Electroacupuncture pretreatment preserves telomerase reverse transcriptase function and alleviates postoperative cognitive dysfunction by suppressing oxidative stress and neuroinflammation in aged mice

Ginsenoside 1 mitigates postoperative cognitive dysfunction by enhancing microglial Aβ clearance through the endo-lysosomal pathway

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication in patients after surgery, especially in the elderly. The incidence of POCD not only impaired learning and memory, but also increased morbidity and mortality in patients. However, the exploration of therapeutic agents is limited. Ginsenoside 1 (Rg1) is one of the main compounds of ginseng, which exhibits bioactive and neuroprotective efficiency. In the present study, we aimed to investigate the effects of Rg1 on POCD.

METHODS

The POCD model was established by performing aseptic laparotomy surgery under anesthesia in 18-month mice. The cognition and anxiety of mice were assessed with MWM, OFT, and NOR tests. An in vitro model was performed on BV2 microglial cells. RNA sequencing, Western blotting, electrophysiology, Golgi staining, engulfment, and immunofluorescence analysis were performed.

RESULTS

Our results showed that Rg1 effectively alleviated the cognitive dysfuncion and anxiety of POCD mice. Transcriptomic sequencing data in microglia indicated that Rg1 mainly affects endosomes and lysosomes. By upregulating Rab7 and TFEB expression, Rg1 promoted microglial engulfment of Aβ through the endo-lysosomal pathway. Additionally, Rg1 reduced inflammatory levels, increased synaptic plasticity, and mitigated neuronal damage caused by Aβ. Moreover, the effects of Rg1 on TFEB depended on MEK/ERK signaling, while activation of MEK reversed Rg1's protective effects.

CONCLUSIONS

In conclusion, our study demonstrates that Rg1 can effectively ameliorate cognitive and synaptic deficit by enhancing microglial Aβ clearance through the endo-lysosomal pathway in aged POCD mice, which provides a potential strategy for the prevention of POCD.

Electroacupuncture Ameliorates Neuronal Damage and Neurological Deficits after Cerebral Ischemia-Reperfusion Injury via Restoring Telomerase Reverse Transcriptase

The purpose of this study is to identify the therapeutic effect of electroacupuncture (EA) on cerebral ischemia-reperfusion (I/R) injury, and to clarify the regulatory mechanism related to telomerase reverse transcriptase (TERT)-mediated telomerase activity. A Middle cerebral artery occlusion/reperfusion (MCAO/R) animal model was constructed and rats were treated by EA invention at the Baihui (GV20) and Fengchi (GB20) acupoints. Neurological deficits were assessed via rotarod test and Morris water maze test. 2,3,5-Triphenyltertrazolium chloride (TTC) staining was performed to evaluate infarct volume. Histological changes were observed under H&E staining and Nissl staining. TERT expression was examined using qRT-PCR and western blot. Telomerase activity was assessed with TRAP method. Neuron apoptosis and senescence were assessed by TUNEL and immunofluorescence assays. Inflammatory cytokines and oxidative stress-indicators were examined using commercial kits. EA intervention at both GV20 and GB20 acupoints reduced infarct volumes (2.48 ± 1.89 vs. 29.56 ± 2.55), elevated the telomerase activity (0.84 ± 0.08 vs. 0.34 ± 0.09), and upregulated the levels of total TERT protein (0.61 ± 0.09 vs. 0.21 ± 0.05) and mitochondrial TERT (Mito-TERT; 0.54 ± 0.03 vs. 0.27 ± 0.03) in hippocampus tissues of MCAO/R rats. EA intervention attenuated motor dysfunction (112.00 ± 6.69 vs. 30.02 ± 2.60) and improved spatial learning (23.87 ± 1.90 vs. 16.23 ± 1.45) and memory ability (8.38 ± 1.06 vs. 4.13 ± 1.13) of rats with cerebral I/R injury. In addition, EA intervention significantly attenuated histopathological changes of injured neurons, mitigated neuron apoptosis (32.27 ± 5.52 vs. 65.83 ± 4.31) and senescence in MCAO/R rats, as well as inhibited excessive production of inflammatory cytokines and attenuated oxidative stress. However, the above therapeutic efficiency of EA intervention in MCAO/R rats was partly eliminated by TERT knockdown. EA intervention at GB20 and GV20 acupoints exerted a protective role in cerebral I/R injury partly through restoring TERT function, implying the clinical potential of EA treatment in the treatment of ischemic stroke.

Electroacupuncture alleviates motor dysfunction after intracerebral hemorrhage via the PPARγ-EAAT2 pathway

Nowadays, intracerebral hemorrhage (ICH) is the main cause of death and disability, and motor impairment is a common sequel to ICH. Electroacupuncture (EA) has been widely used for functional recovery after ICH. However, its role and associated regulatory mechanisms in rehabilitation after ICH remain poorly understood. This study investigated whether EA can have a neuroprotective effect in motor function after ICH by inhibiting glutamate-mediated excitotoxicity on the primary motor cortex. The model was established using autologous tail artery blood, followed by administration of EA at Quchi (LI11) and Zusanli (ST36) for 3 or 7 consecutive days. The rats' behavior was examined by modified neurological severity score (mNSS) and open-field test (OFT). Nissl staining, immunofluorescence detection, and transmission electron microscopy were used to observe the degree of neuron damage. The level of the cortical glutamate was detected by the ELISA. Peroxisome proliferator-activated receptor gamma (PPARγ) expression was detected by immunohistochemistry and western blot. The protein and mRNA expression of excitatory amino acid transporter 2 (EAAT2) was detected by western blot and quantitative real-time PCR. Our data demonstrated that EA significantly reduces glutamate levels, alleviates neuronal damage, and promotes motor function recovery in rats after ICH. In addition, EA upregulates PPARγ and EAAT2 expression. However, the protective effect of EA on motor function and EAAT2 expression are partially abolished by T0070907, an antagonist of PPARγ. EA at LI11 and ST36 improved glutamate excitotoxicity and promoted motor function recovery after ICH by activating the PPARγ-EAAT2 pathway and reducing the glutamate level.

Electroacupuncture Ameliorates Postoperative Cognitive Dysfunction and Oxidative Stress via the SIRT1/FOXO1 Autophagy Pathway: An Animal Study

Postoperative cognitive dysfunction (POCD) is common in older adult patients and affects their prognosis. Studies suggested that autophagy and oxidative stress are key factors in the pathogenesis of POCD. This study aimed to determine whether electroacupuncture (EA) pre-treatment improves POCD in aged rats and the underlying mechanisms. We established a model of POCD by using propofol anaesthesia and caesarean section in aged mice and assessed whether electroacupuncture at the Baihui and Neiguan points modulates autophagy and oxidative stress involved in the pathological process of POCD. The Morris water maze test assessed postoperative cognitive function. Oxidative stress was assessed using flow cytometry and enzyme-linked immunosorbent assay (ELISA) to determine the levels of superoxide dismutase (SOD), reactive oxygen species (ROS) and malondialdehyde (MDA). Transmission electron microscopy was used to observe the ultrastructure of the hippocampal cord neurons. In addition, protein blotting and quantitative real-time polymerase chain reaction (PCR) assays were performed to assess SIRT1, FOXO1, and autophagy markers at both the protein and mRNA levels. The results showed that anaesthesia/surgery significantly impaired cognitive performance, increased oxidative stress, decreased autophagy in the hippocampus, damaged hippocampal neurones and disrupted the mitochondrial structure in aged rats. EA pre-treatment improved cognitive function, restored neuronal and mitochondrial function, increased Beclin-1 and SIRT1 levels and attenuated oxidative damage and autophagy dysfunction in POCD rats. In conclusion, EA pre-treatment improved POCD in aged rats, and this mechanism may be related to the enhancement of autophagy and the inhibition of oxidative stress through SIRT1/FOXO1 signalling.

Electroacupuncture regulates ferroptosis to improve postoperative cognitive dysfunction in mice through mediating GRX1/GSK-3β/Nrf2 axis

BACKGROUND

The incidence of postoperative cognitive dysfunction (POCD) is higher happening in the elderly. It has been reported electroacupuncture (EA) was beneficial to the treatment of POCD, but its specific regulatory mechanism is still unclear.

METHODS

Through partial hepatectomy in mice, POCD model of mice was established. Baihui acupoint (GV20) was selected for targeted point of EA therapy. Morris water maze (MWM) was applied to evaluate cognitive impairment of mice. HE staining was used to examine cell arrangement and cell morphology in hippocampus of mice. RT-qPCR, western blot and IHC were employed to detect abundance of genes and proteins. MDA, GSH and iron levels was measured by some commercial kits.

RESULTS

Our findings revealed that partial hepatectomy surgery impaired learning and memory ability of mice, promoted ferroptosis. inhibited GRX1 and inactivated GSK-3β/Nrf2 pathway. However, EA therapy abolished these effects. In addition, GRX1 silencing and erastin abolished EA-mediated alterations of improving POCD in mice.

CONCLUSION

EA suppressed ferroptosis by regulating GRX1/GSK-3β/Nrf2 pathway to improve postoperative cognitive dysfunction of POCD mice.

IL-12p70 Induces Neuroprotection via the PI3K-AKT-BCL2 Axis to Mediate the Therapeutic Effect of Electroacupuncture on Postoperative Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD), a postsurgical decline in cognitive function, primarily affects older adults and worsens their prognosis. Although elevated interleukin-12p70 (IL-12p70) is closely correlated with slower cognitive decline in older adults, its role in POCD remains unclear. Here, IL-12p70 is identified as a significant mediator of therapeutic effect of electroacupuncture (EA) on POCD. EA at acupoints ST36, GV20, and GV24 significantly enhanced cognitive behaviors of POCD mice. IL-12p70, downregulated in POCD mice but rescued by EA treatment, is the cytokine closely associated with EA's therapeutic effect. Clinically, IL-12p70 is downregulated in older adults' serum post-surgery. Furthermore, IL-12p70 exerts a potent neuroprotective effect in both neuronal cell lines and primary hippocampal neurons. The PI3K-AKT-BCL2 axis enriched by in silico analysis is validated as the signaling mechanism underlying IL-12p70-induced neuroprotection. In vivo, beneficial effects of EA treatment on the activation of PI3K-AKT-BCL2 axis and POCD are reproduced by IL-12p70 administration but attenuated by IL-12p70 knockdown. The findings reveal a novel mechanism underlying the therapeutic effect of EA on POCD, demonstrating that IL-12p70 exerts a neuroprotective effect by activating PI3K-AKT-BCL2 axis in hippocampal neurons. The newly-discovered function and mechanism of IL-12p70 highlight its potential in treating cognitive disorders.

Electroacupuncture Pretreatment Reduces Ischemic Brain Injury by Inhibiting the Lactate Production and Its Derived Protein Lactylation Formation

AIM

Given that electroacupuncture (EA) pretreatment inhibits lactate production and lactate-derived lysine lactation (Kla) aggravates ischemic brain injury, we aimed to investigate whether the formation of Kla protein is involved in EA pretreatment to alleviate ischemic brain injury.

METHODS

EA was performed on the Baihui acupoint (GV20) of male C57BL/6J mice before receiving the permanent middle cerebral artery occlusion (pMCAO) surgery. Western blot and immunofluorescent staining were used to observe neuronal survival, astrocyte activation, and protein Kla levels, and the lactate levels in ischemic brains were assayed with a commercial kit. TTC staining and neurological function scores are performed to evaluate the brain damage in mice.

RESULTS

We found that the increased lactate content and protein Kla levels were significantly decreased in ischemic brain tissue of mice after receiving EA pretreatment, and accompanied by the reduction of astrocyte activation and neuronal injury and death. Meantime, we found that EA pretreatment was effective in reversing the worsening of ischemic brain injury caused by lactate supplementation. However, EA pretreatment did not further reduce the lactate content and protein Kla levels and ameliorate brain injury in ischemic stroke mice after inhibition of glycolysis.

CONCLUSION

Our study reveals that EA pretreatment reduced ischemic brain damage by inhibiting lactate production and its derived protein Kla formation in mice with ischemic stroke.

Unraveling the role and mechanism of mitochondria in postoperative cognitive dysfunction: a narrative review

Postoperative cognitive dysfunction (POCD) is a frequent neurological complication encountered during the perioperative period with unclear mechanisms and no effective treatments. Recent research into the pathogenesis of POCD has primarily focused on neuroinflammation, oxidative stress, changes in neural synaptic plasticity and neurotransmitter imbalances. Given the high-energy metabolism of neurons and their critical dependency on mitochondria, mitochondrial dysfunction directly affects neuronal function. Additionally, as the primary organelles generating reactive oxygen species, mitochondria are closely linked to the pathological processes of neuroinflammation. Surgery and anesthesia can induce mitochondrial dysfunction, increase mitochondrial oxidative stress, and disrupt mitochondrial quality-control mechanisms via various pathways, hence serving as key initiators of the POCD pathological process. We conducted a review on the role and potential mechanisms of mitochondria in postoperative cognitive dysfunction by consulting relevant literature from the PubMed and EMBASE databases spanning the past 25 years. Our findings indicate that surgery and anesthesia can inhibit mitochondrial respiration, thereby reducing ATP production, decreasing mitochondrial membrane potential, promoting mitochondrial fission, inducing mitochondrial calcium buffering abnormalities and iron accumulation, inhibiting mitophagy, and increasing mitochondrial oxidative stress. Mitochondrial dysfunction and damage can ultimately lead to impaired neuronal function, abnormal synaptic transmission, impaired synthesis and release of neurotransmitters, and even neuronal death, resulting in cognitive dysfunction. Targeted mitochondrial therapies have shown positive outcomes, holding promise as a novel treatment for POCD.

Keap1-independent GSK-3β/Nrf2 signaling mediates electroacupuncture inhibition of oxidative stress to induce cerebral ischemia-reperfusion tolerance

PURPOSE

Cerebral ischemia-reperfusion (CIR) injury is a devastating consequence of stroke characterized by oxidative stress-induced neuronal damage. Electroacupuncture (EA) has emerged as a potential therapeutic intervention for ischemic stroke, but its underlying mechanisms remain incompletely understood. This study aimed to elucidate whether EA exerts anti-oxidative stress effects against CIR injury by modulating the GSK-3β/Nrf2 pathway.

METHODS

CIR mouse models were established using the suture-occluded method and underwent EA pretreatment. Cognitive and neurologic function, cerebral infarct volume, and neuronal damage were assessed in mice. Oxidative stress levels and the expression of components of the GSK-3β/Nrf2 pathway in the cerebral cortex were measured. The regulatory effect of GSK-3β on Nrf2 and its role in electroacupuncture to alleviate oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal injury were investigated by modulating GSK-3β expression in HT22 hippocampal neuronal cells and electroacupuncture serum intervention. Ultimately, Nrf2 knockout mice, GSK-3β knockout mice, and wild-type mice treated with TBHQ (an Nrf2 activator) were utilized for further validation.

RESULTS

EA pretreatment improved cognitive impairment and neuronal damage induced by CIR injury. Mechanistically, EA inhibited oxidative stress in the cerebral cortex, manifested by reduced levels of reactive oxygen species and malondialdehyde, along with increased superoxide dismutase activity. Furthermore, EA upregulated the expression of Nrf2 and its downstream antioxidant enzymes HO-1 and NQO1, while Keap1 expression remained unaffected. In vitro, GSK-3β overexpression inhibited the protective effects of EA serum on OGD/R-induced neuronal damage. In vivo, knockout of either Nrf2 or Gsk-3β genes abolished the neuroprotective effects of EA, and TBHQ exerted effects similar to EA, confirming the significant role of GSK-3β/Nrf2 in mediating EA antioxidative effects.

CONCLUSION

EA exerts antioxidative stress effects against CIR injury by activating the GSK-3β/Nrf2 signaling pathway, independent of Keap1 regulation.

Postoperative Electroacupuncture Boosts Cognitive Function Recovery after Laparotomy in Mice

Postoperative cognitive dysfunction (POCD) is a common complication that affects memory, executive function, and processing speed postoperatively. The pathogenesis of POCD is linked to excessive neuroinflammation and pre-existing Alzheimer's disease (AD) pathology. Previous studies have shown that acupuncture improves cognition in the early phase of POCD. However, POCD can last for longer periods (up to weeks and years). The long-term effects of acupuncture are unknown. In this study, we hypothesized that electroacupuncture (EA) could reduce inflammation and cognitive dysfunction induced by laparotomy over a longer period. We characterized the effects of postoperative EA on cognitive changes and investigated the underlying molecular mechanisms in mice. Laparotomy was performed in 3-month-old mice followed by daily EA treatment for 2 weeks. Our data indicated that laparotomy induced prolonged impairment in memory and executive functions, which were mitigated by postoperative EA. EA also reduced tau phosphorylation and suppressed the activation of tau-related kinases and glia, with effects comparable to ibuprofen. These findings demonstrate the beneficial effects of EA in a mouse model of POCD, suggesting that EA's ability to suppress neuroinflammation may contribute to its protective effects. In conclusion, EA may be a viable non-pharmacological intervention for managing POCD in different phases of the medical condition.

Updated insights into the NLRP3 inflammasome in postoperative cognitive dysfunction: emerging mechanisms and treatments

Postoperative cognitive dysfunction (POCD) poses a significant threat to patients undergoing anesthesia and surgery, particularly elderly patients. It is characterized by diminished cognitive functions post surgery, such as impaired memory and decreased concentration. The potential risk factors for POCD include age, surgical trauma, anesthetic type, and overall health condition; however, the precise mechanisms underlying POCD remain elusive. Recent studies suggest that neuroinflammation might be a primary pathogenic factor. NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes are implicated in exacerbating POCD by promoting the release of inflammatory factors and proteins that initiate pyroptosis, further influencing the disease process. The regulation of NLRP3 inflammasome activity, including its activation and degradation, is tightly controlled through multiple pathways and mechanisms. In addition, autophagy, a protective mechanism, regulates the NLRP3 inflammasome to control the progression of POCD. This review reviews recent findings on the role of the NLRP3 inflammasome in POCD pathogenesis and discusses therapeutic strategies aimed at reducing NLRP3 sources, inhibiting cellular pyroptosis, and enhancing autophagy.

Effects of electroacupuncture on postoperative cognitive dysfunction and its underlying mechanisms: a literature review of rodent studies

With the aging of the population, the health of the elderly has become increasingly important. Postoperative cognitive dysfunction (POCD) is a common neurological complication in elderly patients following general anesthesia or surgery. It is characterized by cognitive decline that may persist for weeks, months, or even longer. Electroacupuncture (EA), a novel therapy that combines physical nerve stimulation with acupuncture treatment from traditional Chinese medicine, holds potential as a therapeutic intervention for preventing and treating POCD, particularly in elderly patients. Although the beneficial effects of EA on POCD have been explored in preclinical and clinical studies, the reliability of EA is limited by methodological shortcomings, and the underlying mechanisms remain largely unexplored. Therefore, we have synthesized existing evidence and proposed potential biological mechanisms underlying the effects of EA on neuroinflammation, oxidative stress, autophagy, the microbiota-gut-brain axis, and epigenetic modification. This review summarizes recent advances in EA and POCD, provides a theoretical foundation, explores potential molecular mechanisms for the prevention and treatment of POCD, and offers a basis for conducting relevant clinical trials.

Electroacupuncture pretreatment preserves telomerase reverse transcriptase function and alleviates postoperative cognitive dysfunction by suppressing oxidative stress and neuroinflammation in aged mice

BACKGROUND

Elderly patients often exhibit postoperative cognitive dysfunction (POCD), a postsurgical decline in memory and executive function. Oxidative stress and neuroinflammation, both pathological characteristics of the aged brain, contribute to this decline. This study posits that electroacupuncture (EA) stimulation, an effective antioxidant and anti-inflammatory modality, may enhance telomerase reverse transcriptase (TERT) function, the catalytic subunit of telomerase known for its protective properties against cellular senescence and oxidative damage, to alleviate POCD in aged mice.

METHODS

The animal POCD model was created by subjecting aged mice to abdominal surgery, followed by EA pretreatment at the Baihui acupoint (GV20). Postoperative cognitive function was gauged using the Morris water maze (MWM) test. Hippocampal TERT mRNA levels and telomerase activity were determined through qPCR and a Telomerase PCR ELISA kit, respectively. Oxidative stress was assessed through superoxide dismutase (SOD), reactive oxygen species (ROS), and malondialdehyde (MDA) levels. Iba-1 immunostaining determined the quantity of hippocampal microglia. Additionally, western blotting assessed TERT, autophagy markers, and proinflammatory cytokines at the protein level.

RESULTS

Abdominal surgery in aged mice significantly decreased telomerase activity and TERT mRNA and protein levels, but increased oxidative stress and neuroinflammation and decreased autophagy in the hippocampus. EA-pretreated mice demonstrated improved postoperative cognitive performance, enhanced telomerase activity, increased TERT protein expression, improved TERT mitochondrial localization, and reduced oxidative damage, autophagy dysfunction, and neuroinflammation. The neuroprotective benefits of EA pretreatment were diminished following TERT knockdown.

CONCLUSIONS

Our findings underscore the significance of TERT function preservation in alleviating surgery-induced oxidative stress and neuroinflammation in aged mice. A novel neuroprotective mechanism of EA stimulation is highlighted, whereby modulation of TERT and telomerase activity reduces oxidative damage and neuroinflammation. Consequently, maintaining TERT function via EA treatment could serve as an effective strategy for managing POCD in elderly patients.