Oxygen-controllable injectable hydrogel alleviates intervertebral disc degeneration by balancing extracellular matrix metabolism.

Nucleus pulposus (NP) cells, situated at the core of intervertebral discs, have acclimated to a hypoxic environment, orchestrating the equilibrium of extracellular matrix metabolism (ECM) under the regulatory influence of hypoxia inducible factor-1α (HIF-1α). Neovascularization and increased oxygen content pose a threat, triggering ECM degradation and intervertebral disc degeneration (IVDD). To address this, our study devised an oxygen-controllable strategy, introducing laccase into an injectable and ultrasound-responsive gelatin/agarose hydrogel.