Physalin A alleviates intervertebral disc degeneration via anti-inflammatory and anti-fibrotic effects

Background: The incidence of intervertebral disc degeneration (IVDD) is a common degenerative disease with inflammation, decreased Autophagy, and progression of fibrosis as its possible pathogenesis. Physalin A (PA) is a widely studied anti-inflammatory drug. However, its therapeutic effects on IVDD remain unexplored. Therefore, we aimed to explore the therapeutic potential of PA in IVDD progression.

Materials and methods: In vivo, we investigated PA bioactivity using a puncture-induced IVDD rat model. IVDD signals and height changes were detected using X-ray, micro-CT, and MRI, and structural and molecular lesions using histological staining and immunohistochemistry of intervertebral disc sections. In vivo, interleukin-1 beta (IL-1β) and TGF-β1 were employed to establish inflammation fibrotic nucleus pulposus (NP) cells. The PA effect duration, concentration, influence pathways, and pathological changes in IVDD treatment were elucidated using western blotting, Real-Time PCR, and immunofluorescence.

Results: PA exerted significant effects on IVDD remission due to anti-inflammation, fibrosis reduction, and Autophagy enhancement. In vitro, PA improved inflammation by blocking the NF-κB and MAPK pathways, whereas it promoted Autophagy via the PI3K/Akt/mTOR pathway and affected fibrotic progression by regulating the SMAD2/3 pathway. Moreover, PA improved the disc degeneration process in IVDD model.

Conclusions: PA exhibited significant anti-inflammatory and anti-fibrotic effects and improved Autophagy in vivo and in vitro IVDD models, thus effectively relieving IVDD progression, indicating it is a promising agent for IVDD treatment.

The translational potential of this article: This study successfully reveals that PA, a natural bioactive withanolide, effectively relieved IVDD progression via inflammation inhibition, fibrosis reduction, and Autophagy enhancement, indicating it is a promising agent for IVDD treatment.

Autophagy; Fibrosis; Inflammation; Intervertebral disc degeneration; Physalin A.