Nerves Of Mice Research Articles

Electroacupuncture alleviates paclitaxel-induced peripheral neuropathy by reducing CCL2-mediated macrophage infiltration in sensory ganglia and sciatic nerve

BackgroundPaclitaxel-induced peripheral neuropathy (PIPN) is prevalent among patients receiving paclitaxel chemotherapy, which results in sensory abnormality as well as neuropathic pain. Conventional medications lack effectiveness on PIPN. Clinical trials identified beneficial effects of acupuncture on PIPN among patients receiving chemotherapy. Here we explored the mechanisms underlying how acupuncture might alleviate PIPN.MethodsA mouse model of PIPN was established by repeated paclitaxel application. Electroacupuncture (EA) was applied at ST36 and BL60 acupoints of model mice. Immunostaining, flow cytometry, behavioral assay, in vivo imaging were utilized for effects determination and mechanism exploration.ResultsEA ameliorated mechanical and cold pain hypersensitivities, reduced sensory neuron damage and improved loss in intra-epidermal nerve fibers (IENFs) in model mice. Macrophages infiltration were detected in DRG and sciatic nerve of model mice, which was reduced by EA. EA affected M1-like pro-inflammatory macrophage infiltration in DRG, whereas it did not affect M2-like macrophages. DRG neurons released chemoattractant CCL2 that recruited macrophages via CCR2 to DRG. EA reduced CCL2 overproduction by DRG neurons and reduced macrophage infiltration. Blocking CCR2 mimicked EA’s anti-allodynic effect, whereas exogenously applying recombinant CCL2 reversed the ameliorative effect of EA on macrophage infiltration and abolished EA’s anti-allodynia on model mice. EA ameliorated other signs of PIPN, including sensory neuron damage, sciatic nerve morphology impairment and IENFs loss. In mice inoculated with breast cancer cells, EA didn’t affect paclitaxel-induced antitumor effect.ConclusionsThese findings suggest EA alleviates PIPN by reducing CCL2/CCR2 mediated-pro-inflammatory macrophage infiltration into sensory ganglia as well as the sciatic nerve. Our study supports EA could be used as a potential non-pharmacological therapy for PIPN.

Human umbilical cord mesenchymal stem cell-derived exosomes combined with mouse nerve growth factor can more effectively ameliorate the motor disorder and brain pathological injury in mice with cerebral palsy.

Cerebral palsy (CP) is a neurodevelopmental disorder and motor disorder syndrome. It has been confirmed that mesenchymal stem cells (MSCs) and mouse nerve growth factor (mNGF) can repair brain tissue damage and nerve injury; however, exosomes derived from healthy cells may have a comparable therapeutic potential as the cells themselves. The purpose of this study was to explore the improvement effect of human umbilical cord mesenchymal stem cell (hUC-MSCs)-derived exosomes on a CP model and determine whether there is a synergistic effect when combined with mNGF. Exosomes were isolated from hUC-MSCs and examined using transmission electron microscopy (TEM), particle size and western blot (WB). A total of 38 BALB/c mice (male, postnatal day 6 (PND6)) were randomly divided into 5 groups: sham group, CP group, CP-exo group, CP-mNGF group, and CP-exo-mNGF group. Hypoxic induction after unilateral common carotid artery ligation combined with lipopolysaccharide (LPS) infection was used to construct the CP model. Pathological damage to neuron tissue and synaptic structures in the hippocampus was confirmed using light microscopy after hematoxylin-eosin (H&E) staining and TEM, respectively. Survival of neurons was evaluated using Nissl staining. Western blot was applied to monitor PSD-95 and synaptophysin (SYN) protein levels. This study indicated that exosomes released by hUC-MSCs ameliorated brain damage and synaptic structure destruction in CP mice induced by hypoxic ischemia and LPS infection. When combined with mNGF, there was more effective improvement. In the CP group, neuronal function was severely impaired; however, hUC-MSCs-derived exosomes and mNGF improved it. PSD-95 and SYN proteins were presynaptic and postsynaptic proteins, respectively. Interestingly, the PSD-95 and SYN protein levels were significantly lower in the CP mice, but with the addition of hUC-MSCs-exosomes or mNGF, they increased significantly, especially in the CP-exo-mNGF group. The nerve function injury in CP can be improved the most when hUC-MSCs-derived exosomes are combined with mNGF through intraperitoneal (ip.) administration.

Tracking adipose-derived stem cell exosomes applied in a mouse crush injury model: insights from fluorescent labeling and spatial transcriptomics - an experimental study.

Adipose-derived stem cell exosomes (ADSC-exos) are promising for nerve regeneration; however, their precise mechanisms remain unclear. This study employed fluorescent labeling and spatial transcriptomics to track the effects of ADSC-exos on crushed sciatic nerves in mice. Labeled exosomes were detected in spinal neurons and proximal nerve segments after application. Spatial transcriptomics revealed significant changes in gene expression, with an upregulation of neurons and Schwann cells and the downregulation of oligodendrocytes. The key pathways affected were prosaposin, pleiotrophin, fibroblast growth factor, secreted phosphoprotein 1, SLIT and NTRK-like family, member, vascular endothelial growth factor, and growth arrest-specific protein. ADSC-exo treatment enhanced cell-cell interactions, particularly between Schwann cells and astrocytes, thereby promoting a regenerative environment. Gene ontology analysis suggested improvements in metabolic activity, cell communication, and structural support. This study highlights the complex interplay between multiple cell types and signaling pathways involved in the nerve regeneration response to ADSC-exos. This comprehensive approach offers new perspectives on the role of ADSC-exos in nerve regeneration and paves the way for advanced regenerative strategies for peripheral nerve injuries.

Targeting the neonatal Fc receptor (FcRn) is not beneficial in an animal model of chronic neuritis

The inhibition of the neonatal Fc receptor (FcRn) is a promising therapeutic pathway in certain autoimmune disorders to reduce the amount of circulating pathogenic IgG autoantibodies by interfering with their recycling system. FcRn antibodies are currently being tested in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). This study aimed to investigate the therapeutic potential of an antibody targeting FcRn in the intracellular adhesion molecule 1 (ICAM1)-deficient NOD mouse—a model representative for many aspects of human CIDP. After the onset of clinical signs of neuropathy, ICAM1-deficient NOD mice were assigned to treatment twice per week with anti-FcRn antibody, isotype control antibody (negative control) or intraperitoneal (administered) immunoglobulin (positive control). Disease severity was monitored using disease-specific assessments for ataxia and paresis such as grip strength measurements. Serum immunoglobulin levels and peripheral nerve immune cell infiltration were quantified. Treatment with anti-FcRn antibody did not ameliorate disease progression, as determined by clinical scores and grip strength analysis. Disease progression was reduced in the positive control animals receiving immunoglobulin. Consistent with the clinical results, the composition of infiltrating immune cells was not altered in the peripheral nerve of anti-FcRn antibody-treated mice compared to controls. However, in anti-FcRn antibody-treated mice, significantly lower IgG levels were detectable compared to controls. These findings suggest that targeting the FcRn recycling system does not influence disease progression in the NOD-ICAM1-deficient mouse model of CIDP. Further studies will elucidate whether the reduction of IgG levels was insufficient to deplete pathogenic autoantibodies or whether the major inflammatory driver in the NOD-ICAM1-deficient mouse animal model is mediated by factors other than pathological immunoglobulins.

High-resolution imaging atlas reveals the context-dependent role of pancreatic sympathetic innervation in diabetic mice.

A better understanding of how sympathetic nerves impact pancreatic function is helpful for understanding diabetes. However, there is still uncertainty and controversy surrounding the roles of sympathetic nerves within the pancreas. To address this, we utilize high-resolution imaging and advanced three-dimensional (3D) reconstruction techniques to study the patterns of sympathetic innervation and morphology in the islets of adult wild-type (WT) and diabetic mice. Our data show that more than ~30% of α/β-cells are innervated by sympathetic nerves in both WT and diabetic mice. Additionally, sympathetic innervated α/β-cells are reduced in diet-induced obese (DIO) mice, whereas sympathetic innervated β-cells are increased in db/ db mice. In addition, in situ chemical pancreatic sympathetic denervation (cPSD) improves glucose tolerance in WT and db/ db mice but decreases glucose tolerance in DIO mice. In situ cPSD also enhances insulin sensitivity in diabetic mice without affecting WT mice. Overall, our findings advance our understanding of diabetes by highlighting the distinctive impact of pancreatic sympathetic innervation on glucose regulation.

Realizing real-time optical molecular imaging in peripheral nerve tissue via Rhodamine B.

Iatrogenic nerve injury is a consequential complication during surgery. Thus, real-time imaging of peripheral nerve (PN) possesses significant clinical implications. In recent years, the rapid advancements in optical molecular imaging (OMI) technology have provided essential technical foundations for the implementation of PN fluorescence imaging. This study aimed to realize real-time OMI of PNs via Rhodamine B. Phosphate buffered saline (PBS), normal saline (NS), 5% glucose solution (GS), and fetal bovine serum (FBS) were selected for measuring the fluorescence spectra of Rhodamine B solutions prepared in each formulation. Rhodamine B solutions, with varying doses dissolved in 100 μL of each formulation, were prepared and applied to the exposed PNs of the mice for incubation later. To ascertain the optimal formulation and dose of Rhodamine B, an analysis was performed on the signal-to-background ratio (SBR) of the nerves. Based on the experimental results, we proceeded to incubate Rhodamine B solution on the PN tissue of mice and human subjects, as well as on neuronal cells, to verify the binding sites of Rhodamine B with nerve. Subsequently, histological studies were conducted to validate the binding site between Rhodamine B and the nerves. Finally, we injected the optimal combination of Rhodamine B solution into mice via the tail vein and collected the SBR of mouse nerve tissues at different time intervals to determine the optimal pre-injection time. Fluorescence images of various tissues were collected, and Hematoxylin and Eosin (H&E) staining results were observed to determine the metabolism of Rhodamine B in mice and its toxicity. The excitation peak of Rhodamine B in PBS, NS, 5% GS, and FBS formulations was 554 nm, and the emission peak was 576 nm. In PBS group, the maximum SBR was 15.37 ± 0.68 while the dose of Rhodamine B was 8 nmol. Through ex-vivo validation on fresh human nerve tissue and verification using mouse and human tissue sections, we observed fluorescent signals of Rhodamine Bin the regions of nerve tissue and the fluorescence signals were all concentrated on the neuronal cell membranes. After injection, the fluorescent signal in nerve tissue reached its peak at 24 hours (h), coinciding with the highest SBR (5.93 ± 0.92) in mouse nerve tissues at this time point. Additionally, the fluorescence signal could be maintained for at least 48 h. Within 24 h, lung dilation and fusion of alveoli occurred. Then these pathological manifestations gradually diminished, returning to normal at 2 weeks (w), with no significant acute or chronic adverse reactions observed in other tissues. Rhodamine B enables fluorescence imaging of PNs and has the potential for clinical translation.

Differential regulation of tissue-resident and blood-derived macrophages in models of autoimmune and traumatic peripheral nerve injury.

The current study focuses on understanding the functional role of different subsets of endoneurial macrophages in autoimmune polyneuropathies (AP) and traumatic peripheral nerve injury (TPNI), which holds potential for clinical application. Recent studies have advanced our understanding of the diverse origins of macrophages within peripheral nerves. However, there remains a gap in our knowledge regarding how endoneurial macrophages from different origins affect disease progression in AP versus TPNI. Flow cytometry was utilized to analyze macrophage phenotypes, including polarization states, cytokine production, and myelin phagocytosis in animal models of AP and TPNI. This study focuses on two distinct origins of macrophages, namely CD11b+F4/80hi tissue-resident (TRM) and CD11b+F4/80int blood-derived macrophages (BDM). The study utilized two animal models: the first was the spontaneous autoimmune peripheral polyneuropathy (SAPP) model in B7.2-null non-obese diabetic (NOD-B7.2-/-) mice, which serves as a model for inflammatory demyelinating polyneuropathy; the second model involved wild type C57BL/6 mice subjected to sciatic nerve crush injury, modeling TPNI. Behavioral, electrophysiological, and histological analyses were performed to assess peripheral nerve injury. The study found that pro-inflammatory M1 macrophage polarization and tumor necrosis factor-alpha production by macrophages were more pronounced in the peripheral nerves of SAPP mice compared to those with TPNI, with the majority of these macrophages being TRM. In contrast, endoneurial macrophages in mice with TPNI were mainly BDM, exhibiting a less defined macrophage polarization and cytokine profile than TRM in AP mice. Interestingly, myelin phagocytosis was primarily driven by BDM in both SAPP and TPNI mice. This study offers novel insights into origin-dependent macrophage functions in AP and TPNI. Furthermore, these findings may help the future development of novel therapies targeting macrophage subsets of specific origin in AP and TPNI.

A vagus nerve dominant tetra-synaptic ascending pathway for gastric pain processing

Gastric pain has limited treatment options and the mechanisms within the central circuitry remain largely unclear. This study investigates the central circuitry in gastric pain induced by noxious gastric distension (GD) in mice. Here, we identified that the nucleus tractus solitarius (NTS) serves as the first-level center of gastric pain, primarily via the vagus nerve. The prelimbic cortex (PL) is engaged in the perception of gastric pain. The lateral parabrachial nucleus (LPB) and the paraventricular thalamic nucleus (PVT) are crucial regions for synaptic transmission from the NTS to the PL. The glutamatergic tetra-synaptic NTS–LPB–PVT–PL circuitry is necessary and sufficient for the processing of gastric pain. Overall, our finding reveals a glutamatergic tetra-synaptic NTS–LPB–PVT–PL circuitry that transmits gastric nociceptive signaling by the vagus nerve in mice. It provides an insight into the gastric pain ascending pathway and offers potential therapeutic targets for relieving visceral pain.

CNSC-13. CROSSTALK BETWEEN SENSORY NEURONAL ACTIVITY AND TUMOR CELLS PROMOTES MALIGNANCY AND CANCER PAIN

Abstract BACKGROUND Nerve infiltration of solid tumors is associated with poor prognosis in multiple cancer types. Understanding the role of neuronal activity in cancer progression offers innovative approaches for treating malignancies and cancer-associated neurological issues such as pain. Pain perception is mediated by the activity of peripheral sensory neurons. Many cancer types induce pain, and sensory innervation could support tumor growth, raising the interesting hypothesis that cancer pain-associated neuronal activity promotes malignancies. Our study aims to test the hypothesis using malignant peripheral nerve sheath tumor (MPNST) as the experimental platform. METHODS in vivo allograft models were established by implanting mouse MPNST cells into the sciatic nerves of male and female mice, followed by performing pain behavior assays (von Frey, Hargreaves, and conditioned place preference tests) and tumor growth measurements. Primary mouse dorsal root ganglion (DRG) sensory neuron cultures were prepared for calcium imaging and neuron-tumor co-culture experiments. RESULTS MPNST tumor-bearing mice exhibited hypersensitivity to noxious and non-noxious stimuli (evoked pain) and ongoing pain, compared to the sham controls. MPNST-conditioned media increased intracellular calcium concentration and ATF3 (indicator for nerve injury/stress) expression in primary sensory neuron culture, suggesting that MPNST tumor cell secretory factors may induce pain by triggering sensory neuron injury/stress responses that increase sensory neuron activity/sensitivity. Reciprocally, we found that stimulation of sensory neuron activity accelerates MPNST tumor growth. The conditioned media from stimulated sensory neurons increased tumor proliferation (EdU assay) in vitro, suggesting that sensory neuron activity-induced paracrine factors increase MPNST cell growth. CONCLUSIONS MPNST is a devastating cancer that grows within peripheral nerves which induce intractable pain. Our findings demonstrate a feedforward cycle where the cancer cells induce sensory neuron hypersensitivity/hyperactivity (pain) which in turn further accelerates tumor growth. Future studies will identify the molecular mechanisms underlying this crosstalk between MPNST and sensory neuron activity.

P66shc deficiency attenuates high glucose-induced autophagy dysfunction in Schwann cells.

Schwann cells are the most abundant cells in the peripheral nervous system, maintaining the development, function and regeneration of peripheral nerves. Defects in these Schwann cells injury response potentially contribute to the pathogenesis of diabetic peripheral neuropathy (DPN), a common complication of diabetes mellitus. The protein p66shc is essential in regulating oxidative stress responses, autophagy induction and cell survival, and is also vital in the development of DPN. In this study, we hypothesized that p66shc mediates high glucose-induced oxidative stress and autophagic dysfunction. In Schwann cells treated with high glucose; p66shc expression, levels of reactive oxygen species, autophagy impairment, and early apoptosis were elevated. Inhibition of p66shc gene expression by siRNA reversed high glucose-induced oxidative stress, autophagy impairment, and early apoptosis. We also demonstrated that the levels of p66shc was increased, while autophagy-related proteins p62 and LC3 (LC3-II/I) were suppressed in the sciatic nerve of streptozotocin-induced diabetes mice. P66shc-deficient mice exhibited the improvement in autophagy impairment after diabetes onset. Our findings suggest that the p66 plays a crucial role in Schwann cell dysfunction, identifying its potential as a therapeutic target.

Therapeutic effect of Marrubium vulgare L. Aqueous extract on chronic constriction injury of sciatic nerve-induced neuropathic pain in mice

Marrubium vulgare L. leaves have long been recognised in Moroccan traditional medicine for their effectiveness in managing pain and inflammation. However, their potential is in treating peripheral neuropathic pain. This study aimed to investigate the effects of M. vulgare aqueous extract (AEMV) on peripheral neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve in mice. This research represents the first exploration of AEMV’s therapeutic potential in neuropathic pain management. AEMV was initially analysed using HPLC MS/MS to identify its predominant compound, Marrubiin. Mice underwent CCI surgery to induce neuropathic pain. AEMV was administered orally and Clomipramine served as a positive control. Chronic administration of AEMV significantly attenuated thermal, mechanical, and cold sensitivity induced by CCI. It also promoted functional and histological recovery of the sciatic nerve.

Pharmacologically increasing cGMP improves proteostasis and reduces neuropathy in mouse models of CMT1

Increasing cyclic GMP activates 26S proteasomes via phosphorylation by Protein Kinase G and stimulates the intracellular degradation of misfolded proteins. Therefore, agents that raise cGMP may be useful therapeutics against neurodegenerative diseases and other diseases in which protein degradation is reduced and misfolded proteins accumulate, including Charcot Marie Tooth 1A and 1B peripheral neuropathies, for which there are no treatments. Here we increased cGMP in the S63del mouse model of CMT1B by treating for three weeks with either the phosphodiesterase 5 inhibitor tadalafil, or the brain-penetrant soluble guanylyl cyclase stimulator CYR119. Both molecules activated proteasomes in the affected peripheral nerves, reduced polyubiquitinated proteins, and improved myelin thickness and nerve conduction. CYR119 increased cGMP more than tadalafil in the peripheral nerves of S63del mice and elicited greater biochemical and functional improvements. To determine whether raising cGMP could be beneficial in other neuropathies, we first showed that polyubiquitinated proteins and the disease-causing protein accumulate in the sciatic nerves of the C3 mouse model of CMT1A. Treatment of these mice with CYR119 reduced the levels of polyubiquitinated proteins and the disease-causing protein, presumably by increasing their degradation, and improved myelination, nerve conduction, and motor coordination. Thus, pharmacological agents that increase cGMP are promising treatments for CMT1 neuropathies and may be useful against other proteotoxic and neurodegenerative diseases.

Ameliorative Effect of Hedysarum polybotrys Polysaccharide on Neural Tissue Fibrosis in Diabetic Peripheral Neuropathy Mice and its Mechanisms

Objective: This study aimed to investigate the role of Hedysarum polybotrys polysaccharide (HPS) in ameliorating neural tissue fibrosis in diabetic peripheral neuropathy (DPN) mice. Methods: Fifty DPN mice were selected and randomly divided into five groups (n = 10), which were the model group, positive control group (receiving only 4 mg/(kg-d) of α-lipoic acid), high-dose HPS group (200 mg/(kg-d) of HPS was given per day), medium-dose HPS group (100 mg/(kg-d) of HPS was given per day), and low-dose HPS group (50 mg/(kg-d) of HPS given daily). In addition, non-diabetic C57BL/6 wild-type mice were selected as the normal group (n = 10). The expression levels of Keap1 and Nrf2 proteins and their mRNAs in the sciatic nerve tissues of mice in each group were analyzed by Western blot technique and real-time fluorescence quantitative PCR. Results: Compared with the normal group, the expression of Keap1 protein and mRNA was increased, while the expression of Nrf2 protein and mRNA was decreased in the sciatic nerve of mice in the model group (P < 0.05). Compared with the model group, Keap1 protein and mRNA expression decreased, while Nrf2 protein and mRNA expression increased in the control and high and medium dose HPS groups of mice (P < 0.05). Conclusion: HPS may inhibit fibrosis of neural tissue and ameliorate nerve injury in DPN mice by regulating the Keap1/Nrf2 signaling pathway. This effect was associated with enhanced antioxidant capacity, promotion of Nrf2 activation, and increased antioxidant gene expression by HPS. Therefore, HPS has a potential therapeutic value to ameliorate DPN-associated nerve injury.

MFG-E8 Ameliorates Nerve Injury-Induced Neuropathic Pain by Regulating Microglial Polarization and Neuroinflammation via Integrin β3/SOCS3/STAT3 Pathway in Mice.

Spinal microglial polarization plays a crucial role in the pathological processes of neuropathic pain following peripheral nerve injury. Accumulating evidence suggests that milk fat globule epidermal growth factor-8 (MFG-E8) exhibits anti-inflammatory effect and regulates microglial polarization through the integrin β3 receptor. However, the impact of MFG-E8 on microglial polarization in the context of neuropathic pain has not yet been investigated. In this study, we evaluated the effect of MFG-E8 on pain hypersensitivity and spinal microglial polarization following spared nerve injury (SNI) of the sciatic nerve in mice. We determined the molecular mechanisms underlying the effects of MFG-E8 on pain hypersensitivity and spinal microglial polarization using pain behavior assessment, western blot (WB) analysis, immunofluorescence (IF) staining, quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), and small interfering RNA (siRNA) transfection. Our findings indicate that SNI significantly increased the levels of MFG-E8 and integrin β3 expressed in microglia within the spinal cord of mice. Additionally, we observed that intrathecal injection of recombinant human MFG-E8 (rhMFG-E8) alleviated SNI induced-mechanical allodynia and thermal hyperalgesia. Furthermore, the results suggested that rhMFG-E8 facilitated M2 microglial polarization and ameliorated neuroinflammation via integrin β3/SOCS3/STAT3 pathway in the spinal cord of mice with SNI. Importantly, these effects were negated by integrin β3 siRNA, or SOCS3 siRNA. These results demonstrate that MFG-E8 ameliorates peripheral nerve injury induced-mechanical allodynia and thermal hyperalgesia by driving M2 microglial polarization and mitigating neuroinflammation mediated by integrin β3/SOCS3/STAT3 pathway in the spinal cord of mice. MFG-E8 may serve as a promising target for the treatment of neuropathic pain.

DOR activation in mature oligodendrocytes regulates α-ketoglutarate metabolism leading to enhanced remyelination in aged mice.

The decreased ability of mature oligodendrocytes to produce myelin negatively affects remyelination in demyelinating diseases and aging, but the underlying mechanisms are incompletely understood. In the present study, we identify a mature oligodendrocyte-enriched transcriptional coregulator diabetes- and obesity-related gene (DOR)/tumor protein p53-inducible nuclear protein 2 (TP53INP2), downregulated in demyelinated lesions of donors with multiple sclerosis and in aged oligodendrocyte-lineage cells. Dor ablation in mice of both sexes results in defective myelinogenesis and remyelination. Genomic occupancy in oligodendrocytes and transcriptome profiling of the optic nerves of wild-type and Dor conditional knockout mice reveal that DOR and SOX10 co-occupy enhancers of critical myelinogenesis-associated genes including Prr18, encoding an oligodendrocyte-enriched, proline-rich factor. We show that DOR targets regulatory elements of genes responsible for α-ketoglutarate biosynthesis in mature oligodendrocytes and is essential for α-ketoglutarate production and lipid biosynthesis. Supplementation with α-ketoglutarate restores oligodendrocyte-maturation defects in Dor-deficient adult mice and improves remyelination after lysolecithin-induced demyelination and cognitive function in 17-month-old wild-type mice. Our data suggest that activation of α-ketoglutarate metabolism in mature oligodendrocytes can promote myelin production during demyelination and aging.

Evaluation of the clinical effect of kangaroo-style intervention mode on neonatal cerebral palsy treated with mouse nerve growth factor

Evaluation of the clinical effect of kangaroo-style intervention mode on neonatal cerebral palsy treated with mouse nerve growth factor

Acute effect of gold nanoparticles on neuropathic pain in a model of regional complex pain syndrome

We evaluated the effects of gold nanoparticles (AuNPs) administered in the acute phase of an animal model of Complex Regional Pain Syndrome Type I (CRPS-I). Oxidative stress parameters [substances reactive to thiobarbituric acid (TBA-RS), total sulfhydryl content (SH), protein carbonyl content and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)] and pain, through mechanical and thermal allodynia, were evaluated in the blood and sciatic nerves of mice. Animals were anesthetized and an elastic tourniquet was used around the left hind paw for 120 minutes, followed by measurements of the mechanical threshold and thermal. Animals received intraperitoneal administrations of AuNPs at concentrations of 2.5 mg/L, 7.0 mg/L and 22.0 mg/L, Ankyrin Transient Potential Receptor 1 (TRPA1) antagonist (HC030031) or saline vehicle after induction of CRPS-I. AuNPs showed significant results in thermal and mechanical anti-allodynic effects on day 1 (2.5 mg/L), days 2 and 3 (7.0 and 22.0 mg/L). The TRPA1 reduced mechanical allodynia (days 1 and 2) and thermal allodynia (days 1, 2 and 3), in addition to reversing the changes caused by CRPS-I in oxidative stress. The CRPS-I model increased TBA-RS, reduced the total sulfhydryl content and increased CAT activity. The results showed that, at all concentrations, AuNPs reversed the increase in CAT. At 7.0 mg/L partially reversed and at 22.0 mg/L completely reversed the increase in TBA-RS levels and at 22.0 mg/L reversed the reduction in sulfhydryl content.

Respiratory pathology in the TDP-43 transgenic mouse model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that results in death within 2-5years of diagnosis. Respiratory failure is the most common cause of death in ALS. Mutations in the transactive response DNA binding protein 43 (TDP-43) encoded by the TARDBP gene are associated with abnormal cellular aggregates in neurons of patients with both familial and sporadic ALS. The role of these abnormal aggregates on breathing is unclear. Since respiratory failure is a major cause of death in ALS, we sought to determine the role of TDP-43 mutations on the respiratory motor unit in the Prp-hTDP-43A315T mouse model - a model that expresses human TDP-43 containing the A315T mutation. We assessed breathing using whole-body plethysmography, and investigated neuropathology in hypoglossal and phrenic respiratory motor units. Postmortem studies included quantification of hypoglossal and putative phrenic motor neurons, activated microglia and astrocytes in respiratory control centers, and assessment of hypoglossal and phrenic nerves of TDP43A315T mice. The male TDP43A315T mice display an early onset of rapid progression of disease, and premature death (less than 15weeks) compared to control mice and compared to female TDP43A315T mice who die between 20 and 35weeks of age. The TDP43A315T mice have progressive and profound breathing deficits at baseline and during a respiratory challenge. Histologically, hypoglossal and putative phrenic motor neurons of TDP43A315T mice are decreased and have increased microglial and astrocyte activation, indicating pronounced neurodegeneration and neuroinflammation. Further, there is axonopathy and demyelination in the hypoglossal and phrenic nerve of TDP43A315T mice. Thus, the TDP-43A315T mice have significant respiratory pathology and neuropathology, which makes them a useful translatable model for the study of novel therapies on breathing in ALS.

Genetic labeling of the nucleus of tractus solitarius neurons associated with electrical stimulation of the cervical or auricular vagus nerve in mice

IntroductionVagus nerve stimulation (VNS) is clinically useful for treating epilepsy, depression, and chronic pain. Currently, cervical VNS (cVNS) treatment is well-established, while auricular VNS (aVNS) is under development. Vagal stimulation regulates functions in diverse brain regions; therefore, it is critical to better understand how electrically-evoked vagal inputs following cVNS and aVNS engage with different brain regions. ObjectiveAs vagus inputs are predominantly transmitted to the nucleus of tractus solitarius (NTS), we directly compared the activation of NTS neurons by cVNS or aVNS and the brain regions directly projected by the activated NTS neurons in mice. MethodsWe adopted the targeted recombination in active populations method, which allows for the activity-dependent, tamoxifen-inducible expression of mCherry—a reporter protein—in neurons specifically associated with cVNS or aVNS. ResultscVNS and aVNS induced comparable bilateral mCherry expressions in neurons within the NTS, especially in its caudal section (cNTS). However, the numbers of mCherry-expressing neurons within different subdivisions of cNTS was distinctive. In both cVNS and aVNS, anterogradely labeled mCherry-expressing axonal terminals were similarly observed across different areas of the forebrain, midbrain, and hindbrain. These terminals were enriched in the rostral ventromedial medulla, parabrachial nucleus, periaqueductal gray, thalamic nuclei, central amygdala, and the hypothalamus. Sex difference of cVNS- and aVNS-induced labeling of NTS neurons was modest. ConclusionThe central projections of mCherry-expressing cNTS terminals are comparable between aVNS and cVNS, suggesting that cVNS and aVNS activate distinct but largely overlapping projections into the brain through the cNTS.

Sevoflurane impedes neuropathic pain by maintaining endoplasmic reticulum stress and oxidative stress homeostasis through inhibiting the activation of the PLCγ/CaMKII/IP3R signaling pathway.

To investigate the effect of sevoflurane on neuropathic pain induced by chronic constriction injury (CCI) of sciatic nerve in mice, and to elucidate its mechanism by animal experiments. Thirty-two C57BL/6 mice were randomly divided into four groups: Sham group, Model group, Control group and Sevoflurane group. First, a mouse model of neuropathic pain was established. Then, the mice in each group were killed on Day 14 after operation to harvest the enlarged lumbosacral spinal cord. In contrast with the Model group, the Sevoflurane group displayed a significantly increased paw withdrawal mechanical threshold (PWMT) and significantly prolonged paw withdrawal thermal latency (PWTL) from Day 5 after operation. The morphological changes of lumbosacral spinal cord were observed by hematoxylin-eosin (HE) staining and transmission electron microscopy. Pathological results showed that sevoflurane reduced nuclear pyknosis in lumbosacral spinal cord tissue, with a large number of mitochondrial crista disappearance and mitochondrial swelling. The results of Western blotting showed that sevoflurane significantly decreased the protein expressions of phosphorylated phospholipase Cγ (p-PLCγ), phosphorylated calcium/calmodulin-dependent protein kinase II (p-CaMKII) and phosphorylated inositol 1,4,5-triphosphate receptor (p-IP3R), and reduced the protein expressions of endoplasmic reticulum (ER) stress proteins glucose-regulated protein 78 (GRP78) and GRP94, oxidative stress-related proteins P22 and P47 and inflammatory factors nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), interleukin-1 β (IL-1β), and tumor necrosis factor-α (TNF-α). Sevoflurane inhibits neuropathic pain by maintaining ER stress and oxidative stress homeostasis through inhibiting the activation of the PLCγ/CaMKII/IP3R signaling pathway.