This study was aimed to research the effect of miR-223 on the inflammatory responses induced by lipopolysaccharide (LPS) in nucleus pulposus (NP) cells of rat intervertebral disc. Isolated rat NP cells were induced by LPS. Reverse transcriptase quantitative real-time polymerase chain reaction was used to detect gene expression. To detect protein expression， Western blot and enzyme-linked immunosorbent assay experiments were applied. The putative targeting relationship between miR-223 and Irak1 was determined using dual-luciferase reporter gene assay. We found that miR-223 was downregulated in LPS-induced NP cells. MiR-223 upregulated the expression of extracellular matrix-related genes (Aggrecan and Collagen II). Matrix degrading enzymes (ADAMTS4， ADAMTS5， MMP3 and MMP13)， NO reaction-associated proteins (PGE2， COX-2 and INOS) and the expression of nuclear factor (NF)-κB signaling-related proteins were downregulated after miR-233 overexpression. In addition， luciferase reporter assays demonstrated that miR-223 directly targeted Irak1. MiR-223 overexpression could inhibit NF-κB signaling by targeting Irak1， and finally suppress the LPS-induced inflammation in NP cells. © 2018 IUBMB Life， 70(6):479-490， 2018.