C. Baudouin et al., INFLAMMATION MEASUREMENT AND IMMUNOCHARACTERIZATION OF CELL-PROLIFERATION IN AN EXPERIMENTAL-MODEL OF PROLIFERATIVE VITREORETINOPATHY, Ophthalmic research, 30(6), 1998, pp. 340-350
An experimental model of proliferative vitreoretinopathy was developed
in the rabbit eye by injecting a solution of human platelet-rich plas
ma. In this model we evaluated the progression with time of intraocula
r inflammation and the rate and origin of cell proliferation. A steril
e solution adjusted to 10(7) platelets was injected into the right eye
of a total of 46 pigmented and 14 albino rabbits. Animals were sequen
tially sacrificed at days 7, 14, 21 and 1 month after injection, Clini
cal evaluation of vitreoretinal proliferation, using a classification
in six grades, and of anterior segment inflammation assessed by a Lase
r Flare Meter, were done for 1 month after injection, before histopath
ological analysis. Eighty percent of eyes developed tractional retinal
detachment in 1 month. Histopathology showed intense cell migration a
nd proliferation in the area of the ciliary body, as early as the seve
nth day, then further increasing rapidly. Infiltrates were composed of
cytokeratin- and vimentin-expressing cells. Abnormal expression of vi
mentin was also found in ciliary and retinal epithelia and in Muller c
ells. Inflammation measured by the Laser Flare Meter was maximal at da
y 11 and then reached a plateau at significantly higher levels than co
ntrols. Albino rabbits showed significantly lower grades of proliferat
ion, as compared to pigmented rabbits. This study thus clarified some
characteristics of experimental vitreoretinal proliferations that prov
ed similar to those in human diseases, such as the involvement of cili
ary body and retinal pigment epithelium, the existence of inflammatory
reactions preceding cell proliferation and strong changes in intermed
iate filaments, This may provide a simple and valuable model for antip
roliferative assays and shed some light on the pathogenesis of intraoc
ular proliferative disorders.