Tetrandrine attenuates diabetic neuropathic pain by suppressing ferroptosis and inflammation via Alox15 modulation

Diabetic neuropathic pain (DNP) is a common, debilitating complication of diabetes with limited disease-modifying therapies. Regulated Ferroptosis in neuroimmune signaling that sustains central sensitization. We investigated whether tetrandrine (Tet), a bis-benzyl-isoquinoline alkaloid with anti-inflammatory properties, mitigates DNP by targeting ferroptotic and inflammatory pathways in the spinal cord and investigate the potential molecular mediator. We found that systemic Tet treatment markedly reduced mechanical allodynia in DNP rats and suppressed spinal glial activation and proinflammatory cytokine secretion. RNA-seq revealed Tet-reversed transcriptional changes enriched in immune pathways, with Alox15 among Tet-responsive genes, which involved in Ferroptosis. In DNP rat spinal cord, Tet lowered spinal MDA and Fe²⁺, restored GPX4 and ferritin subunit expression, and reduced Alox15 upregulation. In rat microglial cells (RMCs), Tet rescued Erastin-induced Ferroptosis, improved viability, reduced ROS, MDA, Fe²⁺, cytokine release, and preserved mitochondrial ultrastructure. Forced Alox15 overexpression abolished Tet's cytoprotective effects, reinstating Ferroptosis and inflammatory signaling. Collectively, our findings uncover the mechanism that Tet mitigates DNP-associated mechanical allodynia by restraining spinal Ferroptosis, with Alox15 acting as a key counter-regulator of Tet's protective action.