Fig. 4: The combination of androgens and estrogens in LPC-demyelinated female animals leads to a regeneration process more efficient than the one induced by each molecule used alone.

a Scheme of the experimental paradigm. b–i Visualization of OPC proliferation in b, c, OPC differentiation d, e and MBP immunostaining f, g as well as quantifications carried out 7 days after stereotaxic injection of LPC into the corpus callosum of ovariectomized female mice daily treated with the drug vehicle (Veh), dihydrotestosterone (DHT), estradiol (E2) or the combination of these molecules (DHT + E2). h, i Immunostaining of microglial cells by Iba1 and Arg-1 antibodies for the detection of the whole microglial population and the cell subset expressing the anti-inflammatory marker Arg-1. j–n Scheme of the protocol used for pharmacologically inhibiting the conversion of testosterone to estradiol by using the aromatase inhibitor, fadrozole (Fad) in (j). MBP in (k, l) and Iba1/Arg-1 in (m, n) immunostaining experiments were performed and quantified on slices from the different groups of LPC-demyelinated animals. In (b), the white arrows indicate Ki67⁺ PDGFRα⁺ proliferating OPCs. The dashed lines in (d, f, h, k, m) delineate the lesion. Scale bars (µm): 50 in (b), 100 in (d, f, h, k, m). Data are presented as mean values ± SEM from n = 8 mice/group in (c, e, g, i) examined over two independent experiments and n = 4 mice/group in (l, n) examined in a single experiment (3–4 slices/per animal). P values were calculated by using the one-way ANOVA test together with Tukey’s (c) or Holm-Sidak’s (e, g, l, n) multiple comparisons test or Kruskal-Wallis test together with Dunn’s.multiple comparisons test (i). Brown-Forsythe correction was used for (e left, l). *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ****p ≤ 0.0001 compared to the control (Veh). #p ≤ 0.05; ##p ≤ 0.01; ####p ≤ 0.0001 compared to the indicated condition. Source data are provided as a Source Data file.