Effect of hyperbaric oxygenation on intervertebral disc degeneration: an in vitro study with human lumbar nucleus pulposus.

Study Design. An in vitro study with degenerated human lumbar intervertebral disc specimens cultured under hyperbaric oxygenation (HBO). Objective. To observe the changes in interleukin (IL)-1 beta, prostaglandin (PG)-E2, nitric oxide (NO), cell growth, and apoptosis of the human nucleus pulposus cell (NPC) after HBO. Summary of Background Data. Intervertebral disc degeneration has been demonstrated as related to IL-1 beta, PG-E2, NO, and O-2 concentration but the actual mechanism is not clear. HBO also has also been reported in the literature to influence changes in IL-1 beta, prostaglandin E2, NO, and O-2 concentration. However, the direct effect of HBO on the disc cells has not been previously reported. Methods. We collected 12 human lumbar degenerated disc specimens and evaluated the effects of HBO on the cultured NPCs. The amounts of IL-1 beta, PG-E2, and NO in the conditioned medium were quantified by enzyme-linked immunosorbent assay and high performance liquid chromatography. Cell growth was measured by increase in cell number. Cell viability and proteoglycan content were evaluated by histologic study using safranin O staining. In situ analysis of apoptosis was performed using Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Results. Our data indicated that HBO treatment inhibited IL-1 beta, PG-E2, and NO production but increased cell number and matrix synthesis of cultured NPCs. TUNEL staining showed that HBO treatment suppressed the apoptosis of cultured NPCs. Conclusion. HBO provides a potential treatment modality for disc degeneration.