The effect of TEMPOL pretreatment on postoperative cognitive function, inflammatory response, and oxidative stress in aged rats under sevoflurane anesthesia

INTRODUCTION: The heterocyclic compound 4‐hydroxy‐(2,2,6,6‐Tetramethylpiperidin‐1‐yl)oxyl (TEMPOL) has a protective effect on neurological function in brain tissues damaged by ischemia and hypoxia. This study explored the effects of TEMPOL pretreatment on postoperative cognitive function in aged rats under sevoflurane anesthesia, focusing on inflammatory response and oxidative stress. METHODS: Sixty male rats were divided into normal control (C), sevoflurane anesthesia (S), TEMPOL pretreatment (T), and sevoflurane anesthesia + TEMPOL pretreatment (ST) groups (15 per group). Groups T and ST rats received continuous intraperitoneal TEMPOL (100 mg/kg) for 3 days, while groups C and S rats were injected with 0.9% saline. After pretreatment, groups S and ST received 3% sevoflurane anesthesia. RESULTS: Rats in group S exhibited a longer swimming distance, longer escape latency, lower frequency of platform crossing, and shorter dwell time in the targeted quadrant than those in groups C and T. Rats in group ST exhibited a shorter swimming distance, shorter escape latency, higher frequency of platform crossing, and longer dwell time in the targeted quadrant than those in group S. The expressions of interleukin‐6, tumor necrosis factor‐α, inducible nitric oxide synthase, and Ym1/2 messenger ribonucleic acid were higher in groups S and ST rats than in groups C and T rats and lower in group ST rats than in group S rat (p < .05). Superoxide dismutase (SOD), total antioxidant capacity (T‐AOC), and glutathione peroxidase (GSH‐Px) were lower, while malondialdehyde (MDA) was higher in groups S and ST rats than in groups C and T rats (p < .05). Group ST showed higher SOD, T‐AOC, and GSH‐Px, and lower MDA than group S (p < .05). CONCLUSIONS: TEMPOL pretreatment attenuated postoperative cognitive impairment induced by sevoflurane anesthesia in aged rats. This may be attributed to the downregulation of NR2B‐CREB‐BDNF pathway, reducing the inflammatory response and oxidative stress damage in hippocampal tissue.