Levodopa Improves Cognitive Function and the Deficits of Structural Synaptic Plasticity in Hippocampus Induced by Global Cerebral Ischemia/Reperfusion Injury in Rats

Volatile oil of Angelica sinensis Radix improves cognitive function by inhibiting miR-301a-3p targeting Ppp2ca in cerebral ischemia mice

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica Sinensis Radix (ASR) is a commonly used Chinese medicine known for its effects on tonifying blood, promoting blood circulation, and alleviating pain associated with menstrual regulation. Additionally, it has been used in the treatment of vascular cognitive impairment (VCI). The primary pharmacodynamic agent within ASR is volatile oil of Angelica Sinensis Radix (VOASR), which has demonstrated efficacy in combating cognitive impairment, although its mechanism remains unclear.

OBJECTIVE

This study aimed to elucidate the potential molecular mechanisms underlying VOASR's improvement of cognitive function in cerebral ischemic mice.

METHODS

A model of cerebral ischemic mice was established through unilateral common carotid artery occlusion (UCCAO) surgery, followed by intervention with VOASR. Cognitive function was assessed using the Morris water maze (MWM) test, while RT-qPCR was utilized to measure the differential expression of miR-301a-3p in the hippocampus. To evaluate cognitive function and hippocampal protein differences, wild-type mice and miR-301a-3p knockout mice were subjected to the MWM test and iTRAQ protein profiling. The relationship between miR-301a-3p and potential target genes was validated through a Dual-Luciferase Reporter experiment. RT-qPCR and Western blot were employed to determine the differential expression of Ppp2ca and synaptic plasticity-related proteins in the mouse hippocampus.

RESULTS

Intervention with VOASR significantly improved cognitive impairment in cerebral ischemic mice and reduced the expression of miR-301a-3p in the hippocampus. Our findings suggest that miR-301a-3p may regulate cognitive function by targeting Ppp2ca. Furthermore, VOASR intervention led to an increase in the expression of Ppp2ca and synaptic plasticity-related proteins.

CONCLUSION

Our study indicates that VOASR may be involved in regulating cognitive function by inhibiting miR-301a-3p, consequently increasing the expression of Ppp2ca and synaptic plasticity proteins. These results provide a new target and direction for the treatment of cognitive dysfunction.

IL-17A deficiency alleviates cerebral ischemia-reperfusion injury via activating ERK/MAPK pathway in hippocampal CA1 region

Cognitive impairment is a major complication of cerebral ischemia-reperfusion (CIR) injury and has an important impact on the quality of life of patients. However, the precise mechanisms underlying cognitive impairment after CIR injury remain elusive. In the current study, we investigated the role of interleukin 17 A (IL-17A) on CIR injury-induced cognitive impairment in wild-type and IL-17A knockout mice using RNA sequencing analysis, neurological assessments, Golgi-Cox staining, dendritic spine analysis, immunofluorescence assay, and western blot analysis. RNA sequencing identified 195 CIR-induced differentially expressed genes (83 upregulated and 112 downregulated), highlighting several enriched biological processes (negative regulation of phosphorylation, transcription regulator complex, and receptor ligand activity) and signaling pathways (mitogen-activated protein kinase [MAPK], tumor necrosis factor, and IL-17 signaling pathways). We also injected adeno-associated virus into the bilateral hippocampal CA1 regions of CIR mice to upregulate or downregulate cyclic AMP response element-binding protein. IL-17A knockout activated the extracellular signal-regulated kinase (ERK)/MAPK signaling pathway and further improved synaptic plasticity, structure, and function in CIR mice. Together, our findings suggest that IL-17A deficiency alleviates CIR injury by activating the ERK/MAPK signaling pathway and enhancing hippocampal synaptic plasticity.

Identification and characterization of biomarkers associated with endoplasmic reticulum protein processing in cerebral ischemia-reperfusion injury

Background

Cerebral ischemia (CI), ranking as the second leading global cause of death, is frequently treated by reestablishing blood flow and oxygenation. Paradoxically, this reperfusion can intensify tissue damage, leading to CI-reperfusion injury. This research sought to uncover biomarkers pertaining to protein processing in the endoplasmic reticulum (PER) during CI-reperfusion injury.

Methods

We utilized the Gene Expression Omnibus (GEO) dataset GSE163614 to discern differentially expressed genes (DEGs) and single out PER-related DEGs. The functions and pathways of these PER-related DEGs were identified via Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Core genes were pinpointed through protein-protein interaction (PPI) networks. Subsequent to this, genes with diagnostic relevance were distinguished using external validation datasets. A single-sample gene-set enrichment analysis (ssGSEA) was undertaken to pinpoint genes with strong associations to hypoxia and apoptosis, suggesting their potential roles as primary inducers of apoptosis in hypoxic conditions during ischemia-reperfusion injuries.

Results

Our study demonstrated that PER-related genes, specifically ADCY5, CAMK2A, PLCB1, NTRK2, and DLG4, were markedly down-regulated in models, exhibiting a robust association with hypoxia and apoptosis.

Conclusion

The data indicates that ADCY5, CAMK2A, PLCB1, NTRK2, and DLG4 could be pivotal genes responsible for triggering apoptosis in hypoxic environments during CI-reperfusion injury.

Voxel-based morphometry of grey matter structures in Parkinson's Disease with wearing-off

Our study aimed to investigate the grey matter (GM) changes using voxel-based morphometry (VBM) in Parkinson's disease (PD) patients with wearing-off (WO). 3D-T1-weighted imaging was performed on 48 PD patients without wearing-off (PD-nWO), 39 PD patients with wearing-off (PD-WO) and 47 age and sex-matched healthy controls (HCs). 3D structural images were analyzed by VBM procedure with Statistical Parametric Mapping (SPM12) to detect grey matter volume. Widespread areas of grey matter changes were found in patients among three groups (in bilateral frontal, temporal lobes, lingual gyrus, inferior occipital gyrus, right precuneus, right superior parietal gyrus and right cerebellum). Grey matter reductions were found in frontal lobe (right middle frontal gyrus, superior frontal gyrus and precentral gyrus), right parietal lobe (precuneus, superior parietal gyrus, postcentral gyrus), right temporal lobe (superior temporal gyrus, middle temporal gyrus), bilateral lingual gyrus and inferior occipital gyrus in PD-WO group compared with the PD-nWO group. Our results suggesting that wearing-off may be associated with grey matter atrophy in the cortical areas. These findings may aid in a better understanding of the brain degeneration process in PD with wearing-off.

Anti-inflammatory, anti-apoptotic, and neuroprotective potentials of anethole in Parkinson's disease-like motor and non-motor symptoms induced by rotenone in rats

Parkinson's disease (PD) is a complex neurological disorder characterized by a combination of motor and non-motor symptoms (NMS). Antioxidant and anti-inflammatory compounds are considered a potential therapeutic strategy against PD. The present study examined the neuroprotective effects of anethole as a potent antioxidant and anti-inflammatory agent against motor and non-motor deficits induced by rotenone toxicity. Rats were treated with anethole (62.5, 125, and 250 mg/kg, i.g) concomitantly with rotenone (2 mg/kg, s.c) for 5 weeks. After the treatment, behavioral tests were performed to evaluate motor function and depression-/anxiety-like behaviors. After the behavioral tests, rats were decapitated and brains were removed for histological analysis. Striatum samples were also isolated for neurochemical, and molecular analysis. Our data showed that rotenone-induced motor deficit, anxiety-and depression-like behaviors were significantly improved in rats treated with anethole. Furthermore, anethole treatment reduced inflammatory cytokines tumor necrosis factor α (TNFα) and Interleukin 6 (IL-6), and increased anti-inflammatory cytokine IL-4 in the striatum of rotenone-induced PD rats. Western blot analysis showed that treatment with anethole markedly suppressed caspase-3 activation induced by rotenone. Moreover, histological examination of striatum showed an increase in the number of surviving neurons after treatment with anethole. Anethole also significantly enhanced the striatal levels of dopamine in rotenone-induced PD rats. In addition, treatment with L-Dopa as a positive control group had effects similar to those of anethole on histological, neurochemical, and molecular parameters in rotenone-induced parkinsonian rats. Our results suggested the neuroprotective effects of anethole through anti-inflammatory, anti-apoptotic, and antioxidant mechanisms against rotenone-induced toxicity in rats.

Effects of different doses of dopamine receptor agonist pramipexole on neurobehaviors and changes of mitochondrial membrane potentials in rats with global cerebral ischemia-reperfusion injury

OBJECTIVE

To explore the effects of different doses of dopamine receptor agonist pramipexole on neurobehaviors and changes of mitochondrial membrane potential in rats with global cerebral ischemia-reperfusion injury.

METHODS

A total of 75 SPF Sprague-Dawley male rats were randomly divided into sham group (n=20), model group (n=20), pramipexole administration group (n=35). The rat model of global cerebral ischemia-reperfusion injury was prepared by the modified Pulsinelli's four-vessel occlusion method. Pramipexole administration group was administered intraperitoneally in rats with global cerebral ischemia-reperfusion injury at different doses of pramipexole 0.25 mg/kg, 0.5 mg/kg, 1 mg/kg, 2 mg/kg, once a day for 14 consecutive days. Based on the results of modified neurological severity scores, open field test and morphology by Nissl's staining to determine the optimal dose of pramipexole. Mitochondrial membrane potential in the optimal dose of pramipexole administration group were measured by the JC-1 fluorescent probe staining method.

RESULTS

1. Different doses of pramipexole 0.25 mg/kg, 0.5 mg/kg, 1 mg/kg, and 2 mg/kg, were used as drug administration in rats with global cerebral ischemia-reperfusion injury for 14 consecutive days, and we found that all four doses of pramipexole could improve the modified neurological severity scores of rats with global cerebral ischemia-reperfusion injury to varying degrees, but only 0.5 mg/kg pramipexole at 1, 3, 7 and 14 days consistently reduced modified neurological severity scores and improved neurological function in rats with global cerebral ischemia-reperfusion injury. In the open-field test, only 0.5 mg/kg pramipexole increased the number of entries into the central zone, duration spent in the central zone, total distance travelled in the open field and average velocity, which improved the spontaneous activities and reduced anxiety and depression of rats with global cerebral ischemia-reperfusion injury. 2. Different doses of pramipexole 0.25 mg/kg, 0.5 mg/kg, 1 mg/kg, and 2 mg/kg for 14 consecutive days significantly increased the number of surviving neurons in the hippocampal CA1 subfield in rats with global cerebral ischemia-reperfusion injury to varying degrees. Based on these results, we tentatively found that 0.5 mg/kg pramipexole may be the optimal dose in all of the above. 3. We found that 0.5 mg/kg pramipexole significantly increased the mitochondrial membrane potential in rats after global cerebral ischemia-reperfusion injury.

CONCLUSION

Different doses of dopamine receptor agonist pramipexole improved neurological function of rats with global cerebral ischemia-reperfusion injury to varying degrees, and 0.5 mg/kg pramipexole may be the optimal dose in all of the above. Pramipexole may produce neuroprotective effects by protecting neurons in the hippocampus and improving the mitochondrial membrane potential after global cerebral ischemia-reperfusion injury.

Ro25-6981 alleviates neuronal damage and improves cognitive deficits by attenuating oxidative stress via the Nrf2/ARE pathway in ischemia/reperfusion rats

OBJECTIVES

Oxidative stress plays a crucial role in the initiation and progression of cerebral ischemia‒reperfusion injury (CIRI). Therefore, ameliorating oxidative damage is considered to be a beneficial strategy for the treatment of CIRI. NMDAR NR2B subunit antagonists have been reported to be beneficial for synaptic plasticity, neuropathic pain, epilepsy, and cerebral ischemia. However, it remains unclear whether the NR2B subunit antagonist Ro25-6981 has any effect on CIRI.

METHODS

In this study, the Morris water maze test and passive avoidance test were used to detect spatial learning and memory. Neuronal loss was measured by Nissl staining. The expression of NSE was assayed by immunohistochemistry. The activities of MDA, 8-OHdG, SOD, GSH-Px, GST and CAT were detected by assay kits. Real-time PCR was used to detect the mRNA levels of hippocampal SOD, GSH-Px and HO-1. Western blotting was used to measure the activation of the Nrf2/ARE pathway by Ro25-6981.

RESULTS

Ro25-6981 ameliorated cognitive deficits and neuronal damage induced by ischemia‒reperfusion (I/R). Neuronal injury was decreased and the expression of NSE was increased in the CA1 regions of the hippocampus of I/R rats after Ro25-6981 treatment. Moreover, Ro25-6981 alleviated the levels of MDA and 8-OHdG by elevating the activities of SOD, GSH-Px, GST and CAT. Meanwhile, the mRNA levels of SOD, GSH-Px and HO-1 were increased in I/R rats after Ro25-6981 treatment. Furthermore, Ro25-6981 promoted the translocation of Nrf2 to the nucleus, promoting the expression of the Nrf2 downstream genes HO-1 and NQO1.

CONCLUSION

The present study indicated that the improvement in the antioxidant properties of Ro25-6981 is mediated by the Nrf2/ARE pathway. This is the first study to demonstrate a favorable effect of Ro25-6981 on cognitive impairment in a CIRI rat model, rendering this NR2B subunit antagonist a promising agent for the treatment or prevention of CIRI.

Transcranial near-infrared laser improves postoperative neurocognitive disorder in aged mice via SIRT3/AMPK/Nrf2 pathway

Background

Postoperative neurocognitive disorder (PND) is a common central nervous system (CNS) complication that might increase the morbidity and mortality of elderly patients after anesthesia/surgery. Neuroinflammation, oxidative stress, and synaptic dysfunction are closely related to cognitive dysfunction, an important clinical feature of PND. Transcranial near-infrared laser (TNIL) is regarded as an effective treatment for cognitive-related diseases by improving mitochondrial function and alleviating neuroinflammation and oxidative stress damage.

Materials and methods

Aged male C57BL/6 mice underwent a carotid artery exposure procedure under isoflurane anesthesia. We treated PND-aged mice for three consecutive days (4 h post-operation, 1-laser) with 810 nm continuous wave (CW) laser 18 J/cm² at 120 mW/cm². The post-treatment evaluation included behavioral tests, RTq-PCR, immunofluorescence, and Western blot.

Results

The results demonstrated that TNIL improved PND and the levels of synaptic function-associated proteins such as post-synaptic density protein 95 (PSD95), synaptophysin (SYP), and brain-derived neurotrophic factor (BDNF). Besides, neuroinflammatory cytokine levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β as well as microglia activation and oxidative stress damage were attenuated after TNIL treatment in aged mice with PND. Further investigation suggested that TNIL relieved oxidative stress response by activating the SIRT3/AMPK/Nrf2 pathway.

Conclusion

Transcranial near-infrared laser improved cognitive impairment in aged mice with PND, which may be a promising therapeutic for PND.

Frequent and Recent Non-fatal Strangulation/Choking During Sex and Its Association With fMRI Activation During Working Memory Tasks

Being strangled, or “choked,” by a sexual partner has emerged as a prevalent, often wanted and consensual sexual behavior among adolescent and young adult women, yet the neurological consequences of repeated exposure to this behavior are unknown. The objective of the study was to examine the association between a history of repeated, recent choking/strangling episodes during sex and fMRI activation during working memory tasks in young adult women. This case-control study involved young adult women (18–30 years old) at a large, public university, and consisted of two study groups: a choking group consisting of participants who were recently and frequently choked/strangled during sex by a partner (≥4 times in the past 30 days) and a choking-naïve (control) group who had never been choked/strangled during sex. Participants completed two variations of the N-back (0-back, 1-back, and 2-back) working memory task during functional magnetic resonance imaging (fMRI): verbal and visual N-back tasks. Data from 20 participants per group were available for analysis. Between-group differences for accuracy and reaction time were not significant for either variation of the N-back task. Significant differences in fMRI activation patterns were detected between the choking and the choking-naïve groups for the three contrasts of interest (1-back > 0-back, 2-back > 0-back, and 2-back > 1-back). The choking group exhibited increased activation in multiple clusters relative to the choking-naïve group for the contrasts between the 1-back and 2-back conditions compared to the 0-back conditions (e.g., superior frontal gyrus, corpus callosum). However, the choking-naïve group exhibited increased activation relative to the choking group in several clusters for the 2-back > 1 back contrast (e.g., splenium, middle frontal gyrus). These data indicate that recent, frequent exposure to partnered sexual strangulation is associated with different neural activation patterns during verbal and visual working memory tasks compared to controls, suggesting that being choked/strangled during sex may modify the allocation of neural resources at increasing levels of cognitive load. Further investigation into the neurologic effects of this sexual behavior is warranted, given the prevalence of sexual choking among adolescent and young adult women.

Neuroprotective effects of alisol A 24-acetate on cerebral ischaemia-reperfusion injury are mediated by regulating the PI3K/AKT pathway

BACKGROUND

Neuroinflammation and apoptosis are involved in the pathogenesis of ischaemic stroke. Alisol A 24-acetate (24A) exerts a strong inhibitory effect on inflammation and cell apoptosis. The neuroprotective effect of 24A on global cerebral ischaemia/reperfusion (GCI/R) injury remains unclear.

METHODS

GCI/R mice were used to investigate the neuroprotective effect of 24A. Modified neurological deficit scores, Morris water maze and object recognition tests were used to evaluate behaviours. Metabolism in brain regions was detected using magnetic resonance spectroscopy (MRS), and changes in microglia, astrocytes and neurons were detected. Inflammation and apoptosis were measured.

RESULTS

The results showed that 24A suppressed neurological deficits scores and improved GCI/R induced cognitive dysfunction. It was also observed that 24A could alleviate neuroinflammation, which manifested as 24A inhibited microglia and astrocytes proliferation, downregulated the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and inducible nitric oxide synthase (iNOS) in the GCI/R mice brain. The apoptosis of neurons reduced, and dendritic spines of hippocampal neurons increased in the presence of 24A. In addition, 24A could up-regulate the expression of phosphorylated phosphoinositide 3-kinases (p-PI3K) and phosphorylated protein kinase B (p-AKT) in GCI/R mice brain, and all the morphological, neurological, and biochemical changes of 24A treatment were abolished by the application of PI3K/AKT pathway inhibitor LY294002.

CONCLUSIONS

Taken together, our study indicated that 24A alleviated GCI/R injury by inhibiting neuroinflammation and apoptosis through the regulation of the PI3K/AKT pathway.

Clemastine Ameliorates Perioperative Neurocognitive Disorder in Aged Mice Caused by Anesthesia and Surgery

Perioperative neurocognitive disorder (PND) leads to progressive deterioration of cognitive function, especially in aged patients. Demyelination is closely associated with cognitive dysfunction. However, the relationship between PND and demyelination remains unclear. Here we showed that demyelination was related to the pathogenesis of PND. Clemastine, an antihistamine with potency in remyelination, was predicted to have a potential therapeutic effect on PND by next-generation sequencing and bioinformatics in our previous study. In the present study, it was given at 10 mg/kg per day for 2 weeks to evaluate the effects on PND in aged mice. We found that clemastine ameliorated PND and reduced the expression levels of inflammatory factors such as tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β). Further investigation suggested clemastine increased the expression of oligodendrocyte transcription factor 2 (OLIG2) and myelin basic protein (MBP) to enhance remyelination by inhibiting the overactivation of the WNT/β-catenin pathway. At the same time, the expression of post-synaptic density protein 95 (PSD95, or DLG4), brain-derived neurotrophic factor (BDNF), synaptosomal-associated protein 25 (SNAP25) and neuronal nuclei (NEUN) were also improved. Our results suggested that clemastine might be a therapy for PND caused by anesthetic and surgical factors in aged patients.

Diffusion tensor imaging of the hippocampus reflects the severity of hippocampal injury induced by global cerebral ischemia/reperfusion injury

At present, predicting the severity of brain injury caused by global cerebral ischemia/reperfusion injury (GCI/RI) is a clinical problem. After such an injury, clinical indicators that can directly reflect neurological dysfunction are lacking. The change in hippocampal microstructure is the key to memory formation and consolidation. Diffusion tensor imaging is a highly sensitive tool for visualizing injury to hippocampal microstructure. Although hippocampal microstructure, brain-derived neurotrophic factor (BDNF), and tropomyosin-related kinase B (TrkB) levels are closely related to nerve injury and the repair process after GCI/RI, whether these indicators can reflect the severity of such hippocampal injury remains unknown. To address this issue, we established rat models of GCI/RI using the four-vessel occlusion method. Diffusion tensor imaging parameters, BDNF, and TrkB levels were correlated with modified neurological severity scores. The results revealed that after GCI/RI, while neurological function was not related to BDNF and TrkB levels, it was related to hippocampal fractional anisotropy. These findings suggest that hippocampal fractional anisotropy can reflect the severity of hippocampal injury after global GCI/RI. The study was approved by the Institutional Animal Care and Use Committee of Capital Medical University, China (approval No. AEEI-2015-139) on November 9, 2015.

Cannabidiol Confers Neuroprotection in Rats in a Model of Transient Global Cerebral Ischemia: Impact of Hippocampal Synaptic Neuroplasticity

Evidence for the clinical use of neuroprotective drugs for the treatment of cerebral ischemia (CI) is still greatly limited. Spatial/temporal disorientation and cognitive dysfunction are among the most prominent long-term sequelae of CI. Cannabidiol (CBD) is a non-psychotomimetic constituent of Cannabis sativa that exerts neuroprotective effects against experimental CI. The present study investigated possible neuroprotective mechanisms of action of CBD on spatial memory impairments that are caused by transient global cerebral ischemia (TGCI) in rats. Hippocampal synaptic plasticity is a fundamental mechanism of learning and memory. Thus, we also evaluated the impact of CBD on neuroplastic changes in the hippocampus after TGCI. Wistar rats were trained to learn an eight-arm aversive radial maze (AvRM) task and underwent either sham or TGCI surgery. The animals received vehicle or 10 mg/kg CBD (i.p.) 30 min before surgery, 3 h after surgery, and then once daily for 14 days. On days 7 and 14, we performed a retention memory test. Another group of rats that received the same pharmacological treatment was tested in the object location test (OLT). Brains were removed and processed to assess neuronal degeneration, synaptic protein levels, and dendritic remodeling in the hippocampus. Cannabidiol treatment attenuated ischemia-induced memory deficits. In rats that were subjected to TGCI, CBD attenuated hippocampal CA1 neurodegeneration and increased brain-derived neurotrophic factor levels. Additionally, CBD protected neurons against the deleterious effects of TGCI on dendritic spine number and the length of dendritic arborization. These results suggest that the neuroprotective effects of CBD against TGCI-induced memory impairments involve changes in synaptic plasticity in the hippocampus.