The concentration of nitric oxide (NO), interleukin (IL)‐1, interleukin (IL)‐6, and tumor necrosis factor alpha (TNF‐α) was determined using the enzyme‐linked immunosorbent assay in each sample, and the degeneration degree of the target discs were evaluated using T2‐weighted sagittal magnetic resonance imaging (MRI) according to the Miyazaki disc degeneration grading system. Here, TNF is linked to intervertebral disk degenerative disorder.