Electroacupuncture Alleviates Neuroinflammation by Inhibiting the HMGB1 Signaling Pathway in Rats with Sepsis-Associated Encephalopathy

Electroacupuncture suppresses neuronal ferroptosis to relieve chronic neuropathic pain

Growing evidence supports the analgesic efficacy of electroacupuncture (EA) in managing chronic neuropathic pain (NP) in both patients and NP models induced by peripheral nerve injury. However, the underlying mechanisms remain incompletely understood. Ferroptosis, a novel form of programmed cell death, has been found to be activated during NP development, while EA has shown potential in promoting neurological recovery following acute cerebral injury by targeting ferroptosis. In this study, to investigate the detailed mechanism underlying EA intervention on NP, male Sprague-Dawley rats with chronic constriction injury (CCI)-induced NP model received EA treatment at acupoints ST36 and GV20 for 14 days. Results demonstrated that EA effectively attenuated CCI-induced pain hypersensitivity and mitigated neuron damage and loss in the spinal cord of NP rats. Moreover, EA reversed the oxidative stress-mediated spinal ferroptosis phenotype by upregulating reduced expression of xCT, glutathione peroxidase 4 (GPX4), ferritin heavy chain (FTH1) and superoxide dismutase (SOD) levels, and downregulating increased expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), malondialdehyde levels and iron overload. Furthermore, EA increased the immunofluorescence co-staining of GPX4 in neurons cells of the spinal cord of CCI rats. Mechanistic analysis unveiled that the inhibition of antioxidant pathway of Nrf2 signalling via its specific inhibitor, ML385, significantly countered EA's protective effect against neuronal ferroptosis in NP rats while marginally diminishing its analgesic effect. These findings suggest that EA treatment at acupoints ST36 and GV20 may protect against NP by inhibiting neuronal ferroptosis in the spinal cord, partially through the activation of Nrf2 signalling.

Pasteurized akkermansia muciniphila improves irritable bowel syndrome-like symptoms and related behavioral disorders in mice

Gut - brain communications disorders in irritable bowel syndrome (IBS) are associated with intestinal microbiota composition, increased gut permeability, and psychosocial disturbances. Symptoms of IBS are difficult to medicate, and hence much research is being made into alternative approaches. This study assesses the potential of a treatment with pasteurized Akkermansia muciniphila for alleviating IBS-like symptoms in two mouse models of IBS with different etiologies. Two clinically relevant animal models were used to mimic IBS-like symptoms in C57BL6/J mice: the neonatal maternal separation (NMS) paradigm and the Citrobacter rodentium infection model. In both models, gut permeability, colonic sensitivity, fecal microbiota composition and colonic IL-22 expression were evaluated. The cognitive performance and emotional state of the animals were also assessed by several tests in the C. rodentium infection model. The neuromodulation ability of pasteurized A. muciniphila was assessed on primary neuronal cells from mice dorsal root ganglia using a ratiometric calcium imaging approach. The administration of pasteurized A. muciniphila significantly reduced colonic hypersensitivity in both IBS mouse models, accompanied by a reinforcement of the intestinal barrier function. Beneficial effects of pasteurized A. muciniphila treatment have also been observed on anxiety-like behavior and memory defects in the C. rodentium infection model. Finally, a neuroinhibitory effect exerted by pasteurized A. muciniphila was observed on neuronal cells stimulated with two algogenic substances such as capsaicin and inflammatory soup. Our findings demonstrate novel anti-hyperalgesic and neuroinhibitory properties of pasteurized A. muciniphila, which therefore may have beneficial effects in relieving pain and anxiety in subjects with IBS.

α5GABAA receptor: A potential therapeutic target for perioperative neurocognitive disorders, a review of preclinical studies

Perioperative neurocognitive disorders (PND) are a common complication in elderly patients following surgery, which not only prolongs the recovery period but also affects their future quality of life and imposes a significant burden on their family and society. Multiple factors, including aging, vulnerability, anesthetic drugs, cerebral oxygen desaturation, and severe pain, have been associated with PND. Unfortunately, no effective drug is currently available to prevent PND. α5 γ-aminobutyric acid subtype A (α5GABAA) receptors have been implicated in cognitive function modulation. Positive or negative allosteric modulators of α5GABAA receptors have been found to improve cognitive impairment under different conditions. Therefore, targeting α5GABAA receptors may represent a promising treatment strategy for PND. This review focuses on preclinical studies of α5GABAA receptors and the risk factors associated with PND, primarily including aging, anesthetics, and neuroinflammation. Specifically, positive allosteric modulators of α5GABAA receptors have improved cognitive function in aged experimental animals. In contrast, negative allosteric modulators of α5GABAA receptors have been found to facilitate cognitive recovery in aged or adult experimental animals undergoing anesthesia and surgery but not in aged experimental animals under anesthesia alone. The reasons for the discordant findings have yet to be elucidated. In preclinical studies, different strategies of drug administration, as well as various behavioral tests, may influence the stability of the results. These issues need to be carefully considered in future studies.

Electroacupuncture reduces cerebral ischemia-induced neuronal damage in the hippocampal CA1 region in rats by inhibiting HMGB1 and p-JNK overexpression

BACKGROUND

The cornu ammonis 1 (CA1) region of the hippocampus is a sensitive area that is susceptible to injury caused by cerebral ischemia. High-mobility group box 1 (HMGB1) and phosphorylated c-Jun N-terminal kinase (p-JNK) play important roles in mediating cerebral ischemic injury.

OBJECTIVE

To elucidate the mechanism through which electroacupuncture (EA) via the Baihui (GV20) and Zusanli (ST36) acupoints protects neurons.

METHODS

A rat model of permanent middle cerebral artery occlusion (pMCAO) was established. Sprague-Dawley rats were divided into four groups: sham-operated control, pMCAO control, EA, and sham-EA (SEA). In the EA and SEA groups, the GV20 and ST36 acupoints were selected for treatment. However, the SEA group was treated only by superficial pricking of the skin at the two acupoints without the application of electricity. Neurological function was assessed using the neurological deficit function score, and neuronal damage was detected through Nissl staining. HMGB1 and p-JNK expression was evaluated using immunohistochemical staining and western blot assays.

RESULTS

The behavioural experiments showed that the EA treatment improved the neurological deficits in the pMCAO rats. The Nissl staining results revealed that EA reduced neural tissue damage. The immunohistochemical staining and western blot results showed that EA inhibited HMGB1 and p-JNK overexpression. By contrast, none of these EA effects were observed in the SEA group.

CONCLUSION

EA may reduce ischemia-induced neuronal damage in the hippocampal CA1 region by inhibiting the overexpression of both HMGB1 and p-JNK.

Sesquiterpene nootkatone counteracted the melamine-induced neurotoxicity via repressing of oxidative stress, inflammatory, and apoptotic trajectories

Melamine (ML), a chemical substance of high nitrogen content, is used as a food adulterant. Former evidences implied that ML could induce a variety of toxic effects including neurotoxicity and cognitive impairment. Therefore, the aim of this study was to delineate the protective effect of the nootkatone (NK) against ML-induced neural adverse effects. Rats were orally pretreated with NK (5 and 10 mg/kg) prior to the oral administration of ML (700 mg/kg) for a period of 28 days. Our findings unveiled remarkable alleviating effect of NK on MK-induced neurobehavioral disturbance in open field test. Furthermore, NK lessened ML-caused increases in the acetylcholine esterase level in the brain tissue of exposed rats. NK also decreased the neural oxidative stress as represented by elevated levels of SOD, CAT, and GSH along with decreased MDA and NO levels. Upregulated mRNA expression levels of neural NRF-2 and HO-1 were noticed after NK administration. Remarkable anti-inflammatory impact was prominent by decreased neural IL-1β, and TNF-α along with downregulated NF-κB and TLR-4 gene expression levels in NK-treated rats. Noteworthily, pre-treatment with NK decreased the immune reaction of RAGE and HMGB-1 induced by oral ML exposure. Brain histological examination validated the obtained biochemical and molecular results. To sum up, these outcomes reveal that NK successfully alleviated the neural damage induced by ML via blocking of oxidative stress, and inflammatory signaling pathways. Consequently, our study may suggest NK as a new effective therapeutic supplement for treatment of ML-mediated neurotoxicity in rats via inhibition of HMGB-1-RAGE/TLR-4/NF-κB.

Electroacupuncture-modulated extracellular ATP levels in prefrontal cortex ameliorated depressive-like behavior of maternal separation rats

Maternal separation (MS) is a type of early-life stress that has been linked to neuropsychiatric disorders, especially depression. Increasing evidence indicates that the adenosine triphosphate (ATP) level in the prefrontal cortex (PFC) is involved in the pathophysiology of depression. To investigate the potential relationship between ATP in PFC and antidepressant effects of electroacupuncture (EA) treatment, we assessed genes involved in ATP biosynthesis as well as the extracellular ATP levels in a rat model exposed to neonatal MS. Our results demonstrated that reduced expression of ABCG2 (an ATP-binding cassette protein) and ATP levels in the PFC of depressive-like rats exposed to MS can be attenuated by EA stimulus at the Baihui (GV20) and Yintang (GV29) acupoints. Moreover, the antidepressant effect of EA treatment was blocked by administration of suramin, a broad purinergic P2 receptor antagonist. Together, these results suggested that electroacupuncture may be able to modulate extracellular ATP levels in the PFC of depressive-like MS rats, potentially contributing to its antidepressant effects.

Acute and long-term cognitive impairment following sepsis: mechanism and prevention

INTRODUCTION

Sepsis is a severe host response to infection, which induces both acute and long-term cognitive impairment. Despite its high incidence following sepsis, the underlying mechanisms remain elusive and effective treatments are not available clinically.

AREA COVERED

This review focuses on elucidating the pathological mechanisms underlying cognitive impairment following sepsis. Specifically, the authors discuss the role of systemic inflammation response, blood-brain barrier disruption, neuroinflammation, mitochondrial dysfunction, neuronal dysfunction, and Aβ accumulation and tau phosphorylation in cognitive impairment after sepsis. Additionally, they review current strategies to ameliorate cognitive impairment.

EXPERT OPINION

Potential interventions to reduce cognitive impairment after sepsis include earlier diagnosis and effective infection control, hemodynamic homeostasis, and adequate brain perfusion. Furthermore, interventions to reduce inflammatory response, reactive oxygen species, blood-brain barrier disruption, mitochondrial dysfunction, neuronal injury or death could be beneficial. Implementing strategies to minimize delirium, sleep disturbance, stress factors, and immobility are also recommended. Furthermore, avoiding neurotoxins and implementing early rehabilitation may also be important for preventing cognitive impairment after sepsis.

Electroacupuncture inhibits the expression of HMGB1/RAGE and alleviates injury to the primary motor cortex in rats with cerebral ischemia

Background

The high-mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE) signaling pathway holds promise as a potential therapeutic target for ischemic brain injury. The effects of FPS-ZM1 and electroacupuncture (EA) on activation of the HMGB1/RAGE signaling pathway after cerebral ischemia remain uncertain.

Methods

Middle cerebral artery occlusion (MCAO) model was established. Neurological function was assessed using Longa scores. Nissl staining was used to observe the morphology of neurons. The expression levels of HMGB1 and RAGE were assayed with immunofluorescence staining and western blot.

Results

The results showed that EA and FPS-ZM1 could reduce the neural function score and neurons cell injury in cerebral ischemia rats by inhibiting the expression of HMGB1 and RAGE in primary motor cortex (M1) region. In addition, EA combined with FPS-ZM1 had a better therapeutic effect.

Conclusions

The HMGB1/RAGE pathway could be activated after cerebral ischemia. Both EA and FPS-ZM1 improved neurological deficits and attenuated neuronal damage in rats. They had synergistic effects. These interventions were observed to mitigate brain damage by suppressing the activation of HMGB1/RAGE.