Wogonin Ameliorates the Oxidative Stress, Apoptosis, and Extracellular Matrix Degradation of Nucleus Pulposus Cells Mediated by Cutibacterium acnes via the MAPK Signaling Pathway: An In Vivo and In Vitro Study.

Intervertebral disc degeneration (IDD) is a fundamental pathological basis of low back pain, yet its pathogenic mechanisms remain incompletely understood. Infection by low-virulence anaerobic bacteria has recently been recognized as a potential etiological factor. In this study, Cutibacterium acnes (C. acnes) was detected in 13.7% of degenerated intervertebral disc (IVD) tissues, and its presence was significantly associated with younger patients and Modic changes. In vitro experiments demonstrated that C. acnes supernatant induces oxidative stress, apoptosis, and extracellular matrix (ECM) degradation in nucleus pulposus (NP) cells in a dose-dependent manner. RNA sequencing and functional validation further indicated that these pathological effects are mediated through activation of the p38 MAPK signaling pathway. Pharmacological inhibition of p38 with the specific inhibitor BIRB-796 effectively reversed the observed cellular damage. Wogonin exhibited negligible cytotoxicity toward NP cells and significantly attenuated C. acnes supernatant-induced oxidative stress, apoptosis, and ECM metabolic imbalance by inhibiting the phosphorylation of p38, JNK, and ERK1/2 within the MAPK pathway. Furthermore, in vivo experiments confirmed that Wogonin alleviated disc height loss, reduced T2-weighted signal attenuation, and mitigated histological damage induced by C. acnes in rat models, thereby restoring the balance between ECM synthesis and degradation. Collectively, this study demonstrates for the first time that C. acnes supernatant exacerbates IDD through activation of the p38 MAPK signaling pathway. It further shows that Wogonin can specifically inhibit this pathway and effectively ameliorate C. acnes-mediated IDD damage in both in vitro and in vivo models. These findings expand the theoretical framework of infection-related mechanisms underlying IDD and identify potential therapeutic targets and candidate agents for the treatment of IDD associated with C. acnes infection. Low back pain is a common health issue affecting populations worldwide, with intervertebral disc degeneration as its core etiology. However, the pathogenic causes in some patients, especially young individuals, remain incompletely understood. This study found that Cutibacterium acnes, a low-virulence bacterium commonly colonizing human skin and mucous membranes, produces metabolic products that can induce damage to the core cells of the intervertebral disc, exacerbate disc degeneration, and this process is associated with the abnormal activation of specific cellular signaling pathways. Through clinical sample detection, cell experiments, and animal model validation, we confirmed that infection with this bacterium is closely related to young patients and specific spinal imaging changes. Meanwhile, we identified Wogonin, a natural compound extracted from Scutellaria baicalensis, which can effectively inhibit the aforementioned abnormal signaling pathways, alleviate cell damage caused by bacterial metabolic products, and improve the pathological state of intervertebral disc degeneration. This study not only reveals the role of low-virulence bacterial infection in intervertebral disc degeneration and provides a new explanation for the pathogenic mechanism in young patients but also offers a natural antibiotic-free candidate for addressing bacterial resistance. It holds significant reference value for the clinical diagnosis and treatment of spinal diseases as well as the development of related drugs.