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Osteoarthritis (OA), a major cause of pain and disability, is a serious public issue worldwide. Some microRNAs (miRNAs) and SOX9 have been found to be expressed in OA. Therefore, the aim of this study is to investigate effects of microRNA-384-5p (miR-384-5p) on cartilage cell proliferation and apoptosis in mice with OA by targeting SOX9 through the NF-κB signaling pathway. First, bioinformatics was used to predict the SOX9-mediated miRNA (miR-384-5p), and dual luciferase reporter gene assay was conducted to further verify the relationship between miR-384-5p and SOX9. Then, the expression of miR-384-5p, SOX9, and NF-kB in mice modeled with OA was detected. To investigate the specific mechanism of miR-384-5p in OA, mimic and inhibitor of miR-384-5p and siRNA against SOX9 were used to transfect cartilage cells. Finally, proliferation, cell cycle, and cell apoptosis were detected using MTT assay and flow cytometry, respectively. Our results indicated that OA mice exhibited decreased expression of SOX9 and NF-kB but higher miR-384-5p expression. In addition, over-expressed miR-384-5p or silenced SOX9 could inhibit cell proliferation, and block cell cycle entry and induces apoptosis. SOX9 was a target gene of miR-384-5p. The NF-kB signaling pathway was inactivated after overexpression of miR-384-5p. Furthermore, we also observed that the effect of miR-384-5p inhibition was rescued when SOX9 was knocked down. The results support the view that inhibition of miR-384-5p could impede apoptosis and promote proliferation of cartilage cells through activating the NF-κB signaling pathway by promoting SOX9, thereby preventing the development of OA.