SB772077B (SB77) Alleviated the Aqueous Outflow Resistance Mediated by Cyclic Mechanical Stress in Perfused Human Cadaveric Eyes

The intraocular pressure lowering property of a new rho kinase inhibitor, SB772077B (SB77) has been previously demonstrated in perfused human cadaveric eyes. In this study, the efficacy of SB77 in alleviating the aqueous outflow resistance mediated by cyclic mechanical stress in perfused human cadaveric eyes was investigated. A human anterior segment perfusion culture model was used to investigate the effect of cyclic intraocular pressure (IOP) on aqueous outflow facility in presence or absence of SB77. The status of RhoA activation and the downstream effector molecule myosin-light chain phosphorylation (p-MLC) was investigated by Western blot. Cyclic mechanical stress resulted in decrease in aqueous outflow facility (–19.79 ± 4.93%; p = 0.019) in perfused human eyes and treatment with SB77 (50 µM) significantly enhanced outflow facility by 15% (p = 0.05). The increase in outflow facility by SB77 was confirmed with the inactivation of RhoA/ROCK signaling and decreased expression of extracellular matrix markers. SB77 effectively reduced the outflow resistance mediated by cyclic IOP and thus may be a potential clinical candidate for the management of glaucoma.