title: Structural modifications and tissue response after standard epi-off and iontophoretic corneal crosslinking with different irradiation procedures.
abstract: OBJECTIVE
  The aim of this study is to investigate modifications in human cadaver corneas after different crosslinking procedures, including standard epi-off treatment, iontophoresis imbibition, and different exposure to ultraviolet A (UVA) sources (30 minutes at 3 mW and 9 minutes at 10 mW).
  
  
  METHODS
  A total of 12 human cadaver corneas was examined and divided as follows: 3 served as control (group 1), 3 were treated with a standard epi-off procedure (group 2), 6 underwent iontophoresis imbibition for 5 minutes, and then 3 were irradiated for 30 minutes with 3 mW UVA (group 3), and 3 for 9 minutes at 10 mW UVA (group 4). Deformation amplitude index was measured before and after the corneas underwent treatment. After treatment, corneas were prepared for hematoxylin-eosin and immunohistochemistry evaluation. The expression of TUNEL, matrix metalloproteinase-1 (MMP-1), collagen type I, and CD34 was investigate in all samples.
  
  
  RESULTS
  The deformation amplitude index decreased in all groups, in particular in group 4, indicating an improvement of corneal biomechanical properties. Immunohistochemical staining showed a significant stromal alteration in group 2, mild damage in group 3, and no modifications in corneal morphology in group 4. The TUNEL (P < 0.001) and MMP-1 (P = 0.002) positivity was more evident in group 4. Collagen type I positivity significantly increased in groups 3 (P = 0.002) and 4 (P = 0.002). The CD34 expression was more evident in groups 2 (P = 0.003) and 3 (P = 0.003).
  
  
  CONCLUSIONS
  Iontophoresis imbibition followed by UVA irradiation for 9 minutes at 10 mW determined less tissue damage and better stromal remodeling.
authors.affiliation: Department of Medicine and Ageing Sciences, Ophthalmology Clinic, University "G. d'Annunzio" of Chieti-Pescara, Chieti and Pescara, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mastropasqua
authors.forename: Manuela
authors.initials: M
authors.lastname: Lanzini
authors.forename: Claudia
authors.initials: C
authors.lastname: Curcio
authors.forename: Roberta
authors.initials: R
authors.lastname: Calienno
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Mastropasqua
authors.forename: Martina
authors.initials: M
authors.lastname: Colasante
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mastropasqua
authors.forename: Mario
authors.initials: M
authors.lastname: Nubile
mesh_terms: D002102:Cadaver; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D007478:Iontophoresis / Q000379:methods*; D007640:Keratoconus / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen
keywords: crosslinking; iontophoresis; keratoconus