Detection of focal hypoxic-ischemic injury and neuronal stress in a rodent model of unilateral MCA occlusion/reperfusion using radiolabeled annexin V.
In this study we wished to determine whether technetium-99m annexin V, an in vivo marker of cellular injury and death, could be used to noninvasively monitor neuronal injury following focal middle cerebral artery (MCA) occlusion/reperfusion injury. Sixteen adult male Sprague-Dawley rats (along with four controls) underwent left (unilateral) MCA intraluminal beaded thread occlusion for 2 h followed by reperfusion. One hour following tail vein injection of 5-10 mCi of (99m)Tc-annexin V, animals underwent either single-photon emission computerized tomography (SPECT) or autoradiography followed by immunohistochemical analyses. There was abnormal, bilateral, multifocal uptake of (99m)Tc-annexin V in each cerebral hemisphere as seen by both SPECT and autoradiography at 4 h and 1, 3, and 7 days after initiation of occlusion. The average maximal annexin V uptake at 4 h was 310%+/-85% and 365%+/-151% above control values (P<0.006) within the right and left hemispheres, respectively, peaking on day 3 with values of 925%+/-734% and 1,194%+/-643% (P<0.03) that decreased by day 7 to 489%+/-233% and 785%+/-225% (P<0.01). Total lesional volume of the left hemisphere was 226%, 261%, and 451% ( P<0.03) larger than the right at 4, 24, and 72 h after injury, respectively. Annexin V localized to the cytoplasm of injured neurons ipsilateral to the site of injury as well as to otherwise normal-appearing neurons of the contralateral hemisphere as confirmed by dual fluorescent microscopy. It is concluded that there is abnormal bilateral, multifocal annexin V uptake, greater on the left than on the right side, within 4 h of unilateral left MCA ischemic injury and that the uptake peaks at 3 days and decreases by 7 days after injury. This pattern suggests that neuronal stress may play a role in the response of the brain to focal injury and be responsible for annexin V uptake outside the region of ischemic insult.
Division of Nuclear Medicine, Department of Radiology, Stanford University Hospital, Stanford, CA 94305, USA.
Carina
C
Mari
Murat
M
Karabiyikoglu
Michael L
ML
Goris
Jonathan F
JF
Tait
Midori Anne
MA
Yenari
Francis G
FG
Blankenberg
D000818:Animals; D017304:Annexin A5; D017209:Apoptosis; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000293:injuries / Q000473:pathology; D004195:Disease Models, Animal; D020925:Hypoxia-Ischemia, Brain / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D008297:Male; D009474:Neurons / Q000000981:diagnostic imaging* / Q000473:pathology; D015609:Organotechnetium Compounds; D018384:Oxidative Stress; D019275:Radiopharmaceuticals; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D017304:Annexin A5; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C417036:technetium Tc 99m annexin V