Obacunone Promotes Functional Recovery After Spinal Cord Injury by Attenuating Neuroinflammation by Targeting the TLR4/MyD88/p38 MAPK Pathway.

PURPOSE: Spinal cord injury (SCI) triggers a complex secondary injury process, among which inflammation and apoptosis are the key factors of nerve injury. Obacunone (Oba) is a natural limonoid that has demonstrated a variety of pharmacological effects, but its role in SCI remains unclear.

METHODS: Network pharmacology and bioinformatics analysis were employed to predict the functions and mechanisms of Oba in SCI. Subsequently, in vivo validation was conducted in a mouse SCI model, with motor function recovery assessed using open field, footprint, and swimming tests. Spinal cord histomorphology was examined via hematoxylin and eosin (HE) staining and Nissl staining, while the anti‑inflammatory and anti‑apoptotic effects were evaluated by Western blot and immunofluorescence. To further elucidate the underlying mechanisms, a lipopolysaccharide (LPS)-induced inflammatory model in BV‑2 microglial cells was established to study the anti‑inflammatory mechanisms of Oba. Furthermore, a BV‑2/HT22 neuronal co‑culture system was constructed to investigate neuroprotective effects of Oba against apoptosis.

RESULTS: In vivo, Oba treatment improved motor function, promoted neural repair, reduced inflammation and apoptosis. Correspondingly, Oba suppressed the expression of LPS-induced pro-inflammatory cytokines in BV-2 cells. In a microglia-neuron co-culture system, Oba protected HT22 neurons from microglia-mediated inflammatory apoptosis. Mechanistically, the anti‑inflammatory effects of Oba were mediated by inhibiting the activation of the TLR4/MyD88/p38 MAPK pathway.

CONCLUSION: This study identifies Oba as an effective compound that mitigates secondary injury by reducing inflammation and apoptosis and promotes nerve repair and functional recovery post-SCI, supporting its potential for further therapeutic development.