Increased production of reactive oxygen species contributes to motor neuron death in a compression mouse model of spinal cord injury.
METHODS
Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury.


OBJECTIVE
To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury.


METHODS
University of Louisville Health Science Center.


METHODS
Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury.


RESULTS
ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury.


CONCLUSIONS
These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.
Xu
W
W
Department of Pediatrics, Kosair Children's Hospital Research Institute, University of Louisville, Louisville, KY 40202, USA.
Chi
L
L
Xu
R
R
Ke
Y
Y
Luo
C
C
Cai
J
J
Qiu
M
M
Gozal
D
D
Liu
R
R
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western / Q000379:methods; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D045304:Cytochromes c / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D007763:Lac Operon / Q000502:physiology; D015227:Lipid Peroxidation / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008958:Models, Molecular; D009046:Motor Neurons / Q000473:pathology*; D016328:NF-kappa B / Q000235:genetics; D010544:Peroxidases; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013119:Spinal Cord Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D013194:Staining and Labeling / Q000379:methods; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1; D013997:Time Factors
D004277:DNA, Single-Stranded; D016328:NF-kappa B; D016760:Proto-Oncogene Proteins c-fos; D017382:Reactive Oxygen Species; C024829:8-hydroxyguanine; D006147:Guanine; D045304:Cytochromes c; D010544:Peroxidases; C437331:dichlorofluorescin peroxidase; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases