Figure 1. Neonatal HX increases Sirt1 expression in OPCs of the white matter.

(a) NAD level in white matter after NX and HX expressed in optical density (OD) units. Mean±s.e.m., four independent experiments, two brains per condition measured in triplicate. (b) Levels of histone deacetylases class I+II and III in white matter in NX and HX expressed in pmol l⁻¹ (pM). Mean±s.e.m., two independent experiments, three brains per condition in triplicate. (c) Representative western blot of Sirt1, and pSirt1 Ser47 and pSirt1 Ser27 in NX and HX white matter (P18).(d) Confocal images of Sirt1⁺ cells in NX and HX white matter in WT and CNP-EGFP mice. Dotted lines delineate white matter. WM, white matter. Scale bar, 100 μm. Arrows indicate magnified cells. HX increases Sirt1⁺ cells (e), proliferating Sirt1⁺ (f), NG2⁺Sirt1⁺ (g) and NG2⁺Sirt1⁺BrdU⁺ (h) cells in white matter. Mean±s.e.m. Number of samples indicated in parentheses, n=4 brains per condition. (i) Semi-quantitative RT–PCR analysis of Sirt1, Olig2 and MBP mRNAs from purified NG2⁺EGFP⁺ progenitors and NG2negEGFP⁺ OLs.