Fig. 7.

DNA Damage Coincides with Cell Death Markers in ALS Motor Neurons. a Spinal motor neurons in ALS showed colocalization of activated p53 (brown) and accumulated OHdG (black/dark green). Dual antigen labeling was done using DAB (brown) and BDHC (black/dark green) as chromogens [30] to avoid the pitfalls of immunofluorescence in aged postmortem human CNS tissues [45]. Colocalization was present in the nucleus Kim et al. 30 (hatched arrow) and in cytoplasmic particles. b Spinal motor neurons in ALS showed colocalization of accumulated OHdG (brown) and cleaved caspase-3 (black/dark green). c-d Cortical pyramidal neurons showed colocalization of accumulated OHdG (brown) and cleaved caspase-3 (black/dark green) and different neurons showed OHdG immunoreactivity in nuclear subdomains. In some neurons (C, hatched arrow), the nuclear OHdG immunoreactivity was mostly homogenous, but in other neurons (E, D) nuclear OHdG immunoreactivity was seen as granular particles (D, hatched arrow) and perinucleolar decorations (E, hatched arrow). Some cortical pyramidal neurons showed cleaved caspase-3 immunoreactivity but not OHdG immunoreactivity (D, solid arrow). f Spinal motor neurons in the chromatolytic pre-attritional stage of degeneration [63] in ALS cases showed perikaryal cytoplasmic enrichment of cleaved caspase-3 (black/dark green) and mitochondria (brown), identified by cytochrome c oxidase subunit 1 (Cox1) immunoreactivity, but the eccentrically placed nucleus was devoid of cleaved caspase-3 positivity (hatched arrow). Insets: different cytoplasmic regions where cleaved caspase-3 (black/dark green) is in association with discrete mitochondria (brown). g Spinal motor neurons (hatched arrow) in the attritional stage of degeneration [63] in ALS cases showed nuclear enrichment of cleaved caspase-3 (black/dark green) and cytoplasmic accumulation of mitochondria (brown). Scale bars (in μm) = 33 (A), 20 (B), 12 (C-D), 7 (F) 3 (F inset top), 2.5 (F inset bottom), 8 (G)