Fig. 2: Reduced Sirt2 expression in subcortical WM of preterm infants.

a Tissue sections from the corpus callosum of preterm human neonates and term controls were analyzed. H&E image shows lower magnification of corpus callosum region analyzed for preterm and term controls. Scale bar = 100 µm. b Representative H&E photomicrographs of corpus callosum (n = 4 term and 4 preterm). In term controls, well-defined OLs with well-defined nucleolus (arrow) and dense neuropil were observed (arrowhead). In contrast, in preterm neonates (right panels) hypodense and rarefied neuropil were present (arrowhead) with OLs that appear edematous and vacuolated (arrow). Scale bars = 50 µm for upper panels and 20 µm for lower panels. c Olig2⁺ immunostaining (green) in WM of term and preterm neonates. Scale bars = 50 µm. d, e Quantification of the density d and the percentage of Olig2⁺ cells e in term and preterm neonates. (**p = 0.005, *p = 0.026, n = 4 term and 3 preterm, Student’s t test). f Low magnification images of Sirt2⁺ immunostaining (red) in WM of term and preterm neonates. Scale bars = 50 µm. g Quantification of the intensity of Sirt2 staining in term and preterm neonates (*p = 0.017, n = 4 term and 3 preterm, Student’s t test). h Quantification of the percent area of Sirt2⁺ signal in the WM of term and preterm neonates (*p = 0.014, n = 4 term and 3 preterm, Student’s t test). i Sirt2 expression within WM Olig2⁺ cells of term and preterm neonates. Bottom panels show magnified single-channel images for Olig2 (green) and Sirt2 (red) to highlight cytoplasmic localization of Sirt2. Scale bars = 10 µm. j Quantification of the density of Sirt2⁺Olig2⁺ cells in term and preterm neonates (*p = 0.01, n = 4 term and 3 preterm, Student’s t test). k Quantification of the percentage of Sirt2⁺ oligodendrocytes in term and preterm neonates (*p = 0.011, n = 4 term and 3 preterm, Student’s t test). H&E, Hematoxylin and Eosin. Data are represented as mean ± SEM. All statistical tests are two-sided. Source data are provided as a Source Data file. The human brain schematic in a was created using Servier Medical Art templates, which are licensed under a Creative Commons Attribution 3.0 Unported License.