The role of breakdown of the blood-retinal barrier in cell-injection models of proliferative vitreoretinopathy
H. A. Sen, T. J. Robertson, B. P. Conway and P. A. Campochiaro
Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville 22908.
Rabbits were given an intravitreous injection of 5.0 x 10(5) rabbit retinal
pigment epithelial (RPE) cells, human RPE cells, or human dermal
fibroblasts in one eye and an injection of vehicle alone in the other eye.
Some rabbits were treated with retinal cryopexy or intravenous sodium
iodate on the day before injection. Vitreous fluorophotometry (VFP) and
fundus examinations were performed before and at various times after cell
injections. Retinal detachments were graded by premortem ophthalmoscopic
examinations and postmortem gross pathologic examinations. Eyes injected
with cells had higher VFP readings than eyes injected with vehicle at all
time points. Eyes injected with fibroblasts or rabbit RPE had significantly
higher mean VFP values before the onset of retinal detachment than those
injected with human RPE cells. Within each group, high levels of
fluorescein leakage in the first week correlated well with severity of
subsequent traction retinal detachment and the fibroblast and rabbit RPE
groups had more severe detachments than the human RPE group. Treatment with
cryopexy or sodium iodate resulted in higher VFP readings, a higher
frequency of retinal detachments, and detachments that occurred earlier and
that were more severe. These data demonstrate that intravitreous cells
cause blood-retinal barrier breakdown in rabbits and that the amount and
duration of this breakdown are important variables in retinal detachment
formation.
