COL2A1 and intervertebral disk degenerative disorder: These cells are chondrocyte‐like, located in the AF, and are prone to degenerate as disc degeneration progresses.23 Because of the difficulty of obtaining enough CLCs from Col2a1‐Smurf2 transgenic discs, we employed primary old bovine NP cells that express chondrocyte‐specific matrix proteins and possess a senescent phenotype as substitutes for the CLCs to study how these cells contribute to the disc degeneration progression in Col2a1‐Smurf2 transgenic mice.