Effects of Brimonidine, Omidenepag Isopropyl, and Ripasudil Ophthalmic Solutions to Protect against H 2 O 2 -Induced Oxidative Stress in Human Trabecular Meshwork Cells

We investigated whether hydrogen peroxide (H2O2)-induced oxidative stress causes human trabecular meshwork (HTM) cell dysfunction observed in open angle glaucoma (OAG) in vitro, and the effects of topical glaucoma medications on oxidative stress in HTM cells.We used commercially available ophthalmic solutions of brimonidine, omidenepag isopropyl, and ripasudil in the study. HTM cells were exposed to H2O2 for 1 h, with or without glaucoma medications. We assessed cell viability and senescence via WST-1 and senescence-associated-β-galactosidase (SA-β-Gal) activity assays. After exposure to H2O2 and glaucoma medications, we evaluated changes in markers of fibrosis and stress by using real-time quantitative polymerase chain reaction (qPCR) to measure the mRNA levels of collagen type I alpha 1 chain (COL1A1), fibronectin, alpha-smooth muscle actin (α-SMA), matrix metalloproteinase-2 (MMP-2), endoplasmic reticulum stress markers of C/EBP homologous protein (CHOP), 78-kDa glucose-regulated protein (GRP78), and splicing X-box binding protein-1 (sXBP-1).HTM cell viability decreased and SA-β-Gal activity increased significantly after exposure to H2O2. Treatment with three ophthalmic solutions attenuated these changes. Real-time qPCR revealed that H2O2 upregulated the mRNA levels of COL1A1, fibronectin, α-SMA, CHOP, GRP78, and sXBP-1, whereas it downregulated MMP-2 mRNA expression significantly. Brimonidine suppressed the upregulation of stress markers CHOP and GRP78. Additionally, omidenepag isopropyl and ripasudil decreased the upregulation of COL1A1 and sXBP-1. Furthermore, ripasudil significantly suppressed fibrotic markers fibronectin and α-SMA, compared with the other two medications.In vitro, H2O2 treatment of HTM cells induced characteristic changes of OAG, such as fibrosis changes and the upregulation of stress markers. These glaucomatous changes were attenuated by additional treatments with brimonidine, omidenepag isopropyl, and ripasudil ophthalmic solutions.