CHANGES IN RABBIT CORNEAL EPITHELIAL MEMBRANE-PERMEABILITY CAUSED BY LOCALLY APPLIED PSEUDOMONAS-AERUGINOSA CYTOTOXIN - A MICROFLUOROMETRICEXAMINATION IN-VIVO

The effects of a pore-forming protein from Pseudomonas aeruginosa on t he rabbit cornea were tested in vivo by measuring intraepithelial carb oxyfluorescein accumulation. Carboxyfluorescein diacetate and subseque ntly the P. aeruginosa cytotoxin were applied by means of contact lens es with a spherical cavity on the concave surface. This allowed the ap plication of defined concentrations of carboxyfluorescein diacetate an d cytotoxin on a defined area of the corneal epithelium. Starting at 0 .5 muM, cytotoxin increased the epithelial cell membrane permeability for the intracellular carboxyfluorescein within 1 min. At higher conce ntrations ce Is were shed from the epithelium. Corresponding morpholog ical changes of the cellular structure of the corneal epithelium were observed and documented by fluorescence photomicrography. The healing process of toxified corneal epithelium appeared to be complete within 3 days. The data presented here indicate the possible role of cytotoxi n-induced changes in epithelial permeability in P. aeruginosa infectio ns. In this context, the role of soft contact lenses as a possible cyt otoxin reservoir is discussed.