CONICET | Buscador de Institutos y Recursos Humanos

P260.-Retinal effects of optic nerve inflammationFlorencia Altschuler, María F. González Fleitas, Mónica S. Chianelli, Pablo H. Sande, Damián Dorfman, Ruth E. Rosenstein, Marcos L. ArandaLaboratorio de Neuroquímica Retiniana y Oftalmología Experimental, Departamento de Bioquímica Humana,Facultad de Medicina, CEFyBO, UBA/CONICETPresenting author: Florencia Altschuler, florenciaaltschuler@gmail.com_________________________________________________________________________________________Optic neuritis (ON) is a condition involving primary inflammation, demyelination, and axonal injuryin the optic nerve which may provoke blindness. A subset of RGCs expressing the photopigmentmelanopsin (mRGCs) regulates non-image-forming visual functions such as the pupillary lightreflex (PLR), and circadian rhythms. We developed an experimental model of primary ON in ratsthrough a microinjection of bacterial lipopolysaccharide (LPS) into the optic nerve. The aim of thepresent work was to analyze the consequences of ON at retinal level. LPS or vehicle were injected into the optic nerve from adult male Wistar rats. At 4 days post-LPS, an increase in retinal Iba-1(+) area (a microglia/macrophage marker) that persisted until 21 days post-injection was observed, while GFAP-immunoreactivity increased at 21 days post-LPS. Moreover, at 21 days post-injection, LPS induced a significant loss of RGC number (by Brn3a immunoreactivity), whereas no changes in mRGCs number were observed. Experimental ON induced a decrease in the anterograde transport to the superior colliculus and suprachiasmatic nucleus (by CTB labeling) and a decrease in white and blue light-evoked PLR. These results suggest that experimental ON affects the retina at even early stages, and without changing mRGC number, it altered the non-image-forming visual system, supporting that alterations of circadian physiology could be a risk tothe qualityof life of patients with ON