Experimental delayed postischemic spinal cord hypoperfusion after aortic cross-clamping.
BACKGROUND
As in the brain, recent evidence has suggested a defect in the microcirculation during the reperfusion period after spinal cord ischemia. This investigation was undertaken in order to delineate blood flow dynamics in the postischemic spinal cord of the rat.


METHODS
Male Sprague-Dawley rats underwent cross-clamping of the aorta and subclavian arteries (XC) for 11 minutes. Spinal cord blood flow (SCBF) was measured by autoradiography in the gray and white matter of cervical (Ce), thoracic (Th) and lumbar (Lu) regions during XC, 1 h, 6 h and 24 h (XC n = 8, 1 h n = 9, 6 h n = 9, and 24 h n = 11, groups) after XC. Control groups underwent surgical manipulations and SCBF measurement but no XC (Sham 1, n = 8), or clamping of the subclavian arteries only (Sham 2, n = 8).


RESULTS
In Ce cord, there was no difference between SCBF of 1 h, 6 h, 24 h and Sham 1. In Th cord, SCBF was reduced during XC (P < 0.003 vs. Sham 2), 1 h, 6 h (P < 0.04 and P < 0.01 vs. Sham 1). In Lu cord, SCBF was not detectable in XC, and depressed in 1 h (P < 0.003) and 6 h (P < 0.003). There was no difference between 24 h and Sham 1 in Ce, Th, and Lu cords.


CONCLUSIONS
The study demonstrated a period of delayed postischemic hypoperfusion in the white and gray matter of Th and Lu cord segments lasting 6 h after XC. The phenomenon may play an important role in the ultimate fate of neural elements with borderline viability after ischemic injury.
Follis
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Department of Thoracic and Cardiovascular Surgery, University of New Mexico, Albuquerque 87131, USA.
Miller
K
K
Scremin
O U
OU
Pett
S
S
Kessler
R
R
Temes
T
T
Wernly
J A
JA
D000818:Animals; D001011:Aorta / Q000503:physiopathology; D001783:Blood Flow Velocity; D008297:Male; D017202:Myocardial Ischemia / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013997:Time Factors