Neurochemical Research最新文献

Studies have found that electroacupuncture (EA) can improve the neurocognitive function of cerebral small vessel disease (CSVD), restore cerebral blood flow, and protect neurovascular units. The occurrence and development of cerebral microvascular disease is highly related to neurovascular unit injury. However, it is not clear whether EA plays a therapeutic role by restoring neurovascular unit injury. To explore the possible therapeutic mechanism of EA by analyzing its effect on CSVD neurovascular units in rats with CSVD. Adult male Sprague–Dawley rats (n = 36) were used for the experiment. The rat model of bilateral carotid artery occlusion (BCAO) was established by bilateral common carotid artery ligation. The treatment group was treated with 2/100 Hz and 2–4 V continuous wave EA every day for 7 days. The water maze test and new object recognition test were used to evaluate the memory and cognition of rats. Golgi staining was performed to evaluate the synaptic plasticity. Western blotting was used to evaluate the expression of synaptic-associated proteins PSD95 and synaptophysin and neurovascular unit-associated proteins VEGF, NeuN, GFAP, and claudin5. The expression of neurovascular unit associated proteins VEGF, NeuN and GFAP was further evaluated by immunofluorescence staining. EA intervention significantly reduced cognitive memory damage, restored neuronal synaptic plasticity, and reduced neurovascular unit damage. EA significantly shortened the latency in the water maze test (p < 0.01), increased the number of platform crossings (p < 0.01) and the mean speed (p < 0.01), and increased new object recognition index (p < 0.01). EA significantly increased the total length of neuronal dendrites (p < 0.01) and the dendrite spinous density (p < 0.01). EA increased the levels of PSD95, Synaptophysin, VEGF, NeuN, GFAP and Claudin5 in the EA + BCAO group, compared with the BCAO group (p < 0.01). EA could improve the neurological function in a rat model of cerebral small vessel disease, and its mechanism may be related to the protective effect of electroacupuncture on neurovascular units.

Chronic inflammatory pain and depression are highly comorbid, with nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated ferroptosis in hippocampal neurons strongly associated with the onset and progression of the comorbidity. Electroacupuncture (EA), widely used to treat pain and mood disorders, may ameliorate chronic inflammatory pain and depression comorbidity (CIPDC) by inhibiting Nrf2-mediated ferroptosis in hippocampal neurons, though its mechanism of action remains partially understood. In this study, we established the CIPDC model by administering a subcutaneous injection of complete Freund’s adjuvant (CFA) into the left hind paw. Evaluations of EA’s effects on pain thresholds and depressive behaviors in CIPDC rats included paw withdrawal mechanical threshold, paw withdrawal thermal latency, sucrose preference test, open field test, and forced swim test assessments. HE staining was performed to assess the pathological and morphological alterations in hippocampal neurons. FJB staining was utilized to evaluate neuronal degeneration, while transmission electron microscopy (TEM) was employed to examine ultrastructural changes in hippocampal neuronal mitochondria. Prussian blue staining was conducted to visualize ferrous ion deposition in the hippocampus, and the contents of ferrous ion (Fe²⁺), malondialdehyde (MDA), and glutathione (GSH) were measured using colorimetric assay kits. Western blotting (WB) was performed to determine the relative protein expression of Nrf2, FTH1, FTL, xCT, GPX4, ACSL4, LPCAT3, and LOX in the hippocampus. Additionally, the relative mRNA expression of FTH1, FTL, xCT, GPX4, ACSL4, LPCAT3, and LOX was analyzed by PCR. Flow cytometry was used to quantify ROS levels in the hippocampus, and immunofluorescence staining was applied to detect nuclear expression of Nrf2 as well as co-localization of GPX4 with the neuronal marker NeuN. Our results demonstrate that EA upregulates nuclear Nrf2 expression in hippocampal tissue, thereby alleviating iron metabolism dysregulation, enhancing antioxidant system activity, and reducing lipid peroxidation. This process inhibits ferroptosis in hippocampal neurons, promoting their repair and remodeling, and effectively treating CIPDC.

The increasing interest in the pro-apoptotic function of calpain-2 in the course of Huntington’s disease (HD) is attributed to the involvement of its substrate, cyclin-dependent kinase 5 (Cdk5), in neuronal death during neurodegeneration. Oxytocin has been demonstrated to suppress apoptosis in many neurodegenerative disorders. This research aimed to investigate the effect of oxytocin on several calpain 2-induced apoptogenic factors in 3-nitropropionic acid (3-NP) animal model of HD in rats. For 14 days, rats received 3-NP (10 mg/kg, i.p.), and oxytocin (160 µg/kg, i.p.) 1 h before 3-NP administration. Oxytocin reversed the detrimental effects of 3-NP on the striatum, which was evidenced by improvement of motor behavior, as well as histological picture and neurochemical balance. Oxytocin markedly reduced striatal calpain-2 and p25 Cdk5 protein expressions and increased the endogenous calpain inhibitor, calpastatin expression along with the pro-survival factor, myocyte-enhancer factor 2 (MEF-2) contents. Moreover, it suppressed striatal content of the pro-apoptotic biomarkers (BCl-2-associated X protein (Bax), tumor suppressor protein (p53), and caspase-3) and elevated striatal anti-apoptotic B-cell lymphoma/leukemia 2 (BCl-2) content. It repressed the release of mitochondrial cytochrome c and apoptosis-inducing factor (AIF) to hinder caspase-dependent and caspase-independent apoptotic neuronal death. Oxytocin could be a promising candidate for HD management by hampering both mitochondrial and non-mitochondrial apoptosis through inhibition of calpain-2/p25 Cdk5/MEF-2 pathway.

Epilepsy is a chronic neurological disorder characterized by recurrent seizures, approximately one-third of whom are resistant to current anti-seizure drugs (ASDs). Retigabine (RTG) is a potential treatment for treating drug-resistant epilepsy and KCNQ2-related developmental and epileptic encephalopathy (KCNQ2-DEE). However, its use is limited by side effects from high doses and long-term use. This study aims to evaluate the anticonvulsant efficacy of RTG in combination with (+)-borneol in mouse models of maximal electroshock seizure (MES) and 6-Hz (44-mA) seizure. The individual anti-seizure efficacy of RTG and (+)-borneol was evaluated in the MES and 6-Hz seizure models, then isobolographic analysis was conducted to assess their interactions. The plasma and brain concentrations of RTG were measured with and without (+)-borneol. Electrophysiological experiments using the patch-clamp technique investigated the interactions of (+)-borneol and RTG at the α1β3γ2L-GABAAR and KCNQ2 channels. Both RTG and (+)-borneol exhibited anticonvulsant activity in MES and 6-Hz seizure models. In the isobolographic analysis, the co-administration of RTG and (+)-borneol proved to be significantly more effective than predicted based on additive effects. The ED50mix was reduced by approximately 20 to 100-fold and 2 to 6-fold compared to the ED50add in the MES and 6-Hz models, respectively. The plasma and brain levels of RTG increased following co-administration with higher doses of (+)-borneol. Patch-clamp studies indicated that both RTG and (+)-borneol positively modulated α1β3γ2L-GABAAR currents and showed additive effects. However, (+)-borneol inhibited the KCNQ2 current at 100 µM and did not enhance RTG activation on KCNQ2 channels at this concentration. These results demonstrate that (+)-borneol enhances the antiseizure effects of RTG by both pharmacokinetic and pharmacodynamic interaction and this approach may be clinically effective for patients with intractable seizures or KCNQ2-DEE.

Autism spectrum disorder (ASD) involves a complex neurodevelopmental pathogenesis. A disintegrin and metalloproteinase 10 (ADAM10) plays a crucial role in embryonic brain development and neural network stability. This study aimed to investigate the influence of ADAM10 on excitation/inhibition (E/I) balance, autism-like behaviors, and learning and memory dysfunction in rats prenatally exposed to valproic acid (VPA) and determine potential intervention strategies. The VPA-exposed group exhibited increased levels of ADAM10 and secreted amyloid precursor protein-α (sAPPα). Moreover, overexpression of glutamate decarboxylase 1 and N-methyl-D-aspartate receptors was observed. High-performance liquid chromatography-mass spectrometry revealed elevated levels of glutamate, glutamine, and γ-aminobutyric acid, as well as an E/I imbalance in the VPA group. Additionally, narrower synaptic clefts as well as increased postsynaptic density and synaptic vesicles were observed. Remarkably, intraperitoneal administration of ADAM10 inhibitor during the critical period of synaptic development significantly improved ASD-like behavior and learning and memory function in VPA-exposed rats. This intervention effectively reduced abnormally high sAPPα levels in the prefrontal cortex and corrected abnormal E/I balance. Thus, inhibiting ADAM10 overexpression may improve the E/I imbalance, alleviate core symptoms of ASD, and improve learning and memory dysfunction. The use of ADAM10 inhibitor represents a potential therapeutic strategy for treating ASD patients with intellectual disabilities.

Parkinson's disease is a complex neurological ailment manifested by dopaminergic neurodegeneration in the substantia nigra of the brain. This study investigates the molecular tripartite interaction between Lewy bodies, amyloid beta, and tau protein in the pathogenesis of Parkinson's disease. Lewy bodies which have been found as the important pathological hallmark in the degenerative neurons of Parkinson’s patients, are mainly composed of α-synuclein. The accumulation of α-synuclein has been directly and indirectly linked to the severity and degree of progression of the disease. In addition, approximately 50% of Parkinson's disease cases are also described by hyperphosphorylation of tau protein indicating its significant involvement in the disease. The study further explains how α-synuclein, tau and amyloid beta can spread via cross-seeding mechanisms and accelerate each other's aggregation leading to neuronal death. Both GSK-3β and CDK5 are involved in phosphorylation which among other effects contributes to the misfolding of both α-synuclein and tau proteins that lead to neurodegeneration in Alzheimer’s disease. Several mediators, that contribute to mitochondrial damage through elevated oxidative stress pathology are clearly described. Because of the increase in the incidence of Parkinson's disease, as predicted to be 17 million when the study was being conducted, studying these pathological mechanisms is very important in trying to establish treatments. This work contributes a path to finding a multi-target treatment regimen to alleviate the burden of this devastating disease.

Memory impairment is one of the cognitive symptoms in Huntington’s disease (HD) which appears before motor dysfunction in patients. Various molecular mechanisms, including disruptions in neurotrophins levels, are involved in the occurrence of memory problems in HD. Alpha-pinene (APN), a member of the monoterpene family, exhibited beneficial effects in animal models of neurodegenerative disorders. As a result, this study assessed the impact of APN on memory in the 3-nitropropionic acid (3-NP) induced model of HD in rats. Male Wistar rats received saline, 3-NP to model HD, or APN (1, 5, or 10 mg/kg) plus 3-NP for 21 days to assess APN’s effects. Working and spatial memory were examined by the Y-maze and Morris-water-maze (MWM) tests. The mRNA levels of neurotrophins and their receptors in the brain cortex and hippocampus of the rats were quantitatively assessed through Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) analysis. The results showed that APN, at all three doses, significantly prevented the disease phenotype induced by 3-NP administration. In addition, APN treatment elevated the gene expression levels of BDNF, TrkA, TrkB, and CREB, while significantly decreasing P75 NTR showing a dose-dependent effect in the brain cortex and hippocampus, compared to the 3-NP group. These findings suggest that APN alleviates 3-NP-induced memory deficits by enhancing neurotrophins and their receptor levels in an animal model of HD.

Bupivacaine (BUP) is a commonly used local anesthetic, while SH-SY5Y cells are a human neuroblastoma cell line frequently employed in research on neurotoxicity and neuroprotective mechanisms. To assess the neurotoxic effects of BUP on SH-SY5Y cells and the role of threonine-serine protein kinase B (Akt) signaling in BUP-induced nerve injury. SH-SY5Y cells were divided into three groups: the control group (Control), BUP group, and BUP + SC79 group. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the level of reactive oxygen species (ROS) in cells was detected using the dihydroethidium fluorescence probe method, and changes in mitochondrial membrane potential were detected by flow cytometry, while BUP-induced apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The effects of BUP on Bax, Bcl-2, Caspase-3, Caspase-9, Akt and phosphorylated Akt (p-Akt) were analyzed by Western blot (WB). Compared with the control group, the BUP group and the BUP + SC79 group showed significantly reduced cell viability, significantly increased apoptosis, significantly elevated ROS levels, significantly decreased JC-1 polymer/monomer ratio, significantly increased protein levels of Bax, caspase-3, caspase-9, Akt, and p-Akt, and significantly decreased Bcl-2 protein levels (P < 0.05). However, compared with the BUP group, the BUP + SC79 group exhibited significantly increased cell viability (P = 0.022), significantly reduced apoptosis rate (P = 0.017), significantly decreased ROS levels (P = 0.015), significantly increased JC-1 polymer/monomer ratio (P = 0.024), significantly reduced protein levels of Bax, caspase-3, caspase-9, Akt, and p-Akt (P = 0.033, 0.028, 0.030, 0.035, and 0.005, respectively), and significantly increased Bcl-2 protein levels (P = 0.024). BUP can reduce the viability of SH-SY5Y cells and promote apoptosis, which may be related to its inhibitory effect on Akt protein activity.

Bay k-8644, an activator of L-type voltage-gated calcium channels, induces self-injurious behaviors in mice. Although previous studies using animal models have suggested the possible implications of neuroinflammation in self-injurious behaviors, this has not yet been elucidated in the context of Bay k-8644-induced self-injurious behaviors. In this study, Bay k-8644 (50 µg, i.c.v.)-induced self-injurious behaviors were accompanied by increased expression of endothelin (ET)-1, platelet-activating factor (PAF) receptors, and Iba-1 in the striatum. Pretreatment with the ET receptor antagonist bosentan (10 mg/kg, i.p.), the PAF receptor antagonist ginkgolide B (10 mg/kg, i.p.), or the microglial activation inhibitor minocycline (40 mg/kg/day for 5 days, i.p.) significantly inhibited Bay k-8644-induced self-injurious behaviors and microglial activation in the striatum. Interestingly, bosentan also suppressed Bay k-8644-induced PAF receptor expression, indicating that ET-1 may act as an upstream modulator of the PAF signaling under these experimental conditions. Bay k-8644-induced ET-1 expression and consequent pro-inflammatory changes were reversed by the protein kinase C (PKC) inhibitor NPC-15,437 and the Ca²⁺/calmodulin-dependent kinase II (CaMKII) inhibitor KN-93. Moreover, Bay k-8644-induced self-injurious behaviors and microglial activation were significantly potentiated by exogenous ET-1 administration (10 pmol, i.c.v.) or by weak neuroinflammation in the striatum induced by systemic injection of low-dose lipopolysaccharide (LPS; 1 mg/kg, i.p.). Our results suggest that neuroinflammatory changes associated with ET-1/PAF signaling in the striatum contribute to Bay k-8644-induced self-injurious behaviors.

Parkinson’s Disease (PD) is a neurodegenerative disorder characterized by the pathological accumulation of alpha-synuclein (α-syn) in the neuronal cell bodies of the substantia nigra. The glymphatic system within the Central Nervous System (CNS) is responsible for clearing metabolic waste and abnormal proteins and its dysfunction may significantly contribute to the pathogenesis of PD. Our previous study showed that OAB-14, the novel small molecular compound, showed a great potential effect in APP/PS1 transgenic mice. Given the similarities in the pathogenesis of PD and Alzheimer’s disease (AD), it is pertinent to explore the therapeutic potential of OAB-14 in the context of PD. This study utilized a rotenone-induced PD mice model to evaluate the effects of oral administration of OAB-14, and its underlying mechanisms. Here we confirmed the neuroprotective effect and motor improvement of OAB-14 in rotenone-induced PD model mice. Our research has shown that OAB-14 is capable of enhancing the glymphatic system function by promoting the influx and efflux of the CSF tracers to the brain and deep cervical lymph nodes, respectively, to promote the clearance of α-syn. In addition, OAB-14 could down-regulate MyD88, NF-kB (Ser 536) phosphorylation, and TLR4 to reduce glial cell activation; and down-regulate cleaved-caspase1, NLRP3, ASC, IL-1β, IL-6, IL-18, TNF-α, and IL-10 to reduce the expression of inflammatory vesicles and pro-inflammatory factors, and to reduce neuronal oxidative stress. In summary, OAB-14 may promote the clearance of brain α-syn through the glial lymphatic system, inhibit the α-syn/TLR4/NF-κB/NLRP3 inflammatory pathway, and improve movement disorders.