Abstract
Purpose :
Mice null for the transcription factor Spdef (sam pointed domain ETS factor), a member of the ETS transcription factor family, lack goblet cells. A recent paper demonstrated lack of conjunctival goblet cells in these mice thus providing a model to test goblet cell function at the ocular surface (Marko et al, American Journal of Pathology 2013). The purpose of this study was to determine the role of goblet cells or their secretions in protecting the ocular surface from infection by Pseudomonas aeruginosa strain 6294, a strain known to infect mice.
Methods :
Mice null for Spdef, as well as wild type (WT) controls were used. Five µl of Pseudomonas aeruginosa strain 6294 at 1x107 CFU/ml diluted in normal saline were applied to both eyes of 4 mice from each group twice daily for three days. Eyes were examined grossly and by slit lamp with fluorescein staining each day and at 24 hours after the last bacterial application. Animals were sacrificed after the last observation and eyes were dissected and embedded for histology and immunofluorescence microscopy. Additional histological sections from eyes from Spdef-/- and WT mice were assessed for debris accumulation in the conjunctival cul-de-sac.
Results :
None of the animals showed ocular infection either grossly, by fluorescein staining or by histology. There was however debris noted in the conjunctival cul-de-sac of the Spdef -/- mice. This led us to examine histology sections of additional Spdef null mice not exposed to bacteria. Twelve out of 19 Spdef -/- mice showed debris accumulation in conjunctival cul-de-sacs, compared to no debris in 23 WT animals.
Conclusions :
These data suggest that neither goblet cells nor their secretions are necessary for protection from bacterial invasion by Pseudomonas aeruginosa. The data do indicate, however, that goblet cells and their secretions are involved in debris clearance from the ocular surface.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.