Neuropathological differences between rats and mice after spinal cord injury.
OBJECTIVE
To investigate the utility of noninvasive magnetic resonance imaging (MRI) protocols to demonstrate pathological differences between rats and mice after spinal cord injury (SCI). Rats and mice are commonly used to model SCI; however, histology and immunohistochemistry have shown differences in neuropathology between the two species, including cavity formation and scar/inflammatory responses.


METHODS
Moderate contusion SCI was performed on adult male rats and mice. At 28 days postinjury, animals underwent T1-weighted (T1W), with or without gadolinium contrast, or T2-weighted (T2W) magnetic resonance imaging (MRI), to be compared with histology at the same timepoint.


RESULTS
In both species, all MRI methods demonstrated changes in spinal cord anatomy. Immunohistochemistry indicated that T2W accurately reflected areas of inflammation and glial scar formation in rats and mice. Quantitation of lesion volume by histology and functional performance correlated best with T2W measurements in both species. Gadolinium contrast accurately reflected the blood-spinal cord-barrier permeability in both species, which appeared greater in rats than in mice.


CONCLUSIONS
These data demonstrate that MRI, with either a T1W or T2W protocol, can effectively distinguish pathological differences between rats and mice.
Byrnes
Kimberly R
KR
Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA.
Fricke
Stanley T
ST
Faden
Alan I
AI
D000818:Animals; D003287:Contrast Media / Q000494:pharmacology; D005682:Gadolinium / Q000494:pharmacology*; D007150:Immunohistochemistry / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000503:physiopathology*; D013997:Time Factors
D003287:Contrast Media; D005682:Gadolinium