title: Effect of 1- and 6-Hour-Delayed Corneal Collagen Cross-Linking on Corneal Healing in a Rabbit Alkali-Burn Model: Clinical and Histological Observations.
abstract: OBJECTIVE
  To study the effect of 1- and 6-hour-delayed corneal collagen cross-linking (CXL) on wound-healing of experimental alkali burns of the cornea.
  
  
  METHODS
  Twenty-four albino rabbits were used. Alkali burns were created using 1 M NaOH. The animals were divided randomly into 2 groups: group 1 (control group, n = 6) and group 2 (experimental group, n = 18). The experimental group was further divided into 3 subgroups as follows: group 2A, untreated (non-CXL) subgroup; group 2B, 1-hour-delayed CXL treatment subgroup; and group 2C, 6-hour-delayed CXL treatment subgroup. All rabbits were examined periodically for 21 days after treatment and then killed. The corneas were excised and histologically examined.
  
  
  RESULTS
  Corneal ulceration, edema, and opacity scores were 4.0 ± 1.64, 1.6 ± 0.65, and 3.5 ± 1.21 in group 2A, 1.5 ± 1.76, 1.3 ± 0.87, and 3.1 ± 1.12 in group 2B, and 2.0 ± 1.90, 1.5 ± 0.79, and 3.3 ± 1.09 in group 2C, respectively. These scores were significantly less in groups 2B and 2C than in group 2A (P = 0.023, P = 0.043, and P = 0.034, respectively). Corneal epithelialization, evident upon staining, was best in group 2B and worst in group 2A (P = 0.012). Histopathology revealed that destruction of corneal collagen fibers and infiltration of inflammatory cells into corneal tissue were reduced in groups 2B and 2C compared with group 2A.
  
  
  CONCLUSIONS
  We found that CXL treatment exerted positive effects on severe alkali-induced corneal burns. However, the effects were more pronounced in the 1-hour treatment group. We believe that CXL treatment may be a possible treatment for corneal alkali burn.
authors.affiliation: *Department of Ophthalmology, Bozyaka Training and Research Hospital, Izmir, Turkey;†Department of Ophthalmology, Izmir University, Izmir, Turkey;‡Department of Histology and Embryology, Dokuz Eylul University, Izmir, Turkey;§West Eye Hospital, Izmir, Turkey; and¶Department of Laboratory Animal Science, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey.
authors.forename: Omer
authors.initials: O
authors.lastname: Karti
authors.forename: Mehmet Ozgur
authors.initials: MO
authors.lastname: Zengin
authors.forename: Esat
authors.initials: E
authors.lastname: Cinar
authors.forename: Merve
authors.initials: M
authors.lastname: Tutuncu
authors.forename: Eyyup
authors.initials: E
authors.lastname: Karahan
authors.forename: Asl
authors.initials: A
authors.lastname: Celik
authors.forename: Cem
authors.initials: C
authors.lastname: Kucukerdonmez
mesh_terms: D000818:Animals; D002057:Burns, Chemical / Q000188:drug therapy* / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D003316:Corneal Diseases / Q000188:drug therapy* / Q000378:metabolism; D003319:Corneal Stroma / Q000378:metabolism; D003432:Cross-Linking Reagents; D004195:Disease Models, Animal; D019573:Epithelium, Corneal / Q000502:physiology; D005126:Eye Burns / Q000139:chemically induced*; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011817:Rabbits; D062326:Re-Epithelialization / Q000502:physiology; D012256:Riboflavin / Q000627:therapeutic use; D012972:Sodium Hydroxide; D013997:Time Factors; D014466:Ultraviolet Rays; D014945:Wound Healing / Q000502:physiology*
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D012972:Sodium Hydroxide; D003094:Collagen; D012256:Riboflavin