Abstract

Glaucoma is a leading cause of irreversible blindness, characterized by progressive loss of retinal ganglion cells (RGCs), with glutamate excitotoxicity being a key contributor to RGC damage. Eugenol, a natural phenolic compound, has been shown to exhibit neuroprotective properties. However, protective effect of eugenol on glaucoma has not been explored. This study aimed to evaluate neuroprotective effects of eugenol in models of glutamate excitotoxicity and to explore the underlying mechanisms. The glutamate-induced R28 cell excitotoxicity model and N-methyl-D-aspartate (NMDA)-induced mouse glaucoma model were established. Cell Counting Kit-8 (CCK-8), iron ion probes, lipid peroxidation detection and other techniques were employed to elucidate whether eugenol could alleviate glutamate-induced ferroptosis. Subsequently, in vivo validation was performed using C57BL/6J mice. Eugenol significantly attenuated glutamate-induced R28 cell death and RGC damage. Eugenol restored Mitofusin 2 (Mfn2) levels reduced by glutamate excitotoxicity, thereby reducing abnormal lipid droplet (LD) accumulation and alleviating mitochondrial dysfunction. Furthermore, it upregulated solute carrier family 7 member 11 (SLC7A11), increased cellular glutathione (GSH) levels, and activated glutathione peroxidase 4 (GPX4) in an Mfn2-dependent manner, ultimately inhibiting ferroptosis. Eugenol exerts neuroprotective effects in glaucoma excitotoxicity models by suppressing ferroptosis through Mfn2-mediated regulation of mitochondrial-LD homeostasis and the SLC7A11/GSH/GPX4 antioxidant pathway.