Electroacupuncture Pretreatment Ameliorates Perioperative Neurocognitive Disorder in Aged Mice by Inhibiting Ferroptosis Through the SIRT1/NRF2/GPX4 Pathway.

Perioperative neurocognitive disorder (PND) is a common complication after anesthesia surgery in elderly patients, which not only reduces the patients' quality of life but also increases the burden on their families and society. PND has been found to be closely related to ferroptosis. This study investigated whether electroacupuncture (EA) can inhibit ferroptosis through the SIRT1/NRF2/GPX4 pathway to improve PND in aged mice. The PND model was established using sevoflurane anesthesia and tibial fracture surgery. EA was administered at the Baihui (GV 20) and Dazhui (GV 14) acupoints. Additionally, intraperitoneal injection of silent information regulator sirtuin 1 (SIRT1) inhibitor EX527 (5 mg/kg) was administered for five consecutive days before surgery and intraperitoneal injection of ferrostatin-1 (Fer-1) (2 mg/kg) was administered before anesthesia. On the third day after surgery, the cognitive ability of the aged mice was measured using the Y-maze, and motor ability was assessed by total distance in the open field test. Transmission electron microscopy was used to observe hippocampal mitochondrial structure. Immunofluorescence staining was used to detect glutathione peroxidase 4 (GPX4) levels in the hippocampus. Flow cytometry measured ATP content and mitochondrial membrane potential in hippocampal mitochondria. A colorimetric assay was used to detect iron content in hippocampal neurons. Reverse transcription-quantitative polymerase chain reaction and Western blotting were used to detect mRNA and protein expression of Solute carrier family 7 member (SLC7A11), transferrin receptor 1 (TFR1), iron regulatory protein 2 (IRP2), ferritin, SIRT1, nuclear factor erythroid 2-related factor 2 (NRF2) and GPX4. The results showed that compared with the model group, the EA treatment group and the Fer-1 (iron inhibitor) treatment group revealed improved ferroptosis and memory function in hippocampal neurons, while the EX527 (SIRT1 inhibitor) treatment group did not reveal any improvement. In conclusion, the occurrence and progression of PND are closely related to ferroptosis. EA stimulation of the Baihui and Dazhui acupoints can improve PND, possibly by regulating ferroptosis through the SIRT1/NRF2/GPX4 signalling pathway.