| Objective: The study was conducted to investigate the effects of perioperative electroacupuncture stimulation of Baihui and Neiguan acupoints on Sirt1/NF-κB pathway proteins and hippocampus mitochondrial function in a rat model of PND.Our study provides a scientific basis for exploring a safe and reliable way to prevent and treat cognitive dysfunction after anaesthesia and operation.Methods: Ninety-six 18-20 month old SPF grade healthy female SD rats(weight350～450 g)were divided into control group(Control group),model group(PND group),electroacupuncture group(EA group)and drug group(Resveratrol group)according to the random number table method,and each group was further divided into two subgroups according to different postoperative time points,i.e.3 days postoperative group(3d)and 7days postoperative group(7d).All groups of rats were first trained in cognitive function for 5days.The rats in the PND,EA and Resveratrol groups were subjected to exploratory laparotomy to establish the PND model at the next day after the cognitive training.Rats in the EA group received electroacupuncture stimulation of Baihui and Neiguan points for 20-30 minutes at the same time each day during the two days before surgery,the day of surgery(during surgery)and two days after surgery.Resveratrol group rats were given 10 mg/kg Resveratrol(dissolved in DMSO,diluted in saline)intraperitoneally daily for 7 days from the day cognitive function training started.Rats in the Control,PND and EA groups were injected intraperitoneally with equal doses of DMSO saline dilution daily.The behavioural results of cognitive function in rats were measured at 3 and 7 days post-operatively using the Morris water maze device.At the end of the behavioural tests,the rats were executed,and blood and brain tissue were taken for testing or preservation.The enzyme linked immunosorbent assay(ELISA)was used to measure the activity of mitochondrial respiratory chain complexes I and IV in the hippocampus and the serum concentrations of tumor necrosis factor(TNF)-α,interleukin(IL)-6 and IL-10.The changes of mitochondrial membrane potential(MMP)ΔΨm were measured by flow cytometry JC-10.The expression levels of Sirt1,NF-κB mRNA and protein were detected by quantitative real-time polymerase chain reaction(q PCR)and western blot(WB),respectively.Results: 1.The results of the Morris water maze experiment showed that: At 3 and 7 days after surgery: compared with the Control group,rats in the PND group showed an increase in escape latency and a decrease in the number of platform crossings(P < 0.05).At 3 days after surgery: compared with the PND group,the EA and Resveratrol groups showed shorter escape latency and increased number of platform crossings(P < 0.05).At 7 days after surgery:there was no significant difference in escape latency and the number of platform crossings in the EA and Resveratrol groups compared to the PND group(P > 0.05).2.The results of the ELISA experiment showed that: At 3 and 7 days after surgery: compared with the Control group,serum IL-6 and TNF-α levels were increased(P < 0.05),IL-10 levels were not significantly different(P > 0.05)and the levels of mitochondrial respiratory chain complex I and IV concentrations in the hippocampus of rats were decreased(P < 0.05)in the PND group.At 3 days after surgery: decreased serum IL-6 and TNF-α levels(P < 0.05)and increased serum IL-10 and hippocampus mitochondrial respiratory chain complexes I and IV levels(P <0.05)in rats in the EA and Resveratrol groups compared to the PND group.At 7 days postoperatively: compared with the PND group,serum IL-6 and hippocampus mitochondrial respiratory chain complexes I and IV levels were not significantly different(P > 0.05)and serum IL-10 levels were increased(P < 0.05)in the EA and Resveratrol groups;serum TNF-αlevels were decreased(P < 0.05)in the EA group;and serum TNF-α levels were not significantly different(P > 0.05)in the Resveratrol group(P > 0.05).3.Flow cytometry results showed that: At 3 and 7 days after surgery: compared with the Control group,hippocampus MMP was reduced in the PND group(P < 0.05).Compared with the PND group,hippocampus MMP were increased in the EA and Resveratrol groups(P < 0.05).4.The results of q PCR and WB experiments showed that: At 3 and 7 days after surgery: compared with Control group,Sirt1 protein and mRNA expression levels were decreased(P < 0.05),and NF-κB p65 protein and mRNA expression levels were increased(P < 0.05)in hippocampus tissue of rats in the PND group.Compared with PND group,the expression levels of Sirt1 protein and mRNA were increased(P < 0.05),and the expression levels of NF-κB p65 protein and mRNA were decreased(P < 0.05)in hippocampus of rats in EA and Resveratrol groups.Conclusion: Exploratory laparotomy can lead to postoperative cognitive impairment in aged rats,which was related to increased systemic inflammatory response and mitochondrial dysfunction of hippocampus cells.In addition,electroacupuncture and resveratrol can improve the learning and memory ability of PND rats for reasons that may be related to their modulation of the expression of the Sirt1/NF-κB signalling pathway,which in turn attenuated the systemic inflammatory response and mitochondrial dysfunction of hippocampus cells. |
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