Intervertebral disc degeneration (IVDD) is a main cause of low back pain, and inflammatory factors play key roles in its pathogenesis. Gremlin-1 (Grem1) was reported to induce an inflammatory response in other fields. This study aimed to investigate the mechanisms of Grem1 in the degenerative process of intervertebral discs. Dysregulated genes were determined by analyzing microarray profiles. The expression of Grem1 in 17 human disc samples (male:female = 9:8) and rat models (n = 5 each group) was measured by western blotting (WB), real-time quantitative PCR (RT-qPCR), and immunohistochemistry (IHC). The regulatory effects of Grem1 on apoptosis were examined using siRNAs, flow cytometry, immunofluorescence (IF), and WB. The therapeutic effect was evaluated by locally injecting specific Grem1 siRNA into IVDD rats. The expression of Grem1 was significantly increased in human degenerative intervertebral discs; furthermore, the expression of Grem1 positively correlated with the level of intervertebral disc degeneration. Grem1 was significantly overexpressed in tumor necrosis factor (TNF)-α-induced degenerative NP cells. Apoptosis in degenerative NP cells transfected with siRNA targeting Grem1 was significantly lower than that in the control group. Specific Grem1 siRNA markedly repressed the development of IVDD in surgery-induced IVDD rats. These results indicated that the expression of Grem1 was positively correlated with the severity of intervertebral disc degeneration, and Grem1 siRNA could inhibit Grem1-induced apoptosis and extracellular matrix alterations by mediating the TGF-β/Smad signaling pathway. This study may provide a therapeutic strategy for alleviating inflammation-induced apoptosis associated with intervertebral disc degeneration.

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This study investigated the molecular mechanism by which acetylshikonin inhibits SOX4 expression via the PI3K/Akt pathway to delay intervertebral disc degeneration (IVDD) and low back pain (LBP). Bulk RNA‐seq, RT‐qPCR, Western blot analysis, immunohistochemical staining, small interfering RNA (siSOX4), lentivirus (lentiv‐SOX4hi), and imaging techniques were used to assess SOX4 expression and validate its upstream regulatory pathway. Acetylshikonin and siSOX4 were injected into the IVD to measure IVDD. SOX4 expression significantly increased in degenerated IVD tissues. TNF‐α increased SOX4 expression and apoptosis‐related proteins in nucleus pulposus cells (NPCs). siSOX4 reduced TNF‐α‐induced NPCs apoptosis, while Lentiv‐SOX4hi increased it. The PI3K/Akt pathway was significantly correlated with SOX4, and acetylshikonin upregulated PI3K/Akt pathway while inhibiting SOX4 expression. In the anterior puncture IVDD mouse model, SOX4 expression was upregulated, and acetylshikonin and siSOX4 delayed IVDD‐induced LBP. Acetylshikonin delays IVDD‐induced LBP by inhibiting SOX4 expression through the PI3K/Akt pathway. These findings offer potential therapeutic targets for future treatments.