title: Longitudinal Changes to Tight Junction Expression and Endothelial Cell Integrity in a Mouse Model of Sterile Corneal Inflammation.
abstract: We previously reported that applying toll-like receptor (TLR) ligands to an injured cornea induces corneal edema at 24 hours, which subsides by 1 week. We tested the hypotheses that endothelial expression of the tight-junction protein, zonula occludens-1 (ZO-1), would be altered during experimental sterile corneal inflammation and that endothelial cell density (ECD) would remain unaffected.
  
  
  
  Anesthetized C57BL/6J mice received central 1-mm corneal abrasions followed by topical application of saline or cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN, TLR-9 agonist). At 24 hours, 1 week and 4 weeks post treatment, spectral-domain optical coherence tomography images were captured. Eyes were enucleated and processed for zonula occludens-1 (ZO-1) immunofluorescent staining. Corneal flatmounts were analyzed for endothelial ZO-1 expression, cell density, polymegethism, and polymorphism. Corneal stromal inflammatory cell infiltration was evaluated at 4 weeks by immunostaining for CD45.
  
  
  
  Central corneal thickness (CCT) was increased in CpG-ODN treated eyes at 24 hours, had normalized by 1 week, but was again thickened by 4 weeks. In eyes with CpG-ODN, endothelial cell ZO-1 expression was reduced at 24 hours but returned to normal levels by 1 week. Endothelial cell density was not altered at 24 hours or 1 week. By 4 weeks, only CpG-ODN eyes showed relatively reduced ECD, as well as large numbers of CD45+ cells in the stroma. Changes to ECD correlated with CCT (r = -0.53, P < 0.01). Compared with naïve controls, more saline- and CpG-ODN-treated eyes exhibited polymegethism.
  
  
  
  This study provides novel insights into the interplay between endothelial cell integrity, corneal edema, and chronic stromal leukocyte activation during sterile corneal inflammation in mice.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Downie
authors.forename: Janet
authors.initials: J
authors.lastname: Choi
authors.forename: Jeremiah K H
authors.initials: JK
authors.lastname: Lim
authors.forename: Holly R
authors.initials: HR
authors.lastname: Chinnery
mesh_terms: D000818:Animals; D002452:Cell Count; D015715:Corneal Edema / Q000378:metabolism* / Q000473:pathology*; D065306:Corneal Injuries / Q000150:complications; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000473:pathology*; D004728:Endothelium, Corneal / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D019108:Tight Junctions / Q000378:metabolism*; D041623:Tomography, Optical Coherence; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
chemical_list: D062826:Zonula Occludens-1 Protein