title: Cytoprotective effects of hyaluronic acid and Carbomer 934P in ocular surface epithelial cells.
abstract: OBJECTIVE
  To investigate in vitro the cell toxicity and antioxidant effects of two major tear substitutes, hyaluronic acid and a widely used carbomer, with and without preservative.
  
  
  METHODS
  Chang conjunctival cells were treated with different concentrations of unpreserved or preserved carbomer 934P (0.03% and 0.3%), unpreserved or preserved hyaluronic acid (0.018% and 0.18%), and benzalkonium chloride (BAC 0.0005% and 0.005%) for 15 minutes or for 15 minutes with 24 hours of cell recovery, according to previously validated methods. Microplate cold light cytofluorometry was performed to evaluate cell viability (neutral red test), chromatin condensation (Hoechst 33342 test), and reactive oxygen species (ROS) production (dichlorofluorescein diacetate and hydroethidine tests). Confocal microscopy was used to explore morphologic changes.
  
  
  RESULTS
  No alterations were found with unpreserved and preserved hyaluronic acid at all concentrations and times tested. A decrease in cell viability with chromatin condensation appeared with 0.3% preserved carbomer 934P at the two times tested. This cytotoxicity, however, was significantly less than that observed with BAC alone, although the same concentrations of preservative were used. Unpreserved carbomer 934P induced no modification of cell viability after 15 minutes but a significant decrease in chromatin condensation, reversible after 24 hours of cell recovery, when a delayed decrease in cell viability was observed. Production of reactive oxygen species (ROS) decreased with the four formulations of tear substitutes tested at their usual concentrations, whereas a significant production of ROS occurred with BAC.
  
  
  CONCLUSIONS
  These two ophthalmic hydrogels have no cytotoxicity but possess antioxidant properties and tend to reduce the toxic effects of preservatives. These results may allow use of hydrogels, not only in dry eye but also in ocular surface disorders involving oxidative stress and in ophthalmic drug therapy to improve ocular tolerance.
authors.affiliation: Cellular Pharmacotoxicology Unit, Toxicology Laboratory, Quinze-Vingts, National Hospital Center for Ophthalmology, Ambroise Paré AP-HP, University of Paris-V, Paris, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Debbasch
authors.forename: Stéphanie Bruneau
authors.initials: SB
authors.lastname: De La Salle
authors.forename: Françoise
authors.initials: F
authors.lastname: Brignole
authors.forename: Patrice
authors.initials: P
authors.lastname: Rat
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Warnet
authors.forename: Christophe
authors.initials: C
authors.lastname: Baudouin
mesh_terms: D000180:Acrylic Resins / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D001548:Benzalkonium Compounds / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects*; D019610:Cytoprotection / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology*; D018613:Microscopy, Confocal; D009883:Ophthalmic Solutions / Q000494:pharmacology; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology; D017382:Reactive Oxygen Species
chemical_list: D000180:Acrylic Resins; D000975:Antioxidants; D001548:Benzalkonium Compounds; D002843:Chromatin; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical; D017382:Reactive Oxygen Species; C006903:carbopol 940; D006820:Hyaluronic Acid