CASP3 and intervertebral disk degenerative disorder: Importantly, IHC staining for cleaved caspase-3, β-catenin, and collagen II showed that in IDD and IDD + LV-NC groups, cleaved caspase-3 and β-catenin expression levels were increased, while the expression level of collagen II decreased significantly, indicating that NPC apoptosis and ECM catabolism increased in the process of IDD.