title: (99m)Tc-Annexin-V uptake in a rat model of variable ischemic severity and reperfusion time.
abstract: BACKGROUND
  To determine whether mild to moderate ischemia that is not severe enough to induce myocardial infarction will cause myocardial cell damage or apoptosis, the (99m)Tc-Annexin-V (Tc-A) uptake was studied in groups of rats with various intervals of coronary occlusion and reperfusion times.
  
  
  RESULTS
  After left coronary artery occlusion for 15 min (n=23), 10 min (n=23), or 5 min (n=12), Tc-A (80-150 MBq) was injected at 0.5, 1.5, 6, or 24 h after reperfusion. One hour later, to verify the area at risk, (201)Tl (0.74 MBq) was injected just after left coronary artery re-occlusion and the rats were killed 1 min later. Dual tracer autoradiography was performed to assess Tc-A uptake and area at risk. In all 5-min occlusion and reperfusion models, no significant Tc-A uptake was observed in the area at risk. Tc-A uptake ratios in the 15-min and 10-min ischemia models were 4.46+/-3.16 and 2.02+/-0.47 (p=0.078) at 0.5 h after reperfusion, 3.49+/-1.78 and 1.47+/-0.11 (p<0.05) at 1.5 h after reperfusion, 1.60+/-0.43 and 1.34+/-0.23 (p=0.24) at 6 h after reperfusion, 1.50+/-0.33 and 1.28+/-0.33 (p=0.099) at 24 h after reperfusion, respectively. With 15-min ischemia, in 3 of the 5 rats there were a few micro-foci of myocardial cell degeneration and cell infiltration in less than 1% of the ischemic area at 24 h after reperfusion. No significant histological change was observed in rats with 10-min or 5-min ischemia.
  
  
  CONCLUSIONS
  The data indicate that Tc-A binding depends on the severity of ischemia even without a significant amount of histological change or infarction.
authors.affiliation: Department of Biotracer Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan. taki@med.kanazawa-u.ac.jp
authors.forename: Junichi
authors.initials: J
authors.lastname: Taki
authors.forename: Takahiro
authors.initials: T
authors.lastname: Higuchi
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kawashima
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: Tait
authors.forename: Akira
authors.initials: A
authors.lastname: Muramori
authors.forename: Ichiro
authors.initials: I
authors.lastname: Matsunari
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nakajima
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Vanderheyden
authors.forename: H William
authors.initials: HW
authors.lastname: Strauss
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000493:pharmacokinetics*; D017209:Apoptosis; D001345:Autoradiography; D004195:Disease Models, Animal; D020287:In Situ Nick-End Labeling; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism* / Q000473:pathology*; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D017304:Annexin A5; D015609:Organotechnetium Compounds; C417036:technetium Tc 99m annexin V