Spermidine mitigates blue-light-induced corneal injury by alleviating oxidative stress and restoring autophagy impairment

This study investigated the protective efficacy of spermidine on corneal epithelium exposed to photodamage from artificial blue light (BL). After six weeks of BL exposure, the rabbit cornea exhibited epithelial injury and delayed wound healing accompanied by downregulation of spermidine, as identified through metabolomic analysis. Pathways related to autophagy and the antioxidant response were implicated in this process. In vitro, spermidine mitigated BL-induced reductions in viability and proliferation of human corneal epithelial cells, decreased cell death, and enhanced colony formation. Spermidine also partially reversed BL-induced mitochondrial dysfunction, oxidative stress and autophagy impairment. Furthermore, topical administration of spermidine eye drops reduced epithelial injury in the rabbit cornea under BL exposure, demonstrating benefits in promoting cell proliferation, accelerating wound healing, and maintaining antioxidant capacity and autophagy.