Overall, these findings further validated the involvement of <i>P. acnes</i> in the pathology of IVDD and provided evidence that <i>P. acnes</i>-induced iNOS/NO and COX-2/PGE<sub>2</sub> activation via the ROS-dependent NF-<i>κ</i>B pathway is likely responsible for the pathology of IVDD.
During the pathogenesis of intervertebral disc degeneration, pro‑inflammatory cytokines, including tumor necrosis factor‑α (TNF‑α), stimulate the degradation of the extracellular matrix (ECM) of intervertebral discs via the activity of catabolic enzymes including matrix metalloproteinases (MMPs), disintegrins and metalloproteinases with thrombospondin motifs (ADAMTSs), and cyclooxygenase 2 (Cox2).