Regulating mitochondrial dynamics balance in nucleus pulposus cells inhibits cell apoptosis

• Sirt3 overexpression inhibits TBHP-induced apoptosis and improves viability of nucleus pulposus cells. • Sirt3 restores mitochondrial dynamics balance by activating the AMPK/Drp1 pathway and suppressing excessive mitochondrial fission. • The protective effects of Sirt3 are partially reversed by AMPK inhibition, confirming pathway specificity. • Sirt3 is a promising therapeutic target for intervertebral disc degeneration.