IMMUNOHISTOCHEMICAL PROOF OF ORIGIN OF MACROPHAGES IN LASER PHOTOCOAGULATION LESION IN THE RETINA

The origin of the macrophages which appear in the subretinal space aft er laser photocoagulation on the rat retina was investigated using imm unohistochemistry. The majority of macrophages located in laser lesion s were found to be positive to staining for the specific rat monocyte/ macrophage marker (ED1). The number of macrophages and activated macro phages were abundant after intense laser photocoagulation in which cho roidal neovascularization was induced. After the retinal pigment epith elium (RPE) was damaged by intravenous administration of sodium iodate , the number of migrating macrophages in the subretinal space of laser ed areas significantly decreased to a level comparable to the level fo und in control animals. These results suggested that the macrophages w ere derived mainly from monocytes in the blood, not from RPE cells, an d that they may play a role in the development of the choroidal neovas cularization.