title: Comparison of the ocular surface changes following the use of two different prostaglandin F2α analogues containing benzalkonium chloride or polyquad in rabbit eyes.
abstract: OBJECTIVE
  The aim of this study is to compare the effect of prostaglandin analogues preserved with either 0.015% or 0.001% benzalkoium chloride (BAK); or 0.001% polyquad (PQ) on the ocular surface of rabbit eyes.
  
  
  METHODS
  Forty white rabbits were randomized to receive four-times daily instillation of either 0.0015% tafluprost (TF) preserved with 0.001% BAK (TF-BAK); 0.004% travoprost (TR) with 0.015% BAK (TR-BAK) or 0.001% PQ (TR-PQ); or preservative-free artificial tears in one eye for a 4-week period. Tear samples collected from the 40 rabbits were analyzed by enzyme-linked immunosorbent assays (ELISA) to identify the presence of inflammatory cytokines: interleukin (IL)-1β and IL-6 on day 14. Subsequently, harvested cornea and bulbar conjunctiva were evaluated using light and transmission electron microscopy (TEM).
  
  
  RESULTS
  IL-6 was significantly increased in TF-BAK and TR-BAK groups compared to controls and TR-PQ group (p = 0.005); however, IL-1β level was not significantly different among four groups (p = 0.360). Rabbits treated with TR-BAK showed decreased goblet cell density of bulbar conjunctiva and increased pyknotic change and vacuolization of corneal epithelial cells on light microscopy; similar change occurred but was less severe in TF-BAK group. The TR-PQ group showed similar results as the controls. The destruction of the microvillar architecture of bulbar conjunctiva and cornea was most prominent in the TR-BAK group.
  
  
  CONCLUSIONS
  Preservatives included in the anti-glaucoma eye-drops showed different ocular surface changes according to the concentration and type in the rabbits. Prostaglandin analogues preserved with higher level of BAK may cause more harmful effects on the ocular surface than PQ-preserved medications.
authors.affiliation: Department of Ophthalmology, Eulji Medical Center, Eulji University School of Medicine , Seoul , Korea .
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Lee
authors.forename: Roo Min
authors.initials: RM
authors.lastname: Jun
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Cho
authors.forename: Kyu-Ryong
authors.initials: KR
authors.lastname: Choi
mesh_terms: D000818:Animals; D001548:Benzalkonium Compounds / Q000032:analysis*; D003228:Conjunctiva / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D016207:Cytokines / Q000378:metabolism; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D046529:Microscopy, Electron, Transmission; D011108:Polymers / Q000032:analysis*; D011460:Prostaglandins F / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D013666:Tears / Q000378:metabolism; D000069557:Travoprost / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001548:Benzalkonium Compounds; D016207:Cytokines; D018836:Inflammation Mediators; D011108:Polymers; D011460:Prostaglandins F; C485333:tafluprost; C058655:polyquaternium 1; D000069557:Travoprost
keywords: Benzalkonium chloride; ocular surface; polyquad