Abstract
Abstract: :
Purpose: We showed that the injection of hyaluronic acid (HA) in rat anterior chamber significantly increases intraocular pressure (IOP). The aim of the present work was to study the effect of the chronic intracameral administration of HA with respect to electroretinographic (ERG) changes and retinal morphology. Methods: HA was injected weekly (during 10 weeks) in the rat anterior chamber, whereas the contralateral eye was injected with saline solution. Electroretinographic activity was assessed in both eyes of each animal under scotopic conditions with a gold electrode after 6 or 10 weeks of treatment. Retinal morphology was examined by optical microscopy and immunohistochemistry. Results: After 6 weeks of HA administration a reduction of 16% in the amplitude of both a and b wave of the scotopic ERG was observed. These parameters were significantly reduced after 10 weeks of treatment with HA (reduction of 22% and of 33% for a and b wave, respectively). In the animals that received HA during 10 weeks, a loss of ganglion cells as well as a reduced number of Muller cells was observed, as compared to eyes injected with saline solution. In addition, at the lamina cribosa level, an axonal rarefaction was observed in the eyes injected with HA. Conclusion: Present results indicate that the chronic administration of HA induced a significant decrease in the electroretinographic activity and several morphological changes in the retina and optic nerve that seem consistent with some features of primary open-angle glaucoma. Therefore, this could be an experimental model to study the cellular mechanisms by which elevated IOP damages the optic nerve and the retina.
Keywords: 316 animal model • 554 retina • 444 intraocular pressure