EIU in the rat promotes the potential of syngeneic retinal cells injected.into the vitreous cavity to induce PVR

PURPOSE. To determine whether syngeneic retinal cells injected in the vitre ous cavity of the rat are able to initiate a proliferative process and whet her the ocular inflammation induced in rats by lipopolysaccharide (LPS) pro motes this proliferative vitreoretinopathy (PVR). METHODS. Primary cultured differentiated retinal Muller glial (RMG) and ret inal pigmented epithelial (RPE) cells isolated from 8 to 12 postnatal Lewis rats were injected into the vitreous cavity of 8- to 10-week-old Lewis rat s (10(5) cells/eye in 2 mul sterile saline), with or without the systemic i njection of 150 mug LPS to cause endotoxin-induced uveitis (EIU). Control g roups received an intravitreal injection of 2 mul saline. At 5, 15, and 28 days after cell injections, PVR was clinically quantified, and immunohistoc hemistry for OX42, ED1, vimentin (VIM), glial fibrillary acidic protein (GF AP)I and cytokeratin was performed. RESULTS. The injection of RMG cells, alone or in combination with RPE cells , induced the preretinal proliferation of a GFAP-positive tissue, that was enhanced by the systemic injection of LPS. Indeed, when EIU was induced at the time of RMG cell injection into the vitreous cavity, the proliferation led to retinal folds and localized tractional detachments. In contrast, PVR enhanced the infiltration of inflammatory cells in the anterior segment of the eye. CONCLUSIONS. In the rat, syngeneic retinal cells of glial origin induce PVR that is enhanced by the coinduction of EIU. In return, vitreoretinal glial proliferation enhanced the intensity and duration of EIU.