Objective:To investigate whether miR-9 plays a role in regulating glycogen synthase kinase-3β (GSK-3β) expression, affecting Wnt/β-catenin pathway activity and the patho-genesis of Osteo-arthritis (OA).Methods:The cartilage tissue of OA patients and normal cartilage tissue after traumatic amputation were collected, and the expressions of miR-9 and GSK-3β were compared. The double luciferase gene reporting test verified whether there was a targeted regulatory relationship between miR-9 and GSK-3β. OA rat model was established and compared with sham group, enzyme-linked immuno sorbent assay (ELISA) was used to detect hydroxyproline (Hyp) content in joint fluid.A kit was used to detect caspase-3 activity, and miR-9 and GSK-3β expression differences were detected in cartilage tissue. The OA model rats were divided into 3 groups: the sham group, the OA+ antagomiR-NC group, the OA + antagomiR-9 group. ELISA was used to detect Hyp content in joint fluid, kit was used to detect caspase-3 activity, and flow cytometry was used to detect cell cartilage tissue. Apoptosis, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to detect the expression of miR-9, GSK-3β, β-catenin and COL2A1. The comparison of mea-surement data between the two groups was conducted by t-test. The comparison of measurement data between multiple groups was conducted by one-way Analysis of Variance (ANOVA) analysis of variance, and then Bon-ferroni method was used for comparison between the two groups. P<0.05 was considered as statistically sign-ificant. Results:The miR-9 expression of cartilage tissue were (1.09±0.25) in the control group, and (2.86±0.25) in the OA group ( t=24.30, P<0.01). The GSK-3 β mRNA expression of cartilage tissue was (0.99±0.11) in the control group, and (0.53±0.10) in the OA group ( t=15.40, P<0.01). There was a targeted regulatory relationship between miR-9 and GSK-3β. The miR-9 expression of cartilage tissue was (1.00±0.21) in the sham group, and (2.61±0.36) in the OA group (t=9.462, P<0.01). The GSK-3 β mRNA expression of cartilage tissue was (1.00±0.18) in the sham group, and (0.52±0.09) in the OA group ( t=5.842, P <0.01). The Hyp content of joint fluid was (10±3) ng/ml in the sham group, and (50±8) ng/ml in the OA group ( t=11.015, P<0.01). The Caspase-3 activity of cartilage tissue was (1.00±0.19) in the sham group, and (2.43±0.36) in the OA group ( t=8.605, P<0.01). The miR-9 expression of cartilage tissue was (2.86±0.31) in the OA+antagomir NC group, and (1.67±0.19) in the OA + antagomir-9 group ( F=105.2, P<0.01). The GSK-3β mRNA expression of cartilage tissue was (0.41±0.09) in the OA antagomir NC group, and (0.81±0.09) in the OA + antagomir-9 group ( F=49.32, P<0.01). The Hyp content of joint fluid was (52.3±6.8) ng/ml in the OA + antagomir NC group, and (30.3±3.4) ng/ml in the OA + antagomir-9 group ( F=119.7, P<0.01). The caspase-3 activity of cartilage tissue was (2.22±0.23) in the OA + antagomir NC group, and (1.43±0.14) in the OA+ antagomir NC group ( F=72.55, P<0.01). Compared with OA + antagomir NC group, the expression of β-Catenin protein in the OA + miran-tagomir-9 group wasdecreased, the expression of GSK-3 β and COL2A1 protein wasincreased, and cell apo-ptosis wasdecreased. Conclusion:The increased expression of miR-9 plays a role in reducing the expression of GSK-3β, enhancing the activity of Wnt/β-catenin pathway, promoting the degradation, destruction of cartilage matrix and the pathogenesis of OA. Inhibition of miR-9 expression can reduce the protective effect of OA.