BACKGROUND:MiR-338-3p could inhibit osteoclast differentiation,and downregulation of receptor activator of nuclear factor-κB ligand level could promote bone formation.However,it is unclear whether miR-338-3p can affect the proliferation and apoptosis of alveolar bone osteoblasts by regulating the receptor activator of nuclear factor-κB ligand level. OBJECTIVE:To explore the effect and mechanism of miR-338-3p on proliferation and apoptosis of alveolar bone osteoblasts by targeting receptor activator of nuclear factor-κB ligand. METHODS:Human alveolar bone osteoblasts were isolated,transfected and treated with Wnt-C59(Wnt/β-catenin pathway inhibitor),and divided into transfection control group,miR-338-3p group,miR-338-3p+control group,miR-338-3p+receptor activator of nuclear factor-κB ligand group and miR-338-3p+Wnt-C59 group.The dual luciferase report experiment was used to verify the regulatory effect of miR-338-3p on receptor activator of nuclear factor-κB ligand.Cell counting kit-8 and 5-Ethynyl-2'-deoxyuridine staining were used to detect cell proliferation levels.Flow cytometry was used to detect cell cycle and apoptosis levels.RT-qPCR was used to detect miR-338-3p,receptor activator of nuclear factor-κB ligand,Wnt-3a,β-Catenin,glycogen synthase kinase-3β mRNA levels.Western blot was used to detect RANKL,proliferating cell nuclear antigen,Ki67,CyclinD1,B-cell lymphoma/leukemia-2,B-cell lymphoma-2 related X protein,Caspase3,Wnt-3a,β-catenin,glycogen synthase kinase-3β protein levels. RESULTS AND CONCLUSION:miR-338-3p could target the regulation of receptor activator of nuclear factor-κB ligand.After overexpression of miR-338-3p,cell survival rate,5-Ethynyl-2'-deoxyuridine positive cell rate,proportion of S-phase cells were increased,and apoptosis rate was decreased.The mRNA and protein levels of miR-338-3p,proliferating cell nuclear antigen,Ki67,CyclinD1,B-cell lymphoma/leukemia-2,Wnt-3a,and β-catenin were increased,while the mRNA and protein levels of B-cell lymphoma-2 related X protein,Caspase3 protein,receptor activator of nuclear factor-κB ligand,and glycogen synthase kinase-3β were decreased(all P<0.05).Overexpression of receptor activator of nuclear factor-κB ligand or Wnt-C59 could weaken the effects of overexpression of miR-338-3p on cell proliferation and apoptosis(all P<0.05).Overall,miR-338-3p promotes alveolar bone osteoblast proliferation and inhibits apoptosis by targeting receptor activator of nuclear factor-κB ligand,which may act through activation of the Wnt/β-catenin signaling pathway.