Effects of Ripasudil, a Rho-Kinase Inhibitor, on Scar Formation in a Mouse Model of Filtration Surgery

Purpose: Glaucoma is a leading cause of blindness worldwide. Characteristic changes occur in the optic nerve and visual field of patients with glaucoma; optic nerve damage can be mitigated by lowering intraocular pressure. Treatment modalities include drugs and lasers; filtration surgery is necessary for patients with insufficient intraocular pressure reduction. Scar formation often contributes to glaucoma filtration surgery failure by increasing fibroblast proliferation and activation. Here, we examined the effects of ripasudil, a Rho-associated protein kinase (ROCK) inhibitor, on postoperative scar formation in human Tenon's fibroblasts.

Materials and methods: Collagen gel contraction assays were used to compare contractility activity among ripasudil and other anti-glaucoma drugs. The effect of Ripasudil in combination with other anti-glaucoma drugs and Transforming Growth Factor-β (TGF-β), latanoprost and timolol-induce contractions were also tested in this study. Immunofluorescence and western blotting were used to study the expression of factors relating scarring formation.

Results: Ripasudil inhibited contraction in collagen gel assay and reduced α-smooth muscle actin (SMA) and vimentin (scar formation-related factors) expression, which was inversely promoted by latanoprost, timolol or TGF-β. Ripasudil also inhibited contraction on TGF-β, latanoprost and timolol-induced contraction. Furthermore, we investigated the effects of ripasudil on postoperative scarring in a mouse model; ripasudil suppressed postoperative scar formation by altering the expression of α-SMA and vimentin.

Conclusions: These results suggest that ripasudil, ROCK Inhibitor may inhibit excessive fibrosis after glaucoma filtering surgery vis inhibition the transdifferentiation of tenon fibroblast into myofibroblast and may have a potential effect as anti-scarring for glaucoma filtration surgery.

ROCK inhibitor; filtering surgery; glaucoma; scarring formation; wound healing.