title: A comparison of basal and eye-flush tears for the analysis of cat tear proteins.
abstract: OBJECTIVE
  To identify a rapid and effective tear collection method providing sufficient tear volume and total protein content (TPC) for analysis of individual proteins in cats.
  
  
  METHODS
  Domestic adult short-haired cats (12-37 months; 2.7-6.6 kg) were used in the study. Basal tears without stimulation and eye-flush tears after instillation of saline (10 μl) were collected using microcapillary tubes from animal eyes either unwounded control or wounded with 9-mm central epithelial debridement giving four groups with n = 3. Tear comparisons were based on total time and rate for tear collection, TPC using micro bicinchoninic acid (BCA), tear immunoglobulin A (IgA), total matrix-metalloproteinase (MMP)-9 concentration using sandwich enzyme-linked immunosorbent assay (ELISA) and MMP-9 activity.
  
  
  RESULTS
  Eye-flush tears were collected significantly faster than basal tears in wounded eyes with higher rates for tear collection in unwounded control and wounded eyes. TPC was significantly lower in eye-flush tears compared to basal tears. The relative proportion of tear IgA normalized to TPC (% IgA of TPC) was not significantly different between basal and eye-flush tears. In unwounded control eyes, MMP-9 was slightly higher in eye-flush than in basal tears; activity of MMP-9 in both tear types was similar. In wounded eyes, eye-flush tears showed highest MMP-9 levels and activity on Day 1, which subsequently decreased to Day 7. MMP-9 activity in basal tears from wounded eyes did not display changes in expression.
  
  
  CONCLUSIONS
  Eye-flush tears can be collected rapidly providing sufficient tear volume and TPC. This study also indicates that eye-flush tears may be more suitable than basal tears for the analysis of MMPs following corneal wounding.
authors.affiliation: Vision CRC, Sydney, NSW, Australia. andrea_petznick@yahoo.com.au
authors.forename: Andrea
authors.initials: A
authors.lastname: Petznick
authors.forename: Margaret D M
authors.initials: MD
authors.lastname: Evans
authors.forename: Michele C
authors.initials: MC
authors.lastname: Madigan
authors.forename: Maria
authors.initials: M
authors.lastname: Markoulli
authors.forename: Qian
authors.initials: Q
authors.lastname: Garrett
authors.forename: Deborah F
authors.initials: DF
authors.lastname: Sweeney
mesh_terms: D000818:Animals; D002415:Cats; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000032:analysis*; D005260:Female; D007070:Immunoglobulin A / Q000032:analysis; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D013048:Specimen Handling; D013666:Tears / Q000737:chemistry*
chemical_list: D005136:Eye Proteins; D007070:Immunoglobulin A; C042434:tear proteins; D020780:Matrix Metalloproteinase 9