Victor Paleo-García

Mouse models are essential for glaucoma research; however, strain-dependent biological differences may complicate the interpretation and translational value of experimental findings. Because baseline retinal immune tone can shape the response to ocular hypertension (OHT), defining constitutive inflammatory profiles across commonly used mouse strains is critical. Basal intraocular pressure (IOP), retinal interleukin (IL)-1β, interferon gamma (IFN-γ), IL-6, IL-4, IL-10, and vascular endothelial growth factor (VEGF) levels by Luminex xMAP, and the cellular localization of inflammatory mediators by immunofluorescence using Iba-1, GFAP, Brn3a, NF-200, and VEGFR1 were compared between male albino Swiss CD1 and pigmented C57BL/6J mice. Basal IOP did not differ between strains, whereas the basal retinal immune environment did. CD1 mice showed higher IL-1β and IL-4 levels and detectable IFN-γ, whereas C57BL/6J mice showed higher IL-6, IL-10, and VEGF levels. Immunofluorescence revealed strain-specific localization: in CD1 retinas, IL-1β was detected in microglia and macroglia, IFN-γ in microglia, and IL-6 mainly in microglia; in C57BL/6J retinas, IL-1β and IL-6 were mainly associated with macroglia (Müller cells and astrocytes), and IL-4 with microglia. In both strains, IL-10 localized to NF-200-positive axons and VEGFR1 to glial fibrillary acidic protein (GFAP)-positive macroglia. Despite similar basal IOP, albino Swiss CD1 and pigmented C57BL/6J mice differ markedly in their basal retinal immune profiles. Albino mice show a more reactive baseline state, whereas pigmented mice display tighter immunoregulation and stronger immune-vascular support. Strain selection is therefore critical for experimental design, data interpretation, and translational relevance to ensure preclinical findings translate into human outcomes.

This study evaluated the early structural and functional effects of combined citicoline and coenzyme Q10 (CoQ10) (CitiQ10) treatment in a laser-induced ocular hypertension (OHT) model in Swiss albino mice, focusing on retinal inflammation and neuroprotection. Sixty male CD-1 mice were assigned to four groups: vehicle, CitiQ10, OHT, and OHT + CitiQ10. OHT was induced by laser photocoagulation of limbal and episcleral veins, and CitiQ10 was administered orally starting 15 days before induction. Intraocular pressure (IOP) was measured by rebound tonometry, retinal structure was assessed by spectral domain optical coherence tomography (SD-OCT), and function was evaluated using full-field electroretinography (ffERG). At 3 days post-induction, OHT eyes exhibited significant retinal nerve fiber layer (RNFL) thickening, increased vitreous particles, and early functional impairment, particularly reduced scotopic b-wave and oscillatory potentials. CitiQ10 treatment mitigated these changes, reducing vitreous particles, moderating RNFL alterations, and not exhibiting significant changes in ERG amplitudes. At 7 days post-induction, structural and functional deficits persisted but were less pronounced in treated eyes. These findings suggest that CitiQ10 treatment may attenuate early retinal damage in glaucoma, with OCT and ffERG serving as reliable monitoring tools, supporting the therapeutic potential of this approach in early stage disease.

Background/Objectives: The loss of retinal ganglion cells (RGCs) is a hallmark of glaucoma, a major cause of blindness. Glial cell activation due to increased intraocular pressure (IOP) significantly contributes to RGC death. Therefore, substances with anti-inflammatory properties could help prevent that process. This study investigated whether combining Citicoline and Coenzyme Q10 (CoQ10) can reduce glial activation in the retina and the rest of the visual pathway, potentially preventing neurodegeneration in a mouse model of unilateral laser-induced ocular hypertension (OHT). Methods: Four groups of mice were used: vehicle (n = 12), CitiQ10 (n = 12), OHT–vehicle (n = 18), and OHT–CitiQ10 (n = 18). The administration of Citicoline and CoQ10 was performed orally once a day, initiated 15 days prior to the laser treatment and maintained post-treatment until sacrifice (3 days for retina or 7 days for the rest of the visual pathway). The retina, dorsolateral geniculate nucleus, superior colliculus, and visual cortex (V1) were immunohistochemically stained and analyzed. Results: In the laser–CitiQ10 group, the Citicoline + CoQ10 compound revealed (1) an IOP decrease at 24 h and 3 days post-laser; and (2) reduced signs of macroglial (decreased GFAP area) and microglial (soma size, arbor area, microglia number, P2RY12 expression) activation in the retina and in the rest of the visual pathway (reduced activated microglial phenotypes and lower GFAP expression). Conclusions: This study shows that oral administration of Citicoline and CoQ10 can reduce glial activation caused by increased IOP in retina and visual pathway in a mouse model of OHT, potentially protecting RGCs from OHT-induced inflammation.

Glaucoma is a neurodegenerative disease characterized by the loss of retinal ganglion cells (RGCs), with intraocular pressure (IOP) being its primary risk factor. Despite controlling IOP, the neurodegenerative process often continues. Therefore, substances with neuroprotective, antioxidant, and anti-inflammatory properties could protect against RGC death. This study investigated the neuroprotective effects on RGCs and visual pathway neurons of a compound consisting of citicoline and coenzyme Q10 (CoQ10) in a mouse model of unilateral, laser-induced ocular hypertension (OHT). Four groups of mice were used: vehicle group (n = 6), citicoline + CoQ10 group (n = 6), laser–vehicle group (n = 6), and laser–citicoline + CoQ10 group (n = 6). The citicoline + CoQ10 was administered orally once a day starting 15 days before laser treatment, continuing until sacrifice (7 days post-laser). Retinas, the dorsolateral geniculate nucleus (dLGN), the superior colliculus (SC), and the visual cortex (V1) were analyzed. The citicoline + CoQ10 compound used in the laser–citicoline + CoQ10 group demonstrated (1) an ocular hypotensive effect only at 24 h post-laser; (2) prevention of Brn3a+ RGC death in OHT eyes; and (3) no changes in NeuN+ neurons in the dLGN. This study demonstrates that the oral administration of the citicoline + CoQ10 combination may exert a neuroprotective effect against RGC death in an established rodent model of OHT.

Sodium iodate (NaIO₃) has been shown to cause severe oxidative stress damage to retinal pigment epithelium cells. This results in the indirect death of photoreceptors, leading to a loss of visual capabilities. The aim of this work is the morphological and functional characterization of the retina and the visual pathway of an animal model of retinal neurodegeneration induced by oxidative stress. Following a single intraperitoneal dose of NaIO₃ (65 mg/kg) to C57BL/6J mice with a mutation in the Opn4 gene (Opn4^−/−), behavioral and electroretinographic tests were performed up to 42 days after administration, as well as retinal immunohistochemistry at day 57. A near total loss of the pupillary reflex was observed at 3 days, as well as an early deterioration of visual acuity. Behavioral tests showed a late loss of light sensitivity. Full-field electroretinogram recordings displayed a progressive and marked decrease in wave amplitude, disappearing completely at 14 days. A reduction in the amplitude of the visual evoked potentials was observed, but not their total disappearance. Immunohistochemistry showed structural alterations in the outer retinal layers. Our results show that NaIO₃ causes severe structural and functional damage to the retina. Therefore, the current model can be presented as a powerful tool for the study of new therapies for the prevention or treatment of retinal pathologies mediated by oxidative stress.