Ozonated water attenuates nucleus pulposus cell apoptosis and matrix degradation by suppressing NF-κB signaling in a rat model of <i>Staphylococcus aureus</i> -induced discitis

Purpose Discitis is a severe suppurative infection of the intervertebral disc (IVD) posing significant clinical challenges. This study evaluated the therapeutic efficacy of ozonated water (OW) in a rat model of Staphylococcus aureus-induced discitis and elucidated its underlying mechanisms, focusing on NF-κB signaling, extracellular matrix homeostasis, and nucleus pulposus (NP) cell apoptosis.Methods A rat tail coccygeal IVD discitis model was established by injecting S. aureus (102 cfu) into the disc space. From day 3 post-infection, animals received transdiscal lavage with normal saline, levofloxacin (5 mg/mL), or OW (30 μg/mL) three times daily until day 9. In vitro, NP cells were stimulated with S. aureus Protein A (SpA, 1 μg/mL). Antibacterial activity, extracellular matrix metabolism, inflammatory cytokine expression, NF-κB p65 signaling, and apoptosis were evaluated by bacterial culture, Western blotting, immunohistochemistry, TUNEL assay, and flow cytometry.Results OW significantly alleviated tail swelling and IVD structural damage. OW demonstrated potent antibacterial activity against S. aureus, disrupting bacterial membrane integrity. OW attenuated extracellular matrix degradation by upregulating collagen II and aggrecan while downregulating MMP3 and MMP9, and suppressed inflammatory responses (IL-1β, IL-6, TNF-α, Cox2) by inhibiting NF-κB p65 phosphorylation and nuclear translocation. OW also reduced NP cell apoptosis, evidenced by decreased TUNEL-positive rate, elevated Bcl-2/Bax ratio, and reduced Cleaved caspase-3.Conclusions OW attenuates S. aureus-induced discitis through direct antibacterial action, suppression of NF-κB-mediated inflammation, protection against NP cell apoptosis, and preservation of extracellular matrix integrity, highlighting its promise as a novel lavage strategy for discitis management.