Effect of heme oxygenase 1 on the apoptosis of human degenerated nucleus pulposus cells induced by tumor necrosis factor α

To investigate the effect of heme oxygenase 1 (HO-1) on the apoptosis of human degenerated nucleus pulposus (NP) cells induced by tumor necrosis factor α (TNF-α), and explore its possible molecular mechanism. The intervertebral disc tissues were derived from patients with lumbar intervertebral disc herniation. Then, the NP cells were cultured and the third generation of NP cells were used for subsequent experiments. Cell counting kit 8 (CCK-8) method was used to observe the proliferative effect of TNF-α on the NP cells at the concentration of 10, 20, 50, 100, and 200 ng/mL. The most apropriate concentration was selected according to the result of CCK-8. The NP cells were cultured with basal medium (control group), TNF-α (TNF-α group), TNF-α and CoPP 10 μmol/L (CoPP group), and TNF-α and ZnPP 15 μmol/L (ZnPP group), respectively. After cultured, the cell poptosis was detected by Hoechst staining and flow cytometry; the expression of cleaved Caspase-3, epithelial membrane protein 1 (EMP-1), HO-1, and p-P65 prot