FIGURE 1.

Age-dependent increase in oxidative stress in WT Pvalb neurons evidenced by 8-oxo-dG staining. (A) Sagittal brain section from a 3-month old WT mouse stained for 8-oxo-dG (oxidative stress marker, red), EGFP (Pvalb neurons expressing EGFP, green) and DAPI (nuclei, blue). Regions with strong 8-oxo-dG staining (white boxes in low-left image in A) –hippocampus, TRN, MVN and cerebellum– are shown at higher magnification in (B). Note the higher densities of EGFP⁺ Pvalb neurons and/or neuropil (fibers) in these regions resulting in partial yellow staining in the merged images. Scale bar in (A) 1 mm, in (B) 200 μm. Sagittal brain sections scanned by the NanoZoomer serve for demonstration purposes and were not analyzed in the study. (C) Quantitative analyses were performed on confocal microscopy images. Brain sections were scanned in nine regions – 3 hippocampal regions (CA1, CA3, and DG), striatum, SSC, mPFC, 2 cerebellar regions [Purkinje cell layer (PC) and in molecular layer interneurons (MLI)] and TRN. Fluorescence signal quantifications were carried out in 1, 3, and 6-months old mice [normalized values (mean ± SD) are reported in Table 1]; for clarity, error bars and regression lines are omitted; R² values are from linear regression analyses using the three time points: 1, 3, and 6 months and are listed in Table 1.