title: Corneal wound healing after ultraviolet-A/riboflavin collagen cross-linking: a rabbit study.
abstract: OBJECTIVE
  To investigate corneal wound healing following ultraviolet-A (UVA)/riboflavin corneal collagen cross-linking (CXL) in rabbit corneas.
  
  
  METHODS
  Thirty-six rabbits were enrolled in the study. Animals were divided into three treatment groups and corneas were analyzed at 24 hours and 4 weeks postoperatively. Thus, each group had 6 rabbits at each time point. Treatment groups were: 1) standard UVA+riboflavin CXL, 2) UVA alone, and 3) riboflavin alone. One eye of each rabbit served as an untreated control eye. TUNEL assay was performed to detect stromal cell apoptosis. Immunocytochemistry was performed to detect the inflammatory marker CD11b expressed in monocytes and the alpha-smooth muscle actin (SMA) marker expressed in myofibroblasts.
  
  
  RESULTS
  At 24 hours, corneas from the UVA+riboflavin CXL group had significantly more apoptosis than the UVA alone and riboflavin alone groups. Eyes from all three groups had significantly more inflammatory cell influx into the cornea than unwounded controls. Four weeks after the procedure, many corneas in the UVA+riboflavin CXL group had mild haze, but very few SMA-positive myofibroblasts could be detected in the central cornea.
  
  
  CONCLUSIONS
  Riboflavin+UVA CXL triggers more anterior keratocyte apoptosis than corneal scrape with UVA alone or riboflavin alone. Inflammation monitored by the monocyte marker CD11b was present, but not statistically different among the three groups. Very little myofibroblast generation could be detected after UVA+riboflavin CXL, indicating that the mild stromal haze associated with this procedure is normally related to transient corneal fibroblast generation rather than more persistent haze due to generation of myofibroblasts.
authors.affiliation: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Marcella Q
authors.initials: MQ
authors.lastname: Salomão
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Chaurasia
authors.forename: Abhijit
authors.initials: A
authors.lastname: Sinha-Roy
authors.forename: Renato
authors.initials: R
authors.lastname: Ambrósio
authors.forename: Andrew
authors.initials: A
authors.lastname: Esposito
authors.forename: Ricardo
authors.initials: R
authors.lastname: Sepulveda
authors.forename: Vandana
authors.initials: V
authors.lastname: Agrawal
authors.forename: Steven E
authors.initials: SE
authors.lastname: Wilson
mesh_terms: D000818:Animals; D017209:Apoptosis; D039481:CD11b Antigen / Q000096:biosynthesis; D003094:Collagen / Q000627:therapeutic use*; D003319:Corneal Stroma / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005131:Eye Injuries / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D005260:Female; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D009000:Monocytes / Q000378:metabolism / Q000473:pathology; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011817:Rabbits; D012256:Riboflavin / Q000627:therapeutic use*; D016896:Treatment Outcome; D014467:Ultraviolet Therapy / Q000379:methods*; D014945:Wound Healing
chemical_list: D039481:CD11b Antigen; D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin