title: Green-channel autofluorescence imaging: A novel and sensitive technique to delineate infarcts.
abstract: We have found that infarcted brain regions exhibit green channel autofluorescence (GCAF). Here, we compare ex vivo GCAF-imaging with 2,3,5-triphenylteterazolium chloride (TTC)-staining.
  
  
  
  C57BL/6 mice (n=120) underwent GCAF-imaging after transient or permanent middle cerebral artery occlusion (tMCAO or pMCAO).
  
  
  
  TTC-staining may not reflect subtle ischemic injury. TTC-stained tissues, when reused, are prone to processing artifacts related to prior TTC-staining. GCAF imaging requires little experimental manipulation of animals and brain tissues, and allows for more consistent measurements of infarct volume and reliable reuse of the fresh unstained tissues.
  
  
  
  Lesion volumes measured at 24-h after 1-h tMCAO by using GCAF-images were similar to those using TTC-staining: 87.6±13.6mm3vs. 83.8±12.8mm3in 1mm-thick sections (n=9 mice, 10 slices/mouse, p=0.88; Pearson's r=0.91, p<0.001) and 75.1±7.6mm3vs. 73.6±6.7mm3in 2 mm-thick sections (n=9 mice, 5 slices/mouse, p=0.99; Pearson's r=0.87, p<0.001), respectively. In serial ex vivo imaging performed at 1, 2, 3, 6, 12, and 24-h after tMCAO, GCAF-imaging correlated well with TTC-staining at all time-points. In the pMCAO model however, the correlation was strong at later time-points (6-24-h); but at time points up to 3-h, GCAF-imaging was more sensitive than TTC-staining to detect ischemic areas, as verified by histology, where ischemic damage was observed in the GCAF-positive areas of the cerebral cortex and striatum, even in the face of normal TTC-staining.
  
  
  
  GCAF-imaging is a reliable alternative to TTC-staining in the qualitative and quantitative assessments of focal brain ischemia, and more sensitive for detecting early ischemic damage in pMCAO.
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Kang-Hoon
authors.initials: KH
authors.lastname: Je
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Wi-Sun
authors.initials: WS
authors.lastname: Ryu
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Su-Kyoung
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Pathology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Eo Jin
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Jeong-Yeon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Hee Jeong
authors.initials: HJ
authors.lastname: Jang
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea.
authors.forename: Jung E
authors.initials: JE
authors.lastname: Park
authors.affiliation: Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Matthias
authors.initials: M
authors.lastname: Nahrendorf
authors.affiliation: Departments of Radiology and Cancer Systems Imaging, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Dawid
authors.initials: D
authors.lastname: Schellingerhout
authors.affiliation: Molecular Imaging and Neurovascular Research (MINER) Laboratory, Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea. Electronic address: kdongeog@duih.org.
authors.forename: Dong-Eog
authors.initials: DE
authors.lastname: Kim
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D004396:Coloring Agents; D004195:Disease Models, Animal; D005452:Fluoresceins; D007150:Immunohistochemistry; D008297:Male; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D061848:Optical Imaging / Q000379:methods*; D013778:Tetrazolium Salts
chemical_list: D004396:Coloring Agents; D005452:Fluoresceins; D013778:Tetrazolium Salts; C435731:fluoro jade; C009591:triphenyltetrazolium
keywords: 2,3,5-Triphenyl-tetrazolium chloride staining; Cerebral infarct; Green-channel autofluorescence imaging; Penumbra; Stroke imaging