Topical Rho-Associated Protein Kinase Inhibitor HA1077 Reduces Rabbit Corneal Fibrosis and Neovascularization In Vivo.

PURPOSE: Rho-associated kinase (ROCK) regulates fibrosis and angiogenesis. This study evaluated the effects of the topical ROCK inhibitor HA1077 (fasudil) to attenuate corneal fibrosis and corneal neovascularization (CNV) in vivo.

METHODS

Primary human corneal stromal fibroblasts (hCSF) and New Zealand White rabbits (n = 12) were used. Corneal fibrosis and CNV in vivo were provoked by alkali injury. Immediately post-injury, eyes received topical balanced salt solution (BSS) or HA1077 (3 nM twice/day for 3 days). Clinical slit-lamp biomicroscopy and stereomicroscopy gauged corneal haze/fibrosis (Fante's score) and CNV (morphometric score) in live rabbits. Post-euthanasia, H&E, immunofluorescence, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays analyzed α-smooth muscle actin (α-SMA), filamentous actin (F-actin), endoglin, CD11b, and apoptotic cells.

RESULTS

HA1077 treatment to hCSF did not alter viability, morphology, and proliferation ability at 3 nM or lower doses. Topical HA1077 (3 nM) treatment significantly reduced corneal haze/fibrosis (P < 0.0001) and CNV (P < 0.0001) in vivo at days 7 and 14 compared with the corresponding controls. Histological H&E analysis revealed retrieval of overall corneal health with a remarkable decrease in fibrotic (myofibroblasts), angiogenic (neovessels), and immune cell infiltration in rabbit corneas treated with HA1077 than the control corneas. HA1077 therapy significantly reduced α-SMA+, F-actin+, and endoglin+ cells, markers of fibrosis and CNV. Intraocular pressure (IOP) remained within the normal physiological range of eyes with HA1077. TUNEL assay revealed the tolerability of the examined HA1077 regimen in vivo.

CONCLUSIONS

The tested HA1077 dosage regimen is effective and tolerable to rabbit eyes in abrogating corneal fibrosis and CNV triggered by alkali injury in vivo without major adverse effects. ROCK inhibition represents a promising therapeutic strategy for vascularized and fibrotic corneal wounds but warrants additional dose-response in vivo studies.