Fig. 6

OHdG Immunoreactivity Accumulates in ALS Upper and Lower Motor Neurons and in Glia. a Immunohistochemical staining for OHdG (brown) with cresyl violet counterstaining in aged control motor Kim et al. 29 cortex. Large and small pyramidal neurons (open arrows) have low OHdG immunoreactivity in the nucleus. OHdG immunoreactivity in the neuropil was low. b In ALS motor cortex, many neurons (hatched arrows) were strongly positive for OHdG immunoreactivity (brown, cresyl violet counterstaining). Neuropil OHdG immunoreactivity is augmented compared to control (A). c In aged control ventral horn of spinal cord, motor neurons had prominent Nissl staining (blue, cresyl violet counterstaining) and low OHdG immunoreactivity (brown). Small glial cells showed strong nuclear OHdG immunoreactivity (open arrows, brown). d In ALS spinal cord, ventral horn motor neurons (hatched arrows) were strongly positive for OHdG (brown) as were small glial cells (open arrows). e Aged control spinal motor neurons were large and rich in Nissl substance and had diffusely distributed cytoplasmic OHdG immunoreactivity and modest OHdG immunoreactivity in the nucleus possessing a prominent nucleolus. A nearby glial cell (arrow) was intensely positive for OHdG. f ALS spinal motor neurons were attritional (hatched arrows) with severely dissipated Nissl substance and were enriched in OHdG immunoreactivity in the cytoplasm and nucleus (white asterisks). Many glial cells (open arrows) showed strong OHdG positivity. g-i Single-cell densitometry [111] of OHdG immunoreactivity in pyramidal neurons in motor cortex (G) and primary somatosensory cortex (H) and in ventral horn motor neurons of lumbar and cervical spinal cord of individuals with ALS (n = 16) and AD (n = 10) and aged matched non-neurological disease controls (n = 8). Values are mean ± SD. *p < 0.01. j. Large reactive astrocytes (hatched arrows) in the spinal cord corticospinal tract in ALS cases were strongly positive for OHdG (brown, cresyl violet counterstain). k Large neurons in Clarke’s nucleus (hatched arrows) displayed OHdG immunoreactivity (brown, cresyl violet counterstain) intermediate between control spinal motor neurons (E) and ALS spinal motor neurons (F), though they did appear chromatolytic. Their eccentrically positioned nucleus (white asterisks) had faint OHdG immunoreactivity. l In ALS motor cortex, some lengthy apical dendrites (arrows) of layer five pyramidal neurons were strongly positive for OHdG immunoreactivity. Scale bars (in μm) = 45 (A, same for B), 48 (C, same for D), 12 (E, same for F), 48 (J), 14 (K), 48 (L)