BACKGROUND: Intervertebral disc degeneration (IVDD) is a prevalent and debilitating condition characterized by loss of nucleus pulposus cells (NPCs) and degradation of the extracellular matrix (ECM). While the traditional Chinese medicine (TCM) formula Danggui Niantong decoction (DGNTD) has shown promise in treating IVDD and other arthritic conditions, its precise mechanisms of action remain unclear. This study aimed to define the therapeutic efficacy of DGNTD and its active constituent, glycyrrhetinic acid, against IVDD and to elucidate their underlying molecular mechanisms.
METHODS: The systemic bioavailability of DGNTD components was assessed by UPLC-MS/MS. Network pharmacology, RNA sequencing (RNA-seq), molecular docking, and molecular dynamics simulation were used to explore the potential targets and mechanisms of DGNTD against IVDD. An IVDD model was induced in rats through annulus fibrosus puncture (AFP). The protective effects of DGNTD-treated serum and glycyrrhetinic acid were evaluated in vitro using a tert‑butyl hydroperoxide (TBHP)-stimulated NPC model.
RESULTS: UPLC-MS/MS analysis identified 8 principal constituents of DGNTD in serum. In vivo, DGNTD treatment significantly attenuated the progression of IVDD in a rat AFP model. Integrated network pharmacology and RNA-seq analyses proposed that the therapeutic effects of DGNTD-treated serum on IVDD likely involve the modulation of cellular senescence, apoptosis, and autophagy. Corresponding in vitro studies confirmed that DGNTD-treated serum enhanced ECM anabolism while suppressing catabolism in NPCs. Furthermore, DGNTD-treated serum mitigated TBHP-induced mitochondrial impairment, cellular senescence, and apoptosis. Finally, we established that DGNTD's protective effects are mediated through the induction of autophagy, as evidenced by enhanced autophagic flux and the abolition of these benefits upon inhibition of autophagy-related 7 (ATG7). Molecular docking, molecular dynamics simulations, and surface plasmon resonance (SPR) demonstrated that glycyrrhetinic acid, a key bioactive component of DGNTD, exhibits strong binding stability with mitogen-activated protein kinase 3 (MAPK3) and inhibits its expression. The glycyrrhetinic acid-MAPK3 interaction enhanced NPC autophagy and ultimately suppressed cellular senescence and apoptosis.
CONCLUSIONS: This study deciphers the multi-target, multi-pathway mechanisms underline the DGNTD in the treatment of IVDD, integrating TCM principles with modern pharmacology. The identified bioactive components and pathways provide a scientific foundation for clinical usage of DGNTD and indicate the importance of targeting autophagy in the treatment of IVDD. These findings provide a mechanistic basis for the therapeutic application of DGNTD in IVDD, positioning it as a promising candidate for mitigating disease progression.
