OBJECTIVE To explore the effects of acteoside on hypoxia/reoxygena tion（H/R）-induced cardiomyocyte damage by regulating Rho family GTPase 3（Rnd3）/nuclear factor κB（NF-κB）pathway. METHODS The H 9c2 cardiomyocyte were divided into control group （no administration ，no modeling ），H/R group （only modeling ），H/R+AS-L group ，H/R+AS-M group ， H/R+AS-H group （10，30，90 μmol/L acteoside for above 3 groups firstly ，and then modeling ），H/R+pcDNA group [transfecting pcDNA （empty vector ） firstly，and then modeling] ，H/R + pcDNA-Rnd 3 group [overexpression of Rnd 3 by transfecting pcDNA-Rnd3（Rnd3 overexpression vector ）firstly，and then modeling] ，H/R+AS-H+si-NC group [transfecting si-NC （negative control）firstly，and then giving 90 μmol/L acteoside and modeling]，H/R+AS-H+si-Rnd3 group [inhibiting overexpression of Rnd 3 by transfecting si-Rnd 3 （Rnd3 small interfering RNA ） firstly，and then giving 90 μ mol/L acteoside and modeling]. After corresponding treatment ，the apoptotic rate ，release of lactate dehydrogenase （LDH），malondialdehyde（MDA）level，the activity of superoxide dismutase （SOD），the level of tumor necrosis factor α（TNF-α），interleukin 1β（IL-1β）and interleukin- 6（IL-6）， mRNA and protein expression of Rnd 3 and NF-κB subunit p65（NF-κB p65），the expression of aspartate proteolytic enzyme 3 （Cleaved Caspase- 3）protein and Cleaved Caspase- 9 protein were detected. RESULTS Different concentrations of acteoside could reduce the apoptotic rate of H/R-induced H 9c2 cardiomyocyte，the protein expressions of Cleaved Caspase- 3 and Cleaved Caspase-9，mRNA and protein expressions of NF-κB p65，the levels of LDH release and MDA ，TNF-α，IL-1β and IL-6，while increase the activity of SOD and mRNA and protein expressions of Rnd 3（P＜0.05），in a dose-dependent manner. Overexpression of Rnd 3 could decrease the apoptotic rate of H 9c2 cardiomyocyte，protein expressions of NF-κB p65，Cleaved Caspase- 3 and Cleaved Caspase- 9， the levels of LDH release ， MDA， TNF-α，IL-1β and IL-6，while increase the protein expression of Rnd 3 and the activity of SOD （P＜0.05）. The inhibition overexpression of Rnd 3 could weaken the inhibitory effects of acteoside on H/R-induced apoptosis of H 9c2 cardiomyocyte， oxidative stress and inflammatory reaction （P＜0.05）. CONCLUSIONS Acteoside could regulate Rnd 3/NF-κ B pathway by promoting the expression of Rnd 3 and inhibiting the expression of NF-κB p65，inhibit cardiomyocyte apoptosis ，oxidative stress and inflammation reaction so as to relieve the H/R-induced cardiomyocyte damage.