Experimental studies of retinal glial cell proliferation on retinal surface

Our previous reports described the formation processes of epiretinal membranes composed of retinal glial cells in the experimental vitreous hemorrhage. This report presents the pathological changes of retinal glial cells, inner limiting membranes and vitreous body in the early stage of experimental vitreous hemorrhage. Using an operating microscope, 0.3 ml of autologous whole blood was injected through the pars plana into the vitreous cavity of albino rabbits. The eyes were enucleated at 3, 7, 10, 14 and 28 days after injection. Three days after injection, normal vitreous structure disappeared and vitreous fibers condensed. Seven days after injection, red blood cells were found on the retinal surface. The inner limiting membrane, composed of lamina rara and lamina densa, had a normal appearance. Where the red blood cell were present on the retinal surface, the lamina rara of the inner limiting membrane became thin. Fourteen days after injection, where glial cells showed upheaval, lamina rara disappeared and lamina densa became thin. Afterward, glial cells extruded their cytoplasmic processes onto the retinal surface. Twenty-eight days after injection, the inner limiting membranes were normal in appearance except for the area of glial cells penetrating the inner limiting membranes. The results suggested that, in vitreous hemorrhage, glial cell proliferation onto the retinal surface is an active reaction in order to engulf the debris of the red blood cells.