title: Annulus of collagen fibrils in mouse cornea and structural matrix alterations in a murine-specific keratopathy.
abstract: OBJECTIVE
  Mouse corneas were investigated to see whether a limbal annulus of corneal collagen exists as in humans. Mice with corneas predisposed to topographical changes (the SKC strain) were also examined, to establish the size and spacing of stromal collagen fibrils and the integrity of the annulus.
  
  
  METHODS
  X-ray diffraction was used to measure collagen fibril spacing and diameter in normal (the BALB/c strain; four male, two female) and SKC (six male and six female) corneas and to identify the degree of preferred collagen orientation at 200- microm intervals across two BALB/c and four SKC corneas.
  
  
  RESULTS
  The average collagen fibril diameter measured 35.5 nm in 3-month-old BALB/c corneas, and 36.9 nm and 37.0 nm, respectively, in corneas of age-matched male and female SKC mice. In male and female SKC corneas, average collagen interfibrillar Bragg spacing was significantly higher (64.5 and 59.9 nm, respectively) than in corneas of BALB/c mice (49.7 nm). Circumferentially aligned collagen, indicative of a limbal annulus of fibrillar collagen 2.2 mm in diameter, was identified in mouse cornea. On occasion, this was disturbed in the SKC phenotype.
  
  
  CONCLUSIONS
  Collagen fibrils are marginally larger in the corneas of SKC mice than in the corneas of BALB/c mice and are considerably more widely spaced. An annulus of fibrillar collagen probably exists near the limbus of the normal mouse cornea that may help promote biomechanical stability and maintain corneal shape. A loss of structural integrity in the annulus of some SKC mice may predispose the corneas to biomechanical instability and shape changes.
authors.affiliation: Structural Biophysics Group, Department of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom. quantockaj@cf.ac.uk
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Quantock
authors.forename: Sally
authors.initials: S
authors.lastname: Dennis
authors.forename: Wakako
authors.initials: W
authors.lastname: Adachi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Craig
authors.initials: C
authors.lastname: Boote
authors.forename: Keith M
authors.initials: KM
authors.lastname: Meek
authors.forename: Yoshibumi
authors.initials: Y
authors.lastname: Matsushima
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tachibana
mesh_terms: D000818:Animals; D003094:Collagen / Q000032:analysis*; D003315:Cornea / Q000737:chemistry*; D003316:Corneal Diseases / Q000150:complications*; D005109:Extracellular Matrix / Q000737:chemistry; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D014961:X-Ray Diffraction
chemical_list: D003094:Collagen