Transfer of the Experimental Autoimmune Glaucoma Model from Rats to Mice—New Options to Study Glaucoma Disease

Abstract

Studies have suggested an involvement of the immune system in glaucoma. Hence, a rat experimental autoimmune glaucoma model (EAG) was developed to investigate the role of the immune response. Here, we transferred this model into mice. Either 0.8 mg/mL of the optic nerve antigen homogenate (ONA; ONA 0.8) or 1.0 mg/mL ONA (ONA 1.0) were injected in 129/Sv mice. Controls received sodium chloride. Before and 6 weeks after immunization, the intraocular pressure (IOP) was measured. At 6 weeks, retinal neurons, glia cells, and synapses were analyzed via immunohistology and quantitative real-time PCR (RT-qPCR). Additionally, optic nerves were examined. The IOP stayed in the normal physiological range throughout the study (p > 0.05). A significant reduction of retinal ganglion cells (RGCs) was noted in both immunized groups (p < 0.001). Remodeling of glutamatergic and GABAergic synapses was seen in ONA 1.0 retinas. Furthermore, both ONA groups revealed optic nerve degeneration and macrogliosis (all: p < 0.001). An increase of activated microglia was noted in ONA retinas and optic nerves (p < 0.05). Both ONA concentrations led to RGC loss and optic nerve degeneration. Therefore, the EAG model was successfully transferred from rats to mice. In further studies, transgenic knockout mice can be used to investigate the pathomechanisms of glaucoma more precisely.

Loss of the Extracellular Matrix Molecule Tenascin-C Leads to Absence of Reactive Gliosis and Promotes Anti-inflammatory Cytokine Expression in an Autoimmune Glaucoma Mouse Model

“…In a previous study, we already successfully transferred the EAG glaucoma model from rats to mice ( 49 ). Here, glaucomatous neurodegeneration was observed 6 weeks post ONA-immunization.…”

“…WT (WT ONA) and KO (KO ONA) mice were immunized intraperitoneally with ONA (1 mg/ml) mixed with incomplete Freund's adjuvants (FA; 50 μl) and 1 μg pertussis toxin (PTx; both Sigma Aldrich, St. Louis, MO, USA) as described ( 49 ). To generate the ONA homogenate, fresh bovine eyes were obtained from a local slaughterhouse (Schlachthaus Wuppertal, Germany).…”

Synapse and Receptor Alterations in Two Different S100B-Induced Glaucoma-Like Models

“…In EAG mice that received a systemic immunization with optic nerve antigen homogenate (ONA), a significantly lower inhibitory post-synapses signal was visualized by anti-gephyrin in a later stage of degeneration, after six weeks. Gephyrin is encoded by the GPHN gene, and a significant downregulation of the Gphn mRNA was also found [ 59 ]. In our study, neither the systemically immunized animals nor the intraocular-injected ones showed any differences regarding the synapses labeled by gephyrin after 14 days.…”

“…In a normal-tension glaucoma animal model, RGC death and optic nerve degeneration was observed in mice that were lacking the glutamate transporters GLAST or EAAC1, suggesting that glutamate transporters are necessary to prevent excitotoxicity [ 69 ]. Since VGluT1 is encoded by the Slc17a7 gene, a significantly lower level of its mRNA expression was found in ONA-immunized EAG mice after six weeks [ 59 ]. In the current study, we noted a tendency towards a higher VGluT1 signal in the systemically immunized S100B animals and a significant downregulation in rats receiving S100B intraocularly after 14 days.…”

Loss of the extracellular matrix molecule tenascin-C leads to absence of reactive gliosis and promotes anti-inflammatory cytokine expression in an autoimmune glaucoma mouse model

“…Tnc is also a key regulator of the 51 immune system and plays an important role during neuroinflammation and glial response 52 (Jakovcevski et characterized by an enhanced proliferation, migration, phagocytosis, and increased expression 58 levels of neuroinflammatory molecules (Langmann, 2007;Wolf et al, 2017). The neurotoxic M1-59 subtype has an amoeboid morphology and releases pro-inflammatory signaling molecules, like 60 tumor necrosis factor-alpha (TNF-α) and inducible nitric oxide synthase (iNOS) ( Louis, MO, USA) according to the previously described pilot study (Reinehr et al, 2019). FA 84 acted as an immunostimulatory and PTx was given to ensure the permeability of the blood retina 85 barrier.…”