Metformin alleviates dry eye-associated corneal epithelial senescence and oxidative stress via AMPK activation.

Abstract

BACKGROUND: Stress-induced premature senescence (SIPS) and oxidative stress play critical roles in the pathogenesis of Dry Eye Disease (DED), a chronic condition characterized by tear film instability and ocular surface damage. While metformin exhibits known anti-aging and antioxidative properties, its specific therapeutic efficacy and underlying mechanisms in non-diabetic DED remain largely undefined. METHODS: An in vitro hyperosmotic stress model using human corneal epithelial cells (HCECs) and an in vivo benzalkonium chloride (BAC)-induced DED mouse model were established. Cellular viability, senescence (SA-β-gal, p16, p21, p53), oxidative stress (ROS), and barrier integrity (ZO-1) were evaluated using CCK-8, Western blot, RT-qPCR, and immunofluorescence. The mechanistic role of the AMPK pathway was analyzed using transcriptomic data (GSE252984) and validated using the AMPK inhibitor Compound C and the NRF2 inhibitor ML385. RESULTS: Bioinformatics analysis identified the AMPK signaling cascade as a profoundly dysregulated pathway in DED-associated senescence. In vitro, metformin pretreatment significantly attenuated hyperosmolarity-induced cell death, ROS accumulation, and the expression of senescence and inflammatory markers. Mechanistically, metformin activated the AMPK/SIRT1 axis to suppress senescence and promoted NRF2 nuclear translocation to restore redox balance; these protective effects were reversed upon AMPK or NRF2 inhibition. In vivo, systemic administration of metformin preserved corneal epithelial thickness, decreased apoptosis, and reduced senescence markers in DED mice. Notably, co-administration of Compound C neutralized these therapeutic benefits. CONCLUSION: Metformin effectively alleviates corneal epithelial injury and SIPS in non-diabetic DED by modulating the AMPK/SIRT1 and NRF2 signaling pathways. These findings highlight metformin as a promising repurposable therapeutic agent for breaking the pathological cycle of ocular surface damage.

Key Findings

• Metformin pretreatment significantly attenuated hyperosmolarity-induced cell death, ROS accumulation, and the expression of senescence and inflammatory markers in human corneal epithelial cells.
• Metformin activated the AMPK/SIRT1 axis and promoted NRF2 nuclear translocation to restore redox balance, with protective effects reversed by AMPK or NRF2 inhibition.
• Systemic administration of metformin in a dry eye disease mouse model preserved corneal epithelial thickness, decreased apoptosis, and reduced senescence markers, effects neutralized by AMPK inhibition.

Clinical Significance

Citation

Yang Chunhui, Shu Xingyi, Wang Qiuyuet al.. Metformin alleviates dry eye-associated corneal epithelial senescence and oxidative stress via AMPK activation. Experimental eye research. 2026-Nov-06.