After that, the expression of HDAC4 in the mouse model was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting, which revealed that HDAC4 mRNA and protein expressions were increased in NP tissues of IDD mice when compared to control or sham mice, while there was no difference in the mRNA and protein expressions of HDAC4 between control and sham mice (Fig. 1c, d). The gene discussed is HDAC4; the disease is intervertebral disk degenerative disorder.