Electroacupuncture, Combined with Decellularized Nerve Scaffolds, Enhances Spinal Cord Neuron Protection and Functional Recovery in Sciatic Nerve-Injured Rats via the PI3K/Akt/NGF Pathway

Abstract Background We investigated the therapeutic efficacy and mechanisms of action of electroacupuncture (EA) combined with acellular scaffolds (AS) in spinal cord neurons in rats with sciatic nerve injury (SNI) by focusing on the PI3K/Akt/NGF signaling pathway. Methods Sixty male Sprague–Dawley rats were randomized into five groups: normal control (N), SNI model (M), AS alone (AS), AS + 2-week EA (EAS1), and AS + 4-week EA (EAS2). SNI was induced by excising a 10-mm segment of the right sciatic nerve. The AS was grafted to bridge the nerve defects. EA (1 Hz/20 Hz, 1 mA, 15 min/day) was applied at acupoints GB34 (“Yanglingquan”) and GB30 (“Huantiao”). The sciatic functional index (SFI), nerve conduction velocity (NCV), spinal cord histology (hematoxylin–eosin staining), and NGF and p-Akt1 levels were analyzed. Results The SFI and conduction velocity of the sciatic nerve were significantly lower in the model group than in the normal group ( P < 0.01). Light microscopy revealed that the structure of the spinal cord was loose, the cell body of the anterior horn was significantly reduced, the nucleus was deviated or displaced, and many vacuoles were present. NGF and p-Akt1 levels were significantly reduced ( P < 0.01). The SFI and sciatic NCV in the AS, EAS1, and EAS2 groups were significantly higher than those in the model group ( P < 0.01). Injury to the spinal anterior horn cells gradually weakened, and the structure became relatively ordered. NGF and p-Akt1 levels increased ( P < 0.01). Compared with that observed in the AS group, SFI and sciatic NCV were significantly higher ( P < 0.01), the morphological structure of the spinal anterior horn cells gradually recovered, and NGF and p-Akt1 levels were higher in the EAS1 and EAS2 groups ( P < 0.05). The SFI, sciatic NCV, and NGF and p-Akt1 levels in the EAS2 group were significantly higher than those in the EAS1 group ( P < 0.05). Conclusion EA, combined with AS, promotes functional recovery and neuronal repair in rats with SNI, with NGF upregulation associated with activation of the PI3K/Akt pathway. Prolonged EA administration (4 weeks) yielded superior outcomes, suggesting a time-dependent therapeutic effect. Graphical Abstract