Blast-Induced Central Auditory Neurodegeneration Affects Tinnitus Development Regardless of Peripheral Cochlear Damage.

Blast exposure causes serious complications, the most common of which are ear-related symptoms such as hearing loss and tinnitus. The blast shock waves can cause neurodegeneration of the auditory pathway in the brainstem, as well as the cochlea, which is the primary receptor for hearing, leading to blast-induced tinnitus. However, it is still unclear which lesion is more dominant in triggering tinnitus, the peripheral cochlea or the brainstem lesion owing to the complex pathophysiology and the difficulty in objectively measuring tinnitus. Recently, gap detection tests have been developed and are potentially well-suited for determining the presence of tinnitus. In this study, we investigated whether the peripheral cochlea or the central nervous system has a dominant effect on the generation of tinnitus using a blast-exposed mouse model with or without earplugs, which prevent cochlear damage from a blast transmitted via the external auditory canal. The results showed that the earplug (+) group, in which the cochlea was neither physiologically nor histologically damaged, showed a similar extent of tinnitus behavior in a gap prepulse inhibition of acoustic startle reflex test as the earplug (-) group, in which the explosion caused a cochlear synaptic loss in the inner hair cells and demyelination of auditory neurons. In contrast, both excitatory synapses labeled with VGLUT-1 and inhibitory synapses labeled with GAD65 were reduced in the ventral cochlear nucleus, and demyelination in the medial nucleus of the trapezoid body was observed in both groups. These disruptions significantly correlated with the presence of tinnitus behavior regardless of cochlear damage. These results indicate that the lesion in the brainstem could be dominant to the cochlear lesion in the development of tinnitus following blast exposure.

The AMPK activator metformin improves recovery from demyelination by shifting oligodendrocyte bioenergetics and accelerating OPC differentiation.

Multiple Sclerosis (MS) is a chronic disease characterized by immune-mediated destruction of myelinating oligodendroglia in the central nervous system. Loss of myelin leads to neurological dysfunction and, if myelin repair fails, neurodegeneration of the denuded axons. Virtually all treatments for MS act by suppressing immune function, but do not alter myelin repair outcomes or long-term disability. Excitingly, the diabetes drug metformin, a potent activator of the cellular "energy sensor" AMPK complex, has recently been reported to enhance recovery from demyelination. In aged mice, metformin can restore responsiveness of oligodendrocyte progenitor cells (OPCs) to pro-differentiation cues, enhancing their ability to differentiate and thus repair myelin. However, metformin's influence on young oligodendroglia remains poorly understood. Here we investigated metformin's effect on the temporal dynamics of differentiation and metabolism in young, healthy oligodendroglia and in oligodendroglia following myelin damage in young adult mice. Our findings reveal that metformin accelerates early stages of myelin repair following cuprizone-induced myelin damage. Metformin treatment of both isolated OPCs and oligodendrocytes altered cellular bioenergetics, but in distinct ways, suppressing oxidative phosphorylation and enhancing glycolysis in OPCs, but enhancing oxidative phosphorylation and glycolysis in both immature and mature oligodendrocytes. In addition, metformin accelerated the differentiation of OPCs to oligodendrocytes in an AMPK-dependent manner that was also dependent on metformin's ability to modulate cell metabolism. In summary, metformin dramatically alters metabolism and accelerates oligodendroglial differentiation both in health and following myelin damage. This finding broadens our knowledge of metformin's potential to promote myelin repair in MS and in other diseases with myelin loss or altered myelination dynamics.

Comparison and effect of moxibustion and acupuncture on Nogo/NgR signaling pathway in rats with cerebral ischemia/reperfusion injury.

Background and aim: In China, acupuncture and moxibustion have been used effectively to treat various diseases for thousands of years. However, the evidence for a difference in the efficacies of moxibustion and acupuncture in cerebral infarction treatment is scarce. We aimed to compare the effects of acupuncture and moxibustion treatment on the Nogo/NgR signaling pathway in rats with cerebral ischemia/reperfusion (I/R) injury. Experimental procedure: Eighty male SD rats were randomly divided into five groups, based on treatment received: sham surgery (sham group), middle cerebral artery occlusion (MCAO, MCAO group), MCAO and NEP(1-40) inhibitor injection (MCAO + block group), MCAO and moxibustion (MCAO + moxi group), and MCAO and minimal acupuncture (MCAO + MA group). Neurological status was evaluated before treatment, and cerebral infarction volume (IV) and neurological function; Nogo-A, NgR, p75NTR, and LINGO-1 expressions; and NgR and LINGO-1 co-expression were assessed after treatment. Results and conclusion: After treatment, barring Nogo-A mRNA and protein expression in the MCAO + block group, the Longa score and IV significantly decreased; Nogo-A, NgR, p75NTR, and LINGO-1 mRNA and protein expressions as well as NgR and LINGO-1 co-expression significantly decreased in cerebral tissues; whereas the BWT score increased (P < 0.01) in the MCAO + moxi group, compared with the MCAO group. Except for NgR and LINGO-1 protein expressions, there were no significant differences in the abovementioned parameters between rats that underwent acupuncture and moxibustion. Acupuncture and moxibustion have similar effects on Nogo/NgR signaling pathway inhibition after cerebral infarction.

Curcumin's spice-infused therapeutic promise: disease severity alleviation in a mouse model of multiple sclerosis via modulation of immune responses.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune central nervous system (CNS) disorder indicated by demyelination, chronic inflammation, and neuronal destruction. Regional demyelination, inflammation responses, scar development, and various axonal damage are pathological characteristics of MS. Curcumin is a hydrophobic polyphenol extracted from the rhizome of the turmeric plant. In addition to anti-inflammatory effects, beneficial therapeutic effects such as antioxidant, anti-cancer and nerve protection have also been seen from this compound. The purpose of the current investigation was to provide light on the potential benefits of Curcumin in treating experimental autoimmune encephalomyelitis (EAE), the animal model of MS. METHODS AND RESULTS: in Female C57BL/6 mice were used to induce EAE through myelin oligodendroglial glycoprotein (MOG). Curcumin doses of 100 and 200 mg/kg were administered orally in the treatment groups starting on the first day of EAE induction. Brains and splenocytes were extracted from euthanized animals on day 25 following EAE induction. Demyelination and leukocyte infiltration, proliferation, cytokine, and gene expression profiles were assessed. Our findings demonstrate that both low and high doses of Curcumin decreased the progression of EAE. Histological analyses revealed low infiltration of leukocytes into the CNS. Curcumin therapy enhanced Th2 and Treg cell secretion of IL-4, IL-10, and TGF-ß although considerably decreasing IFN-γ and TNF-α. Curcumin-induced Th2 and Treg cell cytokine production and transcription factor gene expression (IL-13, GATA3, STAT6 and IL-35, CTLA4, Foxp3) and anti-inflammatory cytokines (IL-27, IL-33). CONCLUSION: Overall, these findings provide additional evidence that Curcumin can slow disease development and alleviate symptoms in EAE through stimulating Treg and Th2 cell polarization. They support Curcumin's potential therapeutic role in MS.

Lentinan alleviates sciatic nerve injury by promoting autophagy to remove myelin fragments.

Lentinan, a natural drug with wide-ranging pharmacological activities, can regulate autophagy-the process through which Schwann cells (SCs) eliminate myelin fragments after peripheral nerve injury (PNI). However, the effect of lentinan after PNI and the role of accelerated myelin debris removal via autophagy in this process are unclear. This study examined the effect of lentinan on rat sciatic nerve repair following crush injury and the underlying mechanisms. After the successful establishment of the sciatic nerve compression injury model, group-specific treatments were performed. The treatment group received 20 mg/kg lentinan via intraperitoneal injection, while the model group was treated with normal saline. The recovery in each group was then evaluated. Further, a rat SC line (RSC96) was cultured in medium with/without lentinan after supplementation with homogenous myelin fractions to evaluate the removal of myelin particles. Our results showed that lentinan promotes autophagic flux in vivo via the AMPK/mTOR signaling pathway, accelerates the clearance of myelin debris by SCs, and inhibits neuronal apoptosis, thereby promoting neurological recovery. Similarly, in vitro experiments showed that lentinan promotes the phagocytosis of myelin debris by SCs. In conclusion, our results suggest that lentinan primarily promotes nerve regeneration by accelerating the autophagic clearance of myelin debris in SCs, and this process is likely regulated by the AMPK/mTOR signaling pathway. Therefore, this study provides compelling evidence that lentinan may be a cost-effective and natural treatment agent for PNI.

Berberine promotes immunological outcomes and decreases neuroinflammation in the experimental model of multiple sclerosis through the expansion of Treg and Th2 cells.

INTRODUCTION: Among the most frequent demyelinating autoimmune disorders of the central nervous system (CNS) is multiple sclerosis. Experimental autoimmune encephalomyelitis (EAE) is used as an animal model of multiple sclerosis. Berberine is an alkaloid found in some medicinal plants with anti-inflammatory effects. METHODS: C57BL/6 female mice were used and divided into three groups: (1) The control group received PBS, (2) the low-dose treatment group received 10 mg/kg of berberine, and (3) The high-dose treatment group received 30 mg/kg of berberine. Myelin Oligodendrocyte Glycoprotein and complete Freund's adjuvant were subcutaneously administered to induce EAE. Mice were given intraperitoneal injections of pertussis toxin on the day of immunization and 2 days later. Histological studies showed low lymphocyte infiltration and demyelination of CNS in the treated groups. RESULTS: The clinical scores of the treatment group with low-dose berberine (T1: 2 ± 0.13) and high-dose berberine (T2: 1.5 ± 0.14) were significantly (p < .001) lower than the control group (CTRL: 4.5 ± 0.13). Treatment groups decreased pro-inflammatory cytokines (IFN-γ, TNF-α, interleukin [IL]-17) (p < .001) as well as increased anti-inflammatory cytokine expression (IL-4, IL-10, IL-27, IL-33, IL-35, TGF-ß) (p < .01) when compared to the CTRL group. Treatment groups with berberine reduced expression of the Th1 and Th17 cytokines and transcription factors (p < .001) and increased expression of transcription factors and Th2 and Treg cytokines (p < .01) in contrast to CTRL group. CONCLUSION: Berberine appears to have a protective effect on disease development and alleviating disease status in EAE, which appears to be due to the cell expansion and function of Treg and Th2 cells in addition to berberine's anti-inflammatory properties.

Effect of Hyperbaric oxygen on myelin injury and repair after hypoxic-ischemic brain damage in adult rat.

INTRODUCTION: Hypoxic-ischemic encephalopathy (HIE) is one of the leading causes of death and neurological disability with limited options for treatment in neonates, children and adults worldwide. The pathogenesis and treatment of white matter (WM) injury in adult patients with HIE remains largely elusive. METHODS: Sixty male Sprague-Dawley rats were randomly divided into control group, sham-operated group (HBO treatment 6 days after sham operation), and Hypoxia-ischemia (HI) induced brain damage group (receiving left carotid arteries ligation + hypoxia treatment), 1.5ATA hyperbaric oxygen group (HI + 1.5ATA HBOT) and 2.5ATA HBOT group (HI + 2.5ATA HBOT). All the rats were evaluated by water maze before operation, and 6 days after operation, and the function of learning and memory was evaluated; Demyelination in the hippocampus and prefrontal cortex was observed by Luxol fast blue staining (LFB) and MBP immunostaining; the number of Myelin Oligodendrocyte Glycoprotein (MOG),glial fibrillary acidic protein (GFAP), ionic calcium-binding adaptor (Iba-1) and NG2 positive cells in the hippocampus and prefrontal cortex were determined by immunofluorescence staining. The expression of interleukin-1ß (IL-1ß), IL-6 and tumor necrosis factor (TNF-α), Hypoxia Inducible Factor 1 Subunit Alpha (HIF1-α) and Superoxide dismutase (SOD) in brain and serum of rats were measured by Western Blot method and Enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with those in the normal control group and sham-operated group, in the HI group, the learning and memory abilities of rats were significantly decreased (P < 0.05), the intensity of LFB and MBP immunostaining in hippocampus and prefrontal cortex was significantly decreased (P < 0.05); the number of MOG positive oligodendrocytes (OLs) significantly decreased (P < 0.05), whereas the number of Iba-1, GFAP, NG2 positive microglias, astrocytes and oligodendrocyte precursors (OPCs) was increased (P < 0.05); the level of IL-1ß, IL-6, TNF-α and HIF-1a in brain and serum were significantly increased (P < 0.05), whereas SOD was significantly decreased in brain and increased in serum. Compared with those in the HI group, in both 1.5ATA and 2.5ATA HBOT group, the learning and memory abilities were significantly increased (P < 0.05); the intensity of LFB and MBP immunostaining in the hippocampus and prefrontal cortex was significantly increased (P < 0.05); the number of MOG positive OLs significantly increased (P < 0.05); the number of Iba-1, GFAP, NG2 positive microglias, astrocytes and OPCs was decreased (P < 0.05); the level of IL-1ß, IL-6, TNF-α and HIF-1a in brain and serum were significantly decreased (P < 0.05); the level of SOD was significantly increased in brain and decreased in serum. Morever, compared with those in the 1.5ATA group, 2.5ATA provided better treatment results (P < 0.05). CONCLUSION: In the present study, we demonstrated the mechanism of different pressure HBOT on HI induced brain injury from three levels: (1) On a tissue level, HBOT protects against HI induced myelin injury; (2) On a cellular level, HBOT attenuates HI-induced OL loss, suppresss the reactive activation of astrocyte and microglia, and may promote OPC to differentiate into OL; (3) On a molecular level, HBOT inhibites neuroinflammation, and balances oxidative damage and antioxidant capacity. Among the above effects, 2.5ATA HBOT is better than 1.5ATA HBOT. Ongoing research will continue to seek out the signalling pathways and molecules mechanisms on different pressure of HBOT-related myelin protection, and possibly expand suitable HBOT use in adult HIE clinically.

Evidence of An Association Between Cerebral Blood Flow and Microstructural Integrity in Normative Aging Using a Holistic MRI Approach.

BACKGROUND: Cerebral tissue integrity decline and cerebral blood flow (CBF) alteration are major aspects of motor and cognitive dysfunctions and neurodegeneration. However, little is known about the association between blood flow and brain microstructural integrity, especially in normal aging. PURPOSE: To assess the association between CBF and cerebral microstructural integrity. STUDY TYPE: Cross sectional. POPULATION: A total of 94 cognitively unimpaired adults (mean age 50.7 years, age range between 22 and 88 years, 56 Men). FIELD STRENGTH/SEQUENCE: A 3 T; pseudo-continuous arterial spin labeling (pCASL), diffusion tensor imaging (DTI), Bayesian Monte Carlo analysis of multicomponent driven equilibrium steady-state observation of T1 and T2 (BMC-mcDESPOT). ASSESSMENT: Lobar associations between CBF derived from pCASL, and longitudinal relaxation rate (R1 ), transverse relaxation rate (R2 ) and myelin water fraction (MWF) derived from BMC-mcDESPOT, or radial diffusivity (RD), axial diffusivity (AxD), mean diffusivity (MD) and fractional anisotropy (FA) derived from DTI were assessed. STATISTICAL TESTS: Multiple linear regression models were used using the mean region of interest (ROI) values for MWF, R1 , R2 , FA, MD, RD, or AxD as the dependent variable and CBF, age, age2 , and sex as the independent variables. A two-sided P value of <0.05 defined statistical significance. RESULTS: R1 , R2 , MWF, FA, MD, RD, and AxD parameters were associated with CBF in most of the cerebral regions evaluated. Specifically, higher CBF values were significantly associated with higher FA, MWF, R1 and R2 , or lower MD, RD and AxD values. DATA CONCLUSION: These findings suggest that cerebral tissue microstructure may be impacted by global brain perfusion, adding further evidence to the intimate relationship between cerebral blood supply and cerebral tissue integrity. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 4.

Demyelinating diseases of the central nervous system registry for patients with traditional Chinese medicine: Rationale and design of a prospective, multicenter, observational study.

Background: Traditional Chinese medicine (TCM), a main form of complementary and alternative medicine provides a potential possibility for demyelinating disease of the central nervous system (DDC) management and has been applied in considerable amounts of patients with this disorder. Nevertheless, powerful real-world evidences regarding the epidemiological and clinical characteristics, safety, and outcomes of TCM in DDC are lacking. The primary objective of the Demyelinating Diseases of the Central Nervous System Registry for Patients with Traditional Chinese Medicine (DATE-TCM) is to create an organized multicenter data collection structure to define integrative characteristics of DDC patients treated with TCM in an endeavor to fill these knowledge gaps to better inform clinical care and health policy. Method: This study provides a prospective and voluntary registry by using a web-based system. Baseline data will be recorded and subsequently regular follow-up visits will be implemented every 3-6 months for a total of 5 years. The primary outcome is Annualized Aggregate Relapse Rate at 5-year follow-up. Results: DATE-TCM is currently designed to capture the multidimensional (epidemiologic, demographic, clinical, etc.) features of DDC patients receiving TCM treatment, the type and long-term safety and efficacy of TCM intervenes in the DDC populations, as well as the interaction of TCM treatments and disease modifying therapies in the management of DDC, aiming to include 2000 eligible adult DDC patients with TCM intervenes from 35 participating centers, covering 77.4% of provincial administrative regions of mainland China. Conclusion: DATE-TCM is the first, largest, most geographically extensive, and standard registry-based observational study that systematically document the real-world data regarding the TCM application in the DDC populations, which will be extraordinarily important for clarifying the comprehensive characteristics and outcomes of TCM in DDC, further shed light on standardizing and optimizing the TCM measures for DDC management and establishing evidence-based clinical practice guidelines for TCM application in DDC.

Enhancing the efficacy of Hypericum perforatum in the treatment of an experimental model of multiple sclerosis using gold nanoparticles: an in vivo study.

Objective: Hypericum perforatum is a herbal medicine used in traditional medicine for the treatment of depression due to its antidepressant and anti-inflammatory activities. Therefore, we evaluated the therapeutic efficacy of H. perforatum extract (HPE) in combination with gold nanoparticles (HPE-GNP) against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Materials and Methods: EAE was induced in C57BL/6 mice with subcutaneous injection of MOG35-55 emulsified in complete Freund's adjuvant, and intraperitoneal pertussis toxin. Mice were treated with drugs in free (HPE) and nano-form (HPE-GNP) preparations. Splenocytes were isolated from all mice and the level of inflammatory and anti-inflammatory cytokines were evaluated by ELISA. The expression of T cells' transcription factors was also assessed using Real-Time PCR. Results: Clinical score was reduced after HPE-GNP treatment. This change was associated with a decrease in the incidence and infiltration of inflammatory cells into the central nervous system. Additionally, treatment with HPE-GNP decreased the level of pro-inflammatory cytokines (IFN-γ, IL-17A and IL-6) and increased anti-inflammatory cytokines (TGF-ß, IL-10 and IL-4). The real-time analysis revealed a decrease in the level of T-bet and ROR-γt but an increase in FoxP3 and GATA3 expression. Conclusion: The current study demonstrated that HPE-GNP could potentially reduce clinical and pathological complications of EAE, but laboratory data showed that HPE-GNP was significantly more effective than HPE in the treatment of EAE.

The effect of doxorubicin or cyclophosphamide treatment on auditory brainstem response in mice.

Clinical studies suggest that chemotherapy is associated with long-term cognitive impairment in some patients. Several underlying mechanisms have been proposed; however, the etiology of chemotherapy-related cognitive dysfunction remains relatively unknown. There is evidence that oligodendrocytes and white matter tracts within the CNS may be particularly vulnerable to chemotherapy-related damage and dysfunction. Auditory brainstem responses (ABRs) have been used to detect and measure functional integrity of myelin in a variety of animal models of autoimmune disorders and demyelinating diseases. Limited evidence suggests that increases in interpeak latencies, associated with disrupted impulse conduction, can be detected in ABRs following 5-fluorouracil administration in mice. It is unknown if similar functional disruptions can be detected following treatment with other chemotherapeutic compounds and the extent to which alterations in ABR signals represent robust and long-lasting impairments associated with chemotherapy-related cognitive impairment. Thus, C57BL/6 J mice were treated every 3rd day for a total of 3 injections with low or high dose cyclophosphamide, or doxorubicin. ABRs of mice were assessed on days 1, 7, 14, 56 and 6 months following completion of chemotherapy administration. There were timing and amplitude differences in the ABRs of the doxorubicin and the high dose cyclophosphamide groups relative to the control animals. However, despite significant toxic effects as assessed by weight loss, the changes in the ABR were transient.

Astragalus species: Phytochemistry, biological actions and molecular mechanisms underlying their potential neuroprotective effects on neurological diseases.

Neurodegenerative and neuropsychiatric illnesses are prevalent and life-threatening disorders characterized by a wide range of clinical syndromes and comorbidities, all of which have complex origins and share common molecular pathomechanisms. Although the pathophysiology of neurological illnesses is not completely understood, researchers have discovered that several ion channels and signalling pathways may have played a role in disease pathogenesis. Active substances from Astragalus sp. are being employed for nutrition, and their usefulness in the treatment of neurological illnesses is receiving more attention. Because their extracts and active components exert different pharmacological effects on a variety of ailments, they have a long history of usage as a cure for various diseases. This review summarizes the research work on Astragalus and their biologically active constituents as potential candidates for the protection against and treatment of neurodegenerative and neuropsychiatric disorders to show the potential efficacy of Astragalus sp. and its active ingredients in treating some neurological diseases. Simultaneously, the chemical structures of these active compounds, their sources, biological properties, and mechanisms are also listed. In ethnopharmacological applications, Astragalus membranaceus and spinosus have been studied as traditional medicines worldwide. The chemical constituents of Astragalus species mainly comprise terpenoids, flavonoids, and polysaccharides. The extracts and phytochemical compounds of Astragalus species exhibit various pharmacological activities, including antioxidant, anti-inflammatory, anticancer, antitumor, anticonvulsive, immunomodulatory, and other activities. Based on the current literature, we conclude that Astragalus is a promising dietary herb with multiple potential signal modulating applications that mainly include the modulation of neurotransmitters and receptors, anti-inflammatory activities, inhibition of amyloid aggregation, induction of myelin sheath repair and neurogenesis, as well as activation of the signalling pathways relevant to neurological diseases.

Proteomic Mapping of the Human Myelin Proteome.

Alzheimer's disease (AD) is a degenerative cognitive condition that affects individuals with an increasing prevalence in older age groups. There are currently five drugs on the market for AD but no new effective ones have been discovered for decades. There has been increasing interest in the use of natural remedies such as special diets and plant extracts but these require further study. Based on the known effects on white matter and neuronal conductance in Alzheimer's disease, we present a protocol for proteomic analysis of myelin-enriched brain fractions as a way of identifying potential biomarkers of efficacy. This fingerprint could be used in screening assays for novel compounds for treatment of AD.

A review on neuropharmacological role of erucic acid: an omega-9 fatty acid from edible oils.

Neurodegenerative diseases (ND) are characterised by loss of neurons in the brain and spinal cord. For the normal functioning of the brain, divers group of fatty acids in the form of glycerophospholipids, glycerol ether lipids, cerebrosides, sulfatides, and gangliosides are essential. They are present abundantly in the nervous system and are actively involved in both the development and maintenance of the nervous system. A dietary deficiency of essential fatty acid during development results in hypomyelination state which affects various neuronal functions. Several studies suggested that age remains the primary risk factor for almost all neurodegenerative disorders. The potential contribution of these fatty acids in the progression of neurodegenerative disorders is indispensable. Erucic acid an omega 9 fatty acid, which is obtained from edible oils has proven to cause myocardial lipidosis, heart lesions and hepatic steatosis in animals therefore, its content in edible oils is restricted to certain levels by regulatory agencies. However, erucic acid in the form of a mixture with oleic acid is often used as a dietary treatment for the management of adrenoleukodystrophy without any cardiotoxicity. Our literature search revealed that, erucic acid reported to enhance cognitive function, interact with peroxisome proliferator activated receptors (PPARs), inhibit elastase and thrombin. In this review first we have attempted to describe the relationship between fatty acids and neurodegeneration followed by a description on the pharmacology of erucic acid. The overall purpose of this review is to analyse toxic and beneficial neuropharmacological effects of erucic acid.

Liuwei Dihuangtang Alleviates Myelin Injury in Anterior Cingulate Cortex and Depression-like Behaviors of Rats with Diabetes Mellitus and Depression via Promoting Autophagy and Regulating Microglial Phenotype / 中国实验方剂学杂志

ObjectiveTo observe the effect of Liuwei Dihuangtang （LWDHT） on depression-like behaviors of rats with diabetes mellitus and depression （DD） and explore its mechanism. MethodThe diabetes mellitus （DM） model was induced by the high-fat diet and tail vein injection of low-dose streptozotocin （STZ） in 50 male Sprague-Dawley rats of SPF grade. Then the DD model was induced by chronic unpredictable mild stress （CUMS） for 28 days in DM rats. Fifty DD rats were randomly divided into model group， fluoxetine group （10 mg·kg-1·d-1）， and low-， medium-， and high-dose LWDHT groups （3.375， 6.75， 13.5 g·kg-1·d-1）， with 10 rats in each group. Another 10 healthy rats were assigned into a control group and received normal saline by gavage. After four weeks of drug intervention， the forced swimming assay was carried out to assess the depression-like behaviors of rats. The expression levels of tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， interleukin-4 （IL-4）， and interleukin-10 （IL-10） in the anterior cingulate cortex （ACC） were detected by enzyme-linked immunosorbent assay （ELISA）. Immunofluorescence was used to detect the expression of myelin basic protein （MBP） in ACC and the co-localization of ionized calcium-binding adapter molecule 1 （Iba1） with intracellular microtubule-associated protein 1 light chain 3 （LC3）. The protein expression levels of MBP， myelin proteolipid protein （PLP）， myelin oligodendrocyte glycoprotein （MOG）， Beclin-1， LC3， p62， and microglia （MG） phenotypic protein-related inducible nitric oxide synthase （iNOS）， and arginase 1 （Arg1） were detected by Western blot. ResultCompared with the control group， the model group showed shortened swimming time and prolonged immobility time （P<0.01）. Compared with the model group， the medium- and high-dose LWDHT groups showed reduced immobility time （P<0.05， P<0.01）. Compared with the control group， the model group showed decreased protein expression of MBP， PLP， and MOG in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed up-regulated protein expression of MBP， PLP， and MOG （P<0.05， P<0.01）. Compared with the control group， the model group showed decreased MBP fluorescence intensity in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed increased MBP fluorescence intensity in the ACC region （P<0.05， P<0.01）. Compared with the control group， the model group showed increased expression of iNOS （P<0.01） and slightly increased Arg1 protein expression. Compared with the model group， the medium- and high-dose LWDHT groups and the fluoxetine group showed down-regulated iNOS expression and up-regulated Arg1 protein expression （P<0.05， P<0.01）， but there was no significant difference between the fluoxetine group and the medium-，high-dose LWDHT groups. Compared with the control group， the model group showed increased expression levels of proinflammatory factors IL-1β and TNF-α in the ACC region （P<0.01） and slightly increased expression levels of anti-inflammatory factors IL-4 and IL-10. Compared with the model group， the fluoxetine group， and the medium- and high-dose LWDHT groups showed down-regulated expression of IL-1β and TNF-α （P<0.05， P<0.01） and up-regulated expression of IL-4 and IL-10 （P<0.05， P<0.01）. Compared with the control group， the model group showed reduced expression levels of Beclin-1 and LC3Ⅱ （P<0.01） and increased expression level of p62 （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed up-regulated Beclin-1 and LC3Ⅱ expression （P<0.01） and down-regulated p62 expression （P<0.01）. Compared with the control group， the model group showed decreased LC3+Iba1+ cells in the ACC region （P<0.01）. Compared with the model group， the fluoxetine group and the medium- and high-dose LWDHT groups showed increased LC3+Iba1+ cells （P<0.05， P<0.01）. ConclusionLWDHT can alleviate the depression-like behaviors in DD rats presumedly by promoting MG autophagy， regulating MG phenotypic changes， and increasing MG clearance of myelin sheath fragments. Meanwhile， MG phenotypic transformation also inhibits ACC inflammation in DD rats， improves the local microenvironment of oligodendrocyte proliferation and differentiation， and ultimately promotes the repair and remyelination of damaged myelin sheath.

Serum Levels of the Biomarkers Associated with Astrocytosis, Neurodegeneration, and Demyelination: Neurological Benefits of Citicoline Treatment of Patients with Ischemic Stroke and Atrial Fibrillation.

Ischemic stroke is a main complication of atrial fibrillation (cardiac arrhythmia). The aim of our study was to estimate the effects of citicoline (CDP-choline) therapy on the levels of circulating neurospecific protein markers in serum of the patients with ischemic stroke and atrial fibrillation. Fiftyfour patients (mean age 76 years) treated with citicoline in a dose of 2.0 g daily intravenously for 12 to 14 days in addition to basic treatment formed the examined group. Thirty-two patients (mean age 68.5 years) obtained only standard therapy and formed the control group. Serum levels of neuronal and glial protein markers, including glial fibrillary acidic protein (GFAP), a neurofilament light subunit (NF-L), myelin basic protein (MBP), and ionized calcium-binding adaptor molecule 1 (Iba1), were measured in patients of both groups before and after treatment; an immunoblotting technique followed by densitometry analysis were used. Supplementary citicoline treatment provided significant reductions of the levels of GFAP (33%, P = 0.034), NF-L (27%, P = 0.019), and MBP (32%, P = 0.018), as compared to the initial values, while there were no marked changes in the studied parameters in the control group. The results obtained allow us to hypothesize that therapeutic benefit of citicoline in patients with ischemic stroke and atrial fibrillation can be mediated through increasing neuronal viability, protecting against axonal injury, decreasing the level of reactive astrogliosis, preventing deficiencies in the blood-brain integrity, and reducing the intensity of demyelination. However, citicoline administration exerted no effect on the blood content of microglial marker Iba-1, thus possibly preserving an important functional significance of microglia, which is needed to resolve local inflammation and clear cellular debris, and also provide protective factors to reduce cell injury in the ischemic brain. The obtained results indicate that serum levels of neurospecific biomarkers are significant and clinically relevant indices of the efficiency of treatment of the above-mentioned pathologies and can be used for further investigations of the stroke pathophysiology and molecular mechanisms of nootropic-mediated neuroprotection.

Citrullinated myelin induces microglial TNFα and inhibits endogenous repair in the cuprizone model of demyelination.

BACKGROUND: Microglia are the primary phagocytes of the central nervous system and are responsible for removing damaged myelin following demyelination. Previous investigations exploring the consequences of myelin phagocytosis on microglial activation overlooked the biochemical modifications present on myelin debris. Such modifications, including citrullination, are increased within the inflammatory environment of multiple sclerosis lesions. METHODS: Mouse cortical myelin isolated by ultracentrifugation was citrullinated ex vivo by incubation with the calcium-dependent peptidyl arginine deiminase PAD2. Demyelination was induced by 6 weeks of cuprizone (0.3%) treatment and spontaneous repair was initiated by reversion to normal chow. Citrullinated or unmodified myelin was injected into the primary motor cortex above the cingulum bundle at the time of reversion to normal chow and the consequent impact on remyelination was assessed by measuring the surface area of myelin basic protein-positive fibers in the cortex 3 weeks later. Microglial responses to myelin were characterized by measuring cytokine release, assessing flow cytometric markers of microglial activation, and RNAseq profiling of transcriptional changes. RESULTS: Citrullinated myelin induced a unique microglial response marked by increased tumor necrosis factor α (TNFα) production both in vitro and in vivo. This response was not induced by unmodified myelin. Injection of citrullinated myelin but not unmodified myelin into the cortex of cuprizone-demyelinated mice significantly inhibited spontaneous remyelination. Antibody-mediated neutralization of TNFα blocked this effect and restored remyelination to normal levels. CONCLUSIONS: These findings highlight the role of post-translation modifications such as citrullination in the determination of microglial activation in response to myelin during demyelination. The inhibition of endogenous repair induced by citrullinated myelin and the reversal of this effect by neutralization of TNFα may have implications for therapeutic approaches to patients with inflammatory demyelinating disorders.

Proteomic and lipidomic profiling of demyelinating lesions identifies fatty acids as modulators in lesion recovery.

After demyelinating injury of the central nervous system, resolution of the mounting acute inflammation is crucial for the initiation of a regenerative response. Here, we aim to identify fatty acids and lipid mediators that govern the balance of inflammatory reactions within demyelinating lesions. Using lipidomics, we identify bioactive lipids in the resolution phase of inflammation with markedly elevated levels of n-3 polyunsaturated fatty acids. Using fat-1 transgenic mice, which convert n-6 fatty acids to n-3 fatty acids, we find that reduction of the n-6/n-3 ratio decreases the phagocytic infiltrate. In addition, we observe accelerated decline of microglia/macrophages and enhanced generation of oligodendrocytes in aged mice when n-3 fatty acids are shuttled to the brain. Thus, n-3 fatty acids enhance lesion recovery and may, therefore, provide the basis for pro-regenerative medicines of demyelinating diseases in the central nervous system.

[Effects of electroacupuncture on myelin-related protein in corpus callosum of rats with focal cerebral ischemia].

OBJECTIVE: To observe the effect of electroacupuncture(EA)on the expression of myelin basic protein (MBP), axon growth inhibitor Nogo-A and Nogo receptor (NgR) in corpus callosum of rats with focal cerebral ischemia, so as to explore the mechanism of EA underlying improving ischemic white matter injury. METHODS: Fourty male SD rats were randomly divided into normal, sham operation, model and EA groups, with 10 rats in each group. The focal cerebral ischemia rat model was established by occlusion of the middle cerebral artery (MCAO). EA was applied to "Baihui"(GV20) and "Zusanli"(ST36) on the left side for 30 min, once daily for 14 days. Neurological function score and the adhensive removal test were used to evaluate neurological deficit severity; Hematoxylin-esion staining was used to observe the pathological changes in myelin of corpus callosum and luxol fast blue（LFB） staining was used to observe the myelin of corpus callosum. Immunohistochemical staining and Western blot were used to detect the expressions of MBP、Nogo-A and NgR in the ischemic corpus callosum. RESULTS: After MCAO, the neurological function score was significantly increased (P<0.05), the time required for contact with tape and tape removal was longer (P<0.001), the intensity of LFB staining and the expression of MBP decreased, while the veside area and the expression of Nogo-A and its receptor NgR increased (P<0.01, P<0.05) in the model group relevant to the normal and sham operation groups. The fiber arrangement of the corpus callosum on the ischemic side was disordered and a large amount of myelin sheath was lost in the model group. Following the treatment, the neurological deficit score of EA group was gradually decreased and significantly decreased on the 3rd, 7th and 14th day (P<0.05), and the time to remove the adhesive tape was shortened at the 7th and 14th day (P<0.001). The shape of the corpus callosum in the EA group was close to normal, and the myelin structure was relatively complete. The intensity of LFB staining and the expression of MBP was increased (P<0.05, P<0.01) while the expression of Nogo-A and its receptor NgR were decreased in the EA group relevant to the model group (P<0.01). CONCLUSION: EA can play a protective role in myelin of the corpus callosum after cerebral ischemia, which may be related to down-regulating the expressions of Nogo-A and NgR.

CNS Hypomyelination Disrupts Axonal Conduction and Behavior in Larval Zebrafish.

Myelination is essential for central nervous system (CNS) formation, health and function. As a model organism, larval zebrafish have been extensively employed to investigate the molecular and cellular basis of CNS myelination, because of their genetic tractability and suitability for non-invasive live cell imaging. However, it has not been assessed to what extent CNS myelination affects neural circuit function in zebrafish larvae, prohibiting the integration of molecular and cellular analyses of myelination with concomitant network maturation. To test whether larval zebrafish might serve as a suitable platform with which to study the effects of CNS myelination and its dysregulation on circuit function, we generated zebrafish myelin regulatory factor (myrf) mutants with CNS-specific hypomyelination and investigated how this affected their axonal conduction properties and behavior. We found that myrf mutant larvae exhibited increased latency to perform startle responses following defined acoustic stimuli. Furthermore, we found that hypomyelinated animals often selected an impaired response to acoustic stimuli, exhibiting a bias toward reorientation behavior instead of the stimulus-appropriate startle response. To begin to study how myelination affected the underlying circuitry, we established electrophysiological protocols to assess various conduction properties along single axons. We found that the hypomyelinated myrf mutants exhibited reduced action potential conduction velocity and an impaired ability to sustain high-frequency action potential firing. This study indicates that larval zebrafish can be used to bridge molecular and cellular investigation of CNS myelination with multiscale assessment of neural circuit function.SIGNIFICANCE STATEMENT Myelination of CNS axons is essential for their health and function, and it is now clear that myelination is a dynamic life-long process subject to modulation by neuronal activity. However, it remains unclear precisely how changes to myelination affects animal behavior and underlying action potential conduction along axons in intact neural circuits. In recent years, zebrafish have been employed to study cellular and molecular mechanisms of myelination, because of their relatively simple, optically transparent, experimentally tractable vertebrate nervous system. Here we find that changes to myelination alter the behavior of young zebrafish and action potential conduction along individual axons, providing a platform to integrate molecular, cellular, and circuit level analyses of myelination using this model.