title: Restoring conjunctival tolerance by topical nuclear factor-κB inhibitors reduces preservative-facilitated allergic conjunctivitis in mice.
abstract: OBJECTIVE
  To evaluate the role of nuclear factor-κB (NF-κB) activation in eye drop preservative toxicity and the effect of topical NF-κB inhibitors on preservative-facilitated allergic conjunctivitis.
  
  
  METHODS
  Balb/c mice were instilled ovalbumin (OVA) combined with benzalkonium chloride (BAK) and/or NF-κB inhibitors in both eyes. After immunization, T-cell responses and antigen-induced ocular inflammation were evaluated. Nuclear factor-κB activation and associated inflammatory changes also were assessed in murine eyes and in an epithelial cell line after BAK exposure.
  
  
  RESULTS
  Benzalkonium chloride promoted allergic inflammation and leukocyte infiltration of the conjunctiva. Topical NF-κB inhibitors blocked the disruptive effect of BAK on conjunctival immunological tolerance and ameliorated subsequent ocular allergic reactions. In line with these findings, BAK induced NF-κB activation and the secretion of IL-6 and granulocyte-monocyte colony-stimulating factor in an epithelial cell line and in the conjunctiva of instilled mice. In addition, BAK favored major histocompatibility complex (MHC) II expression in cultured epithelial cells in an NF-κB-dependent fashion after interaction with T cells.
  
  
  CONCLUSIONS
  Benzalkonium chloride triggers conjunctival epithelial NF-κB activation, which seems to mediate some of its immune side effects, such as proinflammatory cytokine release and increased MHC II expression. Breakdown of conjunctival tolerance by BAK favors allergic inflammation, and this effect can be prevented in mice by topical NF-κB inhibitors. These results suggest a new pharmacological target for preservative toxicity and highlight the importance of conjunctival tolerance in ocular surface homeostasis.
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Guzmán
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: Florencia
authors.initials: F
authors.lastname: Sabbione
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: María Laura
authors.initials: ML
authors.lastname: Gabelloni
authors.affiliation: Institute of Oncologic Research, National Academy of Medicine, Buenos Aires, Argentina.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vanzulli
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: Analía Silvina
authors.initials: AS
authors.lastname: Trevani
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: Mirta Nilda
authors.initials: MN
authors.lastname: Giordano
authors.affiliation: Institute of Experimental Medicine, National Academy of Medicine/CONICET, Buenos Aires, Argentina.
authors.forename: Jeremías Gastón
authors.initials: JG
authors.lastname: Galletti
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001548:Benzalkonium Compounds / Q000633:toxicity*; D015153:Blotting, Western; D002460:Cell Line; D018920:Coculture Techniques; D003228:Conjunctiva / Q000166:cytology / Q000276:immunology*; D003233:Conjunctivitis, Allergic / Q000139:chemically induced / Q000276:immunology / Q000517:prevention & control*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006968:Hypersensitivity, Delayed / Q000276:immunology; D020672:I-kappa B Proteins / Q000494:pharmacology*; D007108:Immune Tolerance / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010047:Ovalbumin / Q000633:toxicity; D011310:Preservatives, Pharmaceutical / Q000633:toxicity*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D001548:Benzalkonium Compounds; D016207:Cytokines; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D011310:Preservatives, Pharmaceutical; D000072000:NF-KappaB Inhibitor alpha; D010047:Ovalbumin
keywords: NF-κB; allergic conjunctivitis; benzalkonium chloride; conjunctival epithelium; conjunctival tolerance; preservative