Abstract
Abstract: :
Purpose: We previously demonstrated the early presence of phagocytic/microglial cells with nitric oxide synthase in ocular tissues in experimental glaucoma in rats. This study examines the roles of these cells by studying their cytokine profiles. Methods: Ueda’s procedure of intracameral India ink injection followed by laser trabecular photocoagulation at 7 days was used to produce a short-term mild intraocular pressure (IOP) elevation in rats. Animals were euthanized at various times after laser. Single and double antigen immunohistochemistry was performed on retinal sections with optic nerve head attached. Results: IL-1α-, IL-6- and IFNγ-positive cells showed different spatial and temporal patterns. Scattered IFNγ-positive cells were noted early and persistently in the optic nerve but not in the retina. IL-6-positive cells also appeared early in isolated cells in the optic nerve but not in the retina. However, from 5 to 14 days, IL-6-positive cells were seen in both the retina and the optic nerve. Unexpectedly, no IL-1α-positive cells were detected in the retina and the optic nerve throughout the observation period. Double labeling of IL-6 and IFNγ showed isolated IL-6- or IFNγ-positive cells in the optic nerve but there was no colocalization of the two. In contrast, some cells did show colocalization in the retina. IL-6 always colocalized with ED-1. Conclusion: After IOP elevation, at different times and locations in ocular tissue, phagocytic cells may play different roles based on their cytokine profiles and actions.
Keywords: 380 cytokines/chemokines • 444 intraocular pressure