title: Ultrastructural examination of corneal epithelium of spontaneously obese, hyperglycemic rats.
abstract: OBJECTIVE
  Otsuka Long-Evans Tokushima fatty (OLETF) rats spontaneously become obese and hyperglycemic with age. We investigated whether the development of hyperglycemia would alter the ultrastructure of the corneal epithelium.
  
  
  METHODS
  Scanning and transmission electron microscopy (SEM and TEM) were used to examine the morphology of corneal epithelial cells. Fourteen OLETF rats were evaluated, and 9 Long-Evans Tokushima Otsuka (LETO) rats were used as control. Non-hyperglycemic OLETF rats served as controls.
  
  
  RESULTS
  SEM showed exfoliative changes in the surface of the central corneal epithelium of the hyperglycemic OLETF rats. These superficial epithelial cells were irregular in shape as compared to polygonal shapes of those of LETO and non-hyperglycemic OLETF rats. The mean anterior surface area of individual superficial epithelial cells was significantly smaller in the hyperglycemic OLETF than that of the LETO or the non-hyperglycemic OLETF rats. Central protrusion(s) could be found in some of the superficial cells of all rats examined, although this phenomenon was more common in the hyperglycemic rats than in the non-hyperglycemic rats. TEM revealed that there were numerous cytoplasmic vacuoles and wide intercellular spaces in the central corneal epithelium of the hyperglycemic OLETF rats, but not in the non-hyperglycemic rats.
  
  
  CONCLUSIONS
  The development of spontaneous hyperglycemia in OLETF rats alters the ultrastructure of the corneal epithelium. The alterations included abnormalities of the corneal epithelial surface observed by SEM and the presence of intracellular vacuoles and enlarged intercellular spaces detected by TEM.
authors.affiliation: Department of Ophthalmology, Wakayama Medical College, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Saika
authors.forename: M
authors.initials: M
authors.lastname: Shimezaki
authors.forename: K
authors.initials: K
authors.lastname: Ohkawa
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: A
authors.initials: A
authors.lastname: Tawara
authors.forename: Y
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: A
authors.initials: A
authors.lastname: Ooshima
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: N
authors.initials: N
authors.lastname: Kurumatani
authors.forename: H
authors.initials: H
authors.lastname: Naka
authors.forename: T
authors.initials: T
authors.lastname: Awata
authors.forename: W W
authors.initials: WW
authors.lastname: Kao
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D019573:Epithelium, Corneal / Q000648:ultrastructure*; D005260:Female; D006943:Hyperglycemia / Q000473:pathology*; D007365:Intercellular Junctions / Q000648:ultrastructure; D008297:Male; D008855:Microscopy, Electron, Scanning; D009765:Obesity / Q000473:pathology*; D051381:Rats; D020334:Rats, Inbred OLETF; D014617:Vacuoles / Q000648:ultrastructure