title: Simultaneous in vivo imaging of leukocyte migration: heterogeneity among iris, limbus, and choroid vessels.
abstract: OBJECTIVE
  Endothelial cells of different vascular systems may express site-specific adhesion molecules to attract leukocyte subsets. This study describes a method to visualize and compare leukocyte-endothelial interactions in three vascular beds within the same eye in mice.
  
  
  METHODS
  Digital in vivo fluorescence microscopy was used to record a trans-corneal iris view, a superficial limbus view, and a trans-scleral anterior choroid view of mouse tissue. Uveitis was induced by intravitreal injection of E. coli endotoxin into BALB/c mice. Leukocytes were labeled systemically with SYTO-16 or rhodamine 6G. Leukocyte rolling and sticking were quantified at baseline and 4, 6, and 24 hours after endotoxin injection.
  
  
  RESULTS
  In a normal animal, the limbus had 18 times the number of rolling leukocytes and 6 times the number of sticking leukocytes relative to the iris. All three vascular beds were affected by intravitreal injection of endotoxin. Although they each showed increased numbers of rolling and sticking cells, the levels and kinetics of these increases differed. Rolling peaked at 6 hours in the iris (34-fold increase from baseline) and limbus (7-fold increase) but was maximal in the choroid earlier with a 16-fold increase. Sticking was maximal at 4 hours for iris (96-fold increase) and choroid (19-fold increase) but peaked in the limbus at 6 hours (47-fold increase from baseline).
  
  
  CONCLUSIONS
  This study demonstrates that leukocyte-endothelial dynamics are not the same in different vascular beds in the normal mouse eye. Furthermore, site-specific differences in responses to intravitreally injected endotoxin, beyond what can be readily explained by differential distribution of endotoxin, were observed. The methodology can be used to test the hypothesis that endothelial cells within the eye have site-specific patterns of adhesion molecule expression.
authors.affiliation: Casey Eye Institute, Oregon Health Sciences University, Portland 97201, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Rosenbaum
authors.forename: M
authors.initials: M
authors.lastname: Brischetto
authors.forename: S
authors.initials: S
authors.lastname: Crespo
authors.forename: M
authors.initials: M
authors.lastname: Bierwirth
authors.forename: K
authors.initials: K
authors.lastname: Oveson
authors.forename: S R
authors.initials: SR
authors.lastname: Planck
authors.forename: M D
authors.initials: MD
authors.lastname: Becker
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000502:physiology; D002829:Choroid / Q000098:blood supply*; D004731:Endotoxins / Q000494:pharmacology; D005260:Female; D007091:Image Processing, Computer-Assisted; D007498:Iris / Q000098:blood supply*; D036904:Leukocyte Rolling / Q000187:drug effects; D007962:Leukocytes / Q000502:physiology*; D016850:Limbus Corneae / Q000098:blood supply*; D051379:Mice; D008807:Mice, Inbred BALB C; D008833:Microcirculation; D008856:Microscopy, Fluorescence; D012016:Reference Values; D014605:Uveitis / Q000139:chemically induced / Q000503:physiopathology
chemical_list: D004731:Endotoxins