Human Umbilical Cord Mesenchymal Stem Cells Ameliorate Diabetic Neuropathic Pain via TRPV1‐[Ca ²⁺ ]i‐AMPK Signaling‐Mediated Mitochondrial Restoration in Schwann Cells

Background The therapeutic potential of human umbilical cord mesenchymal stem cells (HUCMSCs) for diabetic peripheral neuropathy (DPN) and the underlying mechanisms involving transient receptor potential vanilloid 1 (TRPV1) signaling remain incompletely defined. Objective This study aimed to elucidate the role of the TRPV1‐[Ca 2+ ]i‐AMPK signaling axis in mediating the beneficial effects of HUCMSCs on neuropathic pain and Schwann cell (SC) dysfunction in DPN. Methods A murine model of DPN was established. Mechanical allodynia and thermal hyperalgesia were assessed using Von Frey filaments and the KW‐LB hot plate test, respectively. Primary mouse SCs were isolated and cultured under high glucose (HG) conditions. Intracellular calcium ([Ca 2+ ]i) levels were quantified by flow cytometry. Protein expression (TRPV1, p‐TRPV1, AMPK, p‐AMPK, cleaved‐caspase‐3, Bax, Bcl‐2, Drp1, PGC‐1α, TFAM, Mfn2) was analyzed via Western blotting. Apoptosis and cell proliferation were evaluated using TUNEL staining and the CCK‐8 assay, respectively. Specific inhibitors (AMG9810 for TRPV1 and compound C for AMPK) were employed to probe pathway involvement. Results HUCMSC administration significantly alleviated mechanical allodynia and thermal hyperalgesia in diabetic mice. In vitro, HUCMSC coculture counteracted HG‐induced effects in SCs by: (1) increasing the p‐TRPV1/TRPV1 ratio and [Ca 2+ ]i influx (effects blocked by AMG9810); (2) reducing apoptosis (decreased cleaved‐caspase‐3/Bax, increased Bcl‐2); (3) enhancing the p‐AMPK/AMPK ratio (attenuated by both AMG9810 and compound C); and (4) promoting mitochondrial homeostasis, increasing PGC‐1α, TFAM, and Mfn2 expression, mitochondrial membrane potential and ATP levels, and decreasing Drp1 expression. These mitochondrial improvements were reversed by compound C. Conclusion HUCMSCs ameliorate diabetic neuropathic pain primarily through activation of the TRPV1‐[Ca 2+ ]i‐AMPK signaling pathway in SCs, which may provide a new molecular target for enhancing the clinical therapeutic effect of HUCMSCs on DPN.