BACKGROUND: Intervertebral disc degeneration (IVDD) is the main pathological basis of low back pain, and its occurrence is closely related to the dysfunction of nucleus pulposus cells (NPCs). Although several studies have investigated the role of oxidative stress, apoptosis, and inflammation in IVDD, the specific molecular mechanisms underlying the regulation of pyroptosis and mitophagy remain unclear. This study aims to explore the effect and molecular mechanism of Duhuo Jisheng Decoction (DHJS) and its active component Acacetin (ACA) against IVDD.
METHODS: In this study, the therapeutic effects of DHJS on IVDD were first evaluated both in vitro and in vivo using histological staining, Western blotting, ROS detection, and flow cytometry. Ultra-high-performance Liquid Chromatography coupled with Quadrupole-Orbitrap High-Resolution Mass Spectrometer (UHPLC-QE-MS) was employed to identify the active components of DHJS that entered systemic circulation. The role of ACA, a key bioactive compound, in regulating NPCs pyroptosis and mitophagy was further investigated through ROS staining, JC-1 mitochondrial membrane potential assay, flow cytometry, and Western blotting. Potential targets of ACA and mitogen-activated protein kinase 1(MAPK1) were identified using network pharmacology and mass spectrometry analysis. Finally, the therapeutic efficacy of ACA was validated in a rat model of IVDD.
RESULTS: It was found that DHJS could significantly alleviate the pathological process of IVDD by inhibiting NPCs pyroptosis. Further studies revealed that ACA, the key active component of DHJS, directly bound to MAPK1 and inhibited its expression, thereby relieving the negative regulation of MAPK1 on heme oxygenase 1 (HMOX1). This interaction enhanced NPCs mitophagy and ultimately suppressed pyroptosis. Notably, this is the first study to identify the Acacetin-MAPK1/HMOX1 axis as a regulatory pathway linking mitophagy and pyroptosis in IVDD. In vivo experiments further confirmed that ACA could reverse the collagen fiber disorder, proteoglycan reduction and enhanced expression of mitophagy-related proteins in the intervertebral disc tissue of IVDD rats.
CONCLUSION: This study reveals a new mechanism by which DHJS regulates the function of NPCs through the Acacetin-MAPK1/HMOX1-mitophagy-pyroptosis axis. These findings not only provide a theoretical basis for traditional Chinese medicine intervention in IVDD but also broaden the understanding of mitophagy-pyroptosis crosstalk as a potential strategy for degenerative disc disease therapy.
