Evolution of spinal cord injury in a porcine model of prolonged aortic occlusion.
BACKGROUND
Spinal cord injury and subsequent paraplegia remains an unpredictable and devastating complication of thoracoabdominal aortic surgery. The aim of this study was to investigate spinal cord injury due to prolonged thoracoabdominal aortic occlusion.


METHODS
We used a highly reproducible porcine model of 45-min thoracoabdominal aortic occlusion, which was accomplished by two balloon occlusion catheters. Neurological evaluation after the end of experiment was performed by an independent observer according to the Tarlov scale. The lower thoracic and lumbar spinal cords were harvested at 10, 48, and 120 h (n = 6 animals per time point) and examined histologically with hematoxylin and eosin (H&E) stain and TUNEL method. Tarlov scores, number of neurons, and the grade of inflammation were analyzed.


RESULTS
H&E staining revealed reduction in the number of motor neurons which occurred in two phases (between 0 and 10 h and between 48 and 120 h of reperfusion), as well as development of inflammation in spinal cord sections during the reperfusion period, reaching a peak at 48 h. TUNEL reaction was negative for apoptotic neurons at any time point.


CONCLUSIONS
In this porcine model, we demonstrated that, after 45 min of thoracoabdominal aortic occlusion, motor neuron death seems to occur in two phases (immediate and delayed). Inflammation was a subsequent event of transient prolonged spinal cord ischemia and possibly a major contributor of delayed neuronal death. Using TUNEL straining we found no evidence of neuronal apoptosis at any time point of reperfusion.
Papakostas
John C
JC
Department of Surgery, Vascular Surgery Unit, School of Medicine, University of Ioannina, Ioannina, Greece.
Matsagas
Miltiadis I
MI
Toumpoulis
Ioannis K
IK
Malamou-Mitsi
Vasiliki D
VD
Pappa
Lina S
LS
Gkrepi
Constantina
C
Anagnostopoulos
Constantine E
CE
Kappas
Angelos M
AM
D000005:Abdomen / Q000601:surgery*; D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery; D001013:Aorta, Thoracic / Q000601:surgery; D001157:Arterial Occlusive Diseases / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D001794:Blood Pressure; D002470:Cell Survival; D004195:Disease Models, Animal; D005260:Female; D020287:In Situ Nick-End Labeling; D007431:Intraoperative Complications / Q000276:immunology / Q000473:pathology*; D007511:Ischemia / Q000209:etiology / Q000473:pathology; D008214:Lymphocytes / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008297:Male; D009046:Motor Neurons / Q000473:pathology; D009187:Myelitis / Q000209:etiology / Q000276:immunology / Q000473:pathology; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000098:blood supply* / Q000276:immunology / Q000473:pathology; D013118:Spinal Cord Diseases / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D013525:Surgical Instruments; D013552:Swine; D013997:Time Factors