); a, b, e Created in BioRender. ye, l. (2025) https://BioRender.com/s3nhxid. Source data are provided as a Source Data file.