Abstract
Purpose: :
To analyze 1) permeability of retinal pigment epithelial cells (RPE) in response to Bacillus infection and 2) permeability of the blood ocular barrier (BOB) during experimental B. cereus endophthalmitis.
Methods: :
RPE were infected with toxigenic B. cereus and changes in BRB permeability were analyzed at various times postinfection using a dextran conjugate permeability assay. C57BL/6J mice were infected intravitreally with toxigenic B. cereus and changes in BRB permeability analyzed by quantifying albumin leakage into the retina and whole eye. BOB permeability of albumin and fibrin was evaluated by immunohistochemistry and trichrome staining, respectively.
Results: :
Bacillus infection of RPE resulted in a dose– and time–dependent increase in migration of FITC–dextran through the monolayers. Blood retinal barrier permeability was also demonstrated during experimental B. cereus endophthalmitis. At 8 hours postinfection, three times more dye was detected in the retina compared with uninfected controls. Albumin and fibrin leakage were detected in both the posterior and anterior chambers at 8 hours postinfection. Leakage appeared to originate first from the ciliary body and later from the blood retinal barrier.
Conclusions: :
Leakage of blood constituents into the retina, posterior, and anterior chamber occurred during experimental Bacillus endophthalmitis. We hypothesize that BOB permeability occurs in response to toxic effects of B. cereus on RPE. Future studies will focus on determining the mechanisms of BOB permeability and its effects on loss of retinal structure and function during Bacillus endophthalmitis.
Keywords: endophthalmitis • bacterial disease • retinal pigment epithelium