Rho　kinase　(ROCK)　was　the　first　downstream　Rho　effector　found　to　mediate　RhoA-induced　actin　cytoskeletal　changes　through　effects　on　myosin　light　chain　phosphorylation.　There　is　abundant　evidence　that　the　ROCK　pathway　participates　in　the　pathogenesis　of　retinal　endothelial　injury　and　proliferative　epiretinal　membrane　traction.　In　this　study,　we　investigated　the　effect　of　the　ROCK　pathway　inhibitor　Y-27632　on　retinal　Muller　cells　subjected　to　hypoxia　or　oxidative　stress.　Muller　cells　were　subjected　to　hypoxia　or　oxidative　stress　by　exposure　to　CoCl2　or　H2O2.　After　a　24-hour　treatment　with　Y-27632,　the　3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl　tetrazolium　bromide　assay　was　used　to　assess　the　survival　of　Muller　cells.　Hoechst　33258　was　used　to　detect　apoptosis,　while　2＇,7＇-dichlorodihydrofluorescein　diacetate　was　used　to　measure　reactive　oxygen　species　generation.　A　transwell　chamber　system　was　used　to　examine　the　migration　ability　of　Muller　cells.　Western　blot　assay　was　used　to　detect　the　expression　levels　of　alpha-smooth　muscle　actin,　glutamine　synthetase　and　vimentin.　After　treatment　with　Y-27632,　Muller　cells　subjected　to　hypoxia　or　oxidative　stress　exhibited　a　morphology　similar　to　control　cells.　Y-27632　reduced　apoptosis,　alpha-smooth　muscle　actin　expression　and　reactive　oxygen　species　generation　under　oxidative　stress,　and　it　reduced　cell　migration　under　hypoxia.　Y-27632　also　upregulated　glutamine　synthetase　expression　under　hypoxia　but　did　not　impact　vimentin　expression.　These　findings　suggest　that　Y-27632　protects　Muller　cells　against　cellular　injury　caused　by　oxidative　stress　and　hypoxia　by　inhibiting　the　ROCK　pathway.