Temporal relationship of peroxynitrite-induced oxidative damage, calpain-mediated cytoskeletal degradation and neurodegeneration after traumatic brain injury.
We assessed the temporal and spatial characteristics of PN-induced oxidative damage and its relationship to calpain-mediated cytoskeletal degradation and neurodegeneration in a severe unilateral controlled cortical impact (CCI) traumatic brain injury (TBI) model. Quantitative temporal time course studies were performed to measure two oxidative damage markers: 3-nitrotyrosine (3NT) and 4-hydroxynonenal (4HNE) at 30 min, 1, 3, 6, 12, 24, 48, 72 h and 7 days after injury in ipsilateral cortex of young adult male CF-1 mice. Secondly, the time course of Ca(++)-activated, calpain-mediated proteolysis was also analyzed using quantitative western-blot measurement of breakdown products of the cytoskeletal protein alpha-spectrin. Finally, the time course of neurodegeneration was examined using de Olmos silver staining. Both oxidative damage markers increased in cortical tissue immediately after injury (30 min) and elevated for the first 3-6 h before returning to baseline. In the immunostaining study, the PN-selective marker, 3NT, and the lipid peroxidation marker, 4HNE, were intense and overlapping in the injured cortical tissue. alpha-Spectrin breakdown products, which were used as biomarker for calpain-mediated cytoskeletal degradation, were also increased after injury, but the time course lagged behind the peak of oxidative damage and did not reach its maximum until 24 h post-injury. In turn, cytoskeletal degradation preceded the peak of neurodegeneration which occurred at 48 h post-injury. These studies have led us to the hypothesis that PN-mediated oxidative damage is an early event that contributes to a compromise of Ca(++) homeostatic mechanisms which causes a massive Ca(++) overload and calpain activation which is a final common pathway that results in post-traumatic neurodegeneration.
Deng
Ying
Y
Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Lexington, KY 40536-0509, USA.
Thompson
Brian M
BM
Gao
Xiang
X
Hall
Edward D
ED
D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001930:Brain Injuries / Q000150:complications* / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002540:Cerebral Cortex / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D003599:Cytoskeleton / Q000473:pathology*; D015227:Lipid Peroxidation; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009410:Nerve Degeneration / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000378:metabolism*; D013049:Spectrin / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D000447:Aldehydes; D009419:Nerve Tissue Proteins; D009566:Nitrates; D013049:Spectrin; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D002154:Calpain; C027576:4-hydroxy-2-nonenal; D002118:Calcium