title: Iontophoresis Transcorneal Delivery Technique for Transepithelial Corneal Collagen Crosslinking With Riboflavin in a Rabbit Model.
abstract: OBJECTIVE
  We compared an iontophoresis riboflavin delivery technique for transepithelial corneal collagen crosslinking (I-CXL) with a conventional CXL (C-CXL).
  
  
  METHODS
  We designed three experimental sets using 152 New Zealand rabbits to study riboflavin application by iontophoresis using charged riboflavin solution (Ricrolin+) with a 1-mA current for 5 minutes. The first set was to compare riboflavin concentration measured by HPLC in corneas after iontophoresis or conventional riboflavin application. The second set was to analyze autofluorescence and stromal collagen modification immediately and 14 days after I-CXL or C-CXL, by using nonlinear two-photon microscopy (TP) and second harmonic generation (SHG). In the third set, physical modifications after I-CXL and C-CXL were evaluated by stress-strain measurements and by studying corneal resistance against collagenase digestion.
  
  
  RESULTS
  Based on HPLC analysis, we found that iontophoresis allowed riboflavin diffusion with 2-fold less riboflavin concentration than conventional application (936.2 ± 312.5 and 1708 ± 908.3 ng/mL, respectively, P < 0.05). Corneal TP and SHG imaging revealed that I-CXL and C-CXL resulted in a comparable increased anterior and median stromal autofluorescence and collagen packing. The stress at 10% strain showed a similar stiffness of corneas treated by I-CXL or C-CXL (631.9 ± 241.5 and 680.3 ± 216.4 kPa, respectively, P = 0.908). Moreover, we observed an increased resistance against corneal collagenase digestion after I-CXL and C-CXL (61.90% ± 5.28% and 72.21% ± 4.32% of remaining surface, respectively, P = 0.154).
  
  
  CONCLUSIONS
  This experimental study suggests that I-CXL is a promising alternative methodology for riboflavin delivery in crosslinking treatments, preserving the epithelium.
authors.affiliation: Department of Ophthalmology Purpan Hospital, Toulouse, France 2Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresde.
authors.forename: Myriam
authors.initials: M
authors.lastname: Cassagne
authors.affiliation: Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresden, Germany 5INSERM U1043, Center of Physiopathology, Dynamique.
authors.forename: Camille
authors.initials: C
authors.lastname: Laurent
authors.affiliation: Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresden, Germany 5INSERM U1043, Center of Physiopathology, Dynamique.
authors.forename: Magda
authors.initials: M
authors.lastname: Rodrigues
authors.affiliation: Department of Biochemistry, Rangueil Hospital, Toulouse, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Galinier
authors.affiliation: Department of Ophthalmology, Technische Universität Dresden, Dresden, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Spoerl
authors.affiliation: Department of Ophthalmology Purpan Hospital, Toulouse, France 2Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresde.
authors.forename: Stéphane D
authors.initials: SD
authors.lastname: Galiacy
authors.affiliation: Department of Ophthalmology Purpan Hospital, Toulouse, France 2Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresde.
authors.forename: Vincent
authors.initials: V
authors.lastname: Soler
authors.affiliation: Department of Ophthalmology Purpan Hospital, Toulouse, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Fournié
authors.affiliation: Department of Ophthalmology Purpan Hospital, Toulouse, France 2Laboratory of Pathology, Purpan Hospital, Toulouse, France 3Department of Biochemistry, Rangueil Hospital, Toulouse, France 4Department of Ophthalmology, Technische Universität Dresden, Dresde.
authors.forename: François
authors.initials: F
authors.lastname: Malecaze
mesh_terms: D000818:Animals; D003094:Collagen / Q000008:administration & dosage*; D003432:Cross-Linking Reagents; D004195:Disease Models, Animal; D019573:Epithelium, Corneal; D005260:Female; D007478:Iontophoresis / Q000379:methods*; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011817:Rabbits; D012256:Riboflavin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D003432:Cross-Linking Reagents; D014803:Vitamin B Complex; D003094:Collagen; D012256:Riboflavin