title: Label-free calcium imaging in ischemic retinal tissue by TOF-SIMS.
abstract: The distribution and movement of elemental ions in biologic tissues is critical for many cellular processes. In contrast to chemical techniques for imaging the intracellular distribution of ions, however, techniques for imaging the distribution of ions across tissues are not well developed. We used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to obtain nonlabeled high-resolution analytic images of ion distribution in ischemic retinal tissues. Marked changes in Ca(2+) distribution, compared with other fundamental ions, such as Na(+), K(+), and Mg(2+), were detected during the progression of ischemia. Furthermore, the Ca(2+) redistribution pattern correlated closely with TUNEL-positive (positive for terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end-labeling) cell death in ischemic retinas. After treatment with a calcium chelator, Ca(2+) ion redistribution was delayed, resulting in a decrease in TUNEL-positive cells. These results indicate that ischemia-induced Ca(2+) redistribution within retinal tissues is associated with the order of apoptotic cell death, which possibly explains the different susceptibility of various types of retinal cells to ischemia. Thus, the TOF-SIMS technique provides a tool for the study of intercellular communication by Ca(2+) ion movement.
authors.affiliation: Neurovascular Coordination Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
authors.forename: Jin Hyoung
authors.initials: JH
authors.lastname: Kim
authors.forename: Jeong Hun
authors.initials: JH
authors.lastname: Kim
authors.forename: Bum Ju
authors.initials: BJ
authors.lastname: Ahn
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Park
authors.forename: Hyun Kyong
authors.initials: HK
authors.lastname: Shon
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Yu
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Moon
authors.forename: Tae Geol
authors.initials: TG
authors.lastname: Lee
authors.forename: Kyu-Won
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012171:Retinal Vessels / Q000378:metabolism* / Q000473:pathology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013194:Staining and Labeling; D014018:Tissue Distribution
chemical_list: D002118:Calcium