1. In vitro: miR-129–5p in MSC-EVs decreasing apoptosis, ECM degradation, and M1 polarization of macrophages via targeting LRG1 and suppressing the p38 MAPK signaling pathway in NPCs. 2. In vivo: relieving IDD via inhibition of the LRG1/p38 MAPK signaling. Here, LRG1 is linked to intervertebral disk degenerative disorder.