title: Conditional knockout of CTGF affects corneal wound healing.
abstract: OBJECTIVE
  This study aimed to elucidate the role of connective tissue growth factor (CTGF) in healthy eyes and wounded corneas of mice and rabbits. Conditional knockout mice were used to determine the role of CTGF in corneal healing.
  
  
  METHODS
  CTGF expression was determined using transgenic mice carrying CTGF promoter driven-eGFP, quantitative RT-PCR, and immunofluorescent staining. Mice that carried two floxed CTGF alleles and a Cre/ERT2 transgene under the control of human ubiquitin C (ubc) promoter were used to conditionally delete CTGF gene in a tamoxifen-inducible manner. Phototherapeutic keratectomy (PTK) was used to generate an acute corneal wound and corneal re-epithelialization was assessed by fluorescein staining.
  
  
  RESULTS
  Connective tissue growth factor expression was found in multiple ocular tissues with relatively high levels in the corneal endothelium, lens subcapsular epithelium, and in the vasculature of the iris and retina. Wounded corneas responded with an immediate upregulation of CTGF in the epithelium at the wound margin and a sustained CTGF induction during re-epithelialization. At the onset of haze formation, CTGF protein becomes more focused in the basal epithelium. Deletion of the CTGF gene caused a 40% reduction (P < 0.01) in the cornea re-epithelialization rate in knockout mice compared with wild-type mice.
  
  
  CONCLUSIONS
  Connective tissue growth factor is expressed in the naïve cornea, lens, iris, and retina, and is expressed immediately after epithelial injury. Loss of CTGF impairs efficient re-epithelialization of corneal wounds.
authors.affiliation: Institute for Wound Research, University of Florida, Gainesville, Florida, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gibson
authors.forename: Liya
authors.initials: L
authors.lastname: Pi
authors.forename: Sriniwas
authors.initials: S
authors.lastname: Sriram
authors.forename: Cong
authors.initials: C
authors.lastname: Mao
authors.forename: Bryon E
authors.initials: BE
authors.lastname: Petersen
authors.forename: Edward W
authors.initials: EW
authors.lastname: Scott
authors.forename: Andrew
authors.initials: A
authors.lastname: Leask
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Schultz
mesh_terms: D000818:Animals; D055513:Connective Tissue Growth Factor / Q000096:biosynthesis / Q000235:genetics*; D003315:Cornea / Q000378:metabolism*; D065306:Corneal Injuries; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005131:Eye Injuries / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D012313:RNA / Q000235:genetics*; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014945:Wound Healing / Q000235:genetics*
chemical_list: C526318:CCN2 protein, mouse; D055513:Connective Tissue Growth Factor; D012313:RNA
keywords: CTGF; animal models; pre-fibrosis