The ethyl acetate extract of Schefflera kwangsiensis ameliorates oxaliplatin-induced peripheral neuropathic pain via SERCA2b

Oxaliplatin (OXA) is a widely used chemotherapeutic agent whose clinical utility is limited by OXA-induced peripheral neuropathy (OIPN). Sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) transports Ca²⁺ from the cytoplasm into the endoplasmic reticulum (ER), thereby maintaining intracellular Ca²⁺ homeostasis. Schefflera kwangsiensis Merr. ex H.L. Li (SKM) is traditionally used to treat neuropathic pain conditions such as trigeminal neuralgia and sciatica, and its active component Schekwanglupaside C has been identified as a potent SERCA activator. In this study, an OIPN mouse model was established by intraperitoneal administration of OXA (4 mg·kg⁻¹) on days 1, 2, 8, 9, 15, and 16. SERCA2b mRNA and protein expression in dorsal root ganglia (DRG) were evaluated by quantitative polymerase chain reaction (qPCR) and immunofluorescence. Mechanical allodynia was assessed using the Von Frey test. DRG neuronal excitability was examined by whole-cell current-clamp recordings, whereas oxidative stress and neuronal apoptosis/necrosis were assessed using the reactive oxygen species (ROS)-sensitive probe 2',7'-dichlorofluorescin diacetate (H₂DCFDA) and fluorescein isothiocyanate (FITC)/propidium iodide (PI) dual staining. This study identifies SERCA2b as a novel therapeutic target for OIPN. We observed that SERCA2b mRNA and protein levels were significantly downregulated during OIPN progression. Treatment with the SERCA agonist CDN1163 (CDN), the ethyl acetate extract of SKM (SKM.Ext), or duloxetine (DLX) attenuated neuronal pathology, restored DRG neuron soma diameter, and reduced the expression of pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α). Pre-incubation of DRG neurons with CDN1163 or SKM.Ext for 1 h significantly attenuated OXA-induced hyperexcitability and reduced the abnormal increase in voltage-gated sodium channel (VGSC) current density. Inhibition of oxidative stress with N-acetyl-L-cysteine (NAC) significantly restored SERCA expression in OIPN, indicating that oxidative stress downregulates SERCA2b in DRG. Collectively, these findings demonstrate that activation of SERCA2b by CDN1163 or Schefflera kwangsiensis extract enhances SERCA2b expression, reduces DRG neuronal sensitization, and alleviates OIPN. This work supports SERCA2b as a novel therapeutic target for OXA-induced neuropathy and expands the potential clinical analgesic indications of Schefflera kwangsiensis.