Dexmedetomidine Alleviates Microglia-Induced Spinal Inflammation and Hyperalgesia in Neonatal Rats by Systemic Lipopolysaccharide Exposure

Noxious stimulus and painful experience in early life can induce cognitive deficits and abnormal pain sensitivity. As a major component of the outer membrane of gram-negative bacteria, lipopolysaccharide (LPS) injection mimics clinical symptoms of bacterial infections. Spinal microglial activation and the production of pro-inflammatory cytokines have been implicated in the pathogenesis of LPS-induced hyperalgesia in neonatal rats. Dexmedetomidine (DEX) possesses potent anti-neuroinflammatory and neuroprotective properties through the inhibition of microglial activation and microglial polarization toward pro-inflammatory (M1) phenotype and has been widely used in pediatric clinical practice. However, little is known about the effects of DEX on LPS-induced spinal inflammation and hyperalgesia in neonates. Here, we investigated whether systemic LPS exposure has persistent effects on spinal inflammation and hyperalgesia in neonatal rats and explored the protective role of DEX in adverse effects caused by LPS injection. Systemic LPS injections induced acute mechanical hyperalgesia, increased levels of pro-inflammatory cytokines in serum, and short-term increased expressions of pro-inflammatory cytokines and M1 microglial markers in the spinal cord of neonatal rats. Pretreatment with DEX significantly decreased inflammation and alleviated mechanical hyperalgesia induced by LPS. The inhibition of M1 microglial polarization and microglial pro-inflammatory cytokines expression in the spinal cord may implicate its neuroprotective effect, which highlights a new therapeutic target in the treatment of infection-induced hyperalgesia in neonates and preterm infants.

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Phosphoglycerate Mutase 1 Prevents Neuronal Death from Ischemic Damage by Reducing Neuroinflammation in the Rabbit Spinal Cord

International Journal of Molecular Sciences ◽

10.3390/ijms21197425 ◽

2020 ◽

Vol 21 (19) ◽

pp. 7425

Author(s):

Hyo Young Jung ◽

Hyun Jung Kwon ◽

Woosuk Kim ◽

Kyu Ri Hahn ◽

Seung Myung Moon ◽

...

Keyword(s):

Oxidative Stress ◽

Spinal Cord ◽

Inflammatory Cytokines ◽

Neuronal Death ◽

Microglial Activation ◽

Ventral Horn ◽

Phosphoglycerate Mutase ◽

Ischemic Damage ◽

Tnf Α ◽

Pro Inflammatory Cytokines

Phosphoglycerate mutase 1 (PGAM1) is a glycolytic enzyme that increases glycolytic flux in the brain. In the present study, we examined the effects of PGAM1 in conditions of oxidative stress and ischemic damage in motor neuron-like (NSC34) cells and the rabbit spinal cord. A Tat-PGAM1 fusion protein was prepared to allow easy crossing of the blood-brain barrier, and Control-PGAM1 was synthesized without the Tat peptide protein transduction domain. Intracellular delivery of Tat-PGAM1, not Control-PGAM1, was achieved in a time- and concentration-dependent manner. Immunofluorescent staining confirmed the intracellular expression of Tat-PGAM1 in NSC34 cells. Tat-PGAM1, but not Control-PGAM1, significantly alleviated H2O2-induced oxidative stress, neuronal death, mitogen-activated protein kinase, and apoptosis-inducing factor expression in NSC34 cells. After ischemia induction in the spinal cord, Tat-PGAM1 treatment significantly improved ischemia-induced neurological impairments and ameliorated neuronal cell death in the ventral horn of the spinal cord 72 h after ischemia. Tat-PGAM1 treatment significantly mitigated the ischemia-induced increase in malondialdehyde and 8-iso-prostaglandin F2α production in the spinal cord. In addition, Tat-PGAM1, but not Control-PGAM1, significantly decreased microglial activation and secretion of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α induced by ischemia in the ventral horn of the spinal cord. These results suggest that Tat-PGAM1 can be used as a therapeutic agent to reduce spinal cord ischemia-induced neuronal damage by lowering the oxidative stress, microglial activation, and secretion of pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α.

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Decrease of IL-1β and TNF in the Spinal Cord Mediates Analgesia Produced by Ankle Joint Mobilization in Complete Freund Adjuvant-Induced Inflammation Mice Model

Frontiers in Physiology ◽

10.3389/fphys.2021.816624 ◽

2022 ◽

Vol 12 ◽

Author(s):

Carlos Minoru Omura ◽

Daniela Dero Lüdtke ◽

Verônica Vargas Horewicz ◽

Paula Franson Fernandes ◽

Taynah de Oliveira Galassi ◽

...

Keyword(s):

Spinal Cord ◽

Ankle Joint ◽

Inflammatory Cytokines ◽

Mechanical Hyperalgesia ◽

M2 Macrophages ◽

Macrophage Phenotype ◽

Mice Model ◽

Joint Mobilization ◽

Arginase 1 ◽

Pro Inflammatory Cytokines

ObjectiveThis study aims to investigate the effects of ankle joint mobilization (AJM) on mechanical hyperalgesia and peripheral and central inflammatory biomarkers after intraplantar (i.pl.) Complete Freund’s Adjuvant (CFA)-induced inflammation.MethodsMale Swiss mice were randomly assigned to 3 groups (n = 7): Saline/Sham, CFA/Sham, and CFA/AJM. Five AJM sessions were carried out at 6, 24, 48, 72, and 96 h after CFA injection. von Frey test was used to assess mechanical hyperalgesia. Tissues from paw skin, paw muscle and spinal cord were collected to measure pro-inflammatory (TNF, IL-1β) and anti-inflammatory cytokines (IL-4, IL-10, and TGF-β1) by ELISA. The macrophage phenotype at the inflammation site was evaluated by Western blotting assay using the Nitric Oxide Synthase 2 (NOS 2) and Arginase-1 immunocontent to identify M1 and M2 macrophages, respectively.ResultsOur results confirm a consistent analgesic effect of AJM following the second treatment session. AJM did not change cytokines levels at the inflammatory site, although it promoted a reduction in M2 macrophages. Also, there was a reduction in the levels of pro-inflammatory cytokines IL-1β and TNF in the spinal cord.ConclusionTaken together, the results confirm the anti-hyperalgesic effect of AJM and suggest a central neuroimmunomodulatory effect in a model of persistent inflammation targeting the pro-inflammatory cytokines IL-1β and TNF.

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Leucine rich repeats and calponin homology domain containing 1 inhibits microglia-mediated neuroinflammation in a rat traumatic spinal cord injury model

10.21203/rs.2.18899/v2 ◽

2020 ◽

Author(s):

Wen-Kai Chen ◽

Lin-Juan Feng ◽

Qiao-Dan Liu ◽

Qing-Feng Ke ◽

Pei-Ya Cai ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Inflammatory Cytokines ◽

Negative Regulator ◽

Mitogen Activated Protein Kinase ◽

Neuron Death ◽

Microglial Polarization ◽

Cord Injury ◽

Pro Inflammatory Cytokines

Abstract Background Spinal cord injury (SCI) triggers the primary mechanical injury and secondary inflammation-mediated injury. Neuroinflammation-mediated insult causes secondary and extensive neurological damage after SCI. Microglia play a pivotal role in the initiation and progression of post-SCI neuroinflammation. Methods To elucidate the significance of LRCH1 to microglial functions, we applied lentivirus-induced LRCH1 knockdown in primary microglia culture, and tested the role of LRCH1 in microglia-mediated inflammatory reaction both in vitro and in a rat SCI model. Results We found that LRCH1 was down-regulated in microglia after traumatic SCI. LRCH1 knockdown increased the production of pro-inflammatory cytokines such as IL-1β, TNF-α, and IL-6 after in vitro priming with lipopolysaccharide and adenosine triphosphate. Furthermore, LRCH1 knockdown promoted the priming-induced microglial polarization towards the pro-inflammatory inducible nitric oxide synthase (iNOS)-expressing microglia. LRCH1 knockdown also enhanced microglia-mediated N27 neuron death after priming. Further analysis revealed that LRCH1 knockdown increased priming-induced activation of p38 mitogen-activated protein kinase (MAPK) and Erk1/2 signaling, which are crucial to the inflammatory response of microglia. When LRCH1-knockdown microglia were adoptively injected into rat spinal cords, they enhanced post-SCI production of pro-inflammatory cytokines, increased SCI-induced recruitment of leukocytes, aggravated SCI-induced tissue damage and neuronal death, and worsened the locomotor function. Conclusion Our study reveals for the first time that LRCH1 serves as a negative regulator of microglia-mediated neuroinflammation after SCI, and provides clues for developing novel therapeutic approaches against SCI.

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Leucine rich repeats and calponin homology domain containing 1 inhibits microglia-mediated neuroinflammation in a rat traumatic spinal cord injury model

10.21203/rs.2.18899/v1 ◽

2019 ◽

Author(s):

Wen-Kai Chen ◽

Lin-Juan Feng ◽

Qiao-Dan Liu ◽

Qing-Feng Ke ◽

Pei-Ya Cai ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Inflammatory Cytokines ◽

Negative Regulator ◽

Mitogen Activated Protein Kinase ◽

Neuron Death ◽

Microglial Polarization ◽

Cord Injury ◽

Pro Inflammatory Cytokines

Abstract Background Spinal cord injury (SCI) triggers the primary mechanical injury and secondary inflammation-mediated injury. Neuroinflammation-mediated insult causes secondary and extensive neurological damage after SCI. Microglia play a pivotal role in the initiation and progression of post-SCI neuroinflammation.Methods To elucidate the significance of LRCH1 to microglial functions, we applied lentivirus-induced LRCH1 knockdown in primary microglia culture, and tested the role of LRCH1 in microglia-mediated inflammatory reaction both in vitro and in a rat SCI model.ResultsWe found that LRCH1 was down-regulated in microglia after traumatic SCI. LRCH1 knockdown increased the production of pro-inflammatory cytokines such as IL-1β, TNF-α, and IL-6 after in vitro priming with lipopolysaccharide and adenosine triphosphate. Furthermore, LRCH1 knockdown promoted the priming-induced microglial polarization towards the pro-inflammatory M1 type, as demonstrated by increased differentiation into inducible nitric oxide synthase (iNOS)+ microglia. LRCH1 knockdown also enhanced microglia-mediated N27 neuron death after priming. Further analysis revealed that LRCH1 knockdown increased priming-induced activation of p38 mitogen-activated protein kinase (MAPK) and Erk1/2 signaling, which are crucial for M1 polarization of microglia. When LRCH1-knockdown microglia were adoptively injected into rat spinal cords, they enhanced post-SCI production of pro-inflammatory cytokines, increased SCI-induced recruitment of leukocytes, aggravated SCI-induced tissue damage and neuronal death, and worsened the locomotor function.Conclusion Our study reveals for the first time that LRCH1 serves as a negative regulator of microglia-mediated neuroinflammation after SCI, and provides clues for developing novel therapeutic approaches against SCI.

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Human umbilical cord mesenchymal stem cell-derived extracellular vesicles attenuate experimental autoimmune encephalomyelitis via regulating pro and anti-inflammatory cytokines

Scientific Reports ◽

10.1038/s41598-021-91291-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Samira Ahmadvand Koohsari ◽

Abdorrahim Absalan ◽

Davood Azadi

Keyword(s):

Spinal Cord ◽

Body Weight ◽

Extracellular Vesicles ◽

Inflammatory Cytokines ◽

Clinical Score ◽

Human Umbilical Cord ◽

Therapeutic Effects ◽

Leukocyte Infiltration ◽

Anti Inflammatory ◽

Pro Inflammatory Cytokines

AbstractThe therapeutic effects of mesenchymal stem cells-extracellular vesicles have been proved in many inflammatory animal models. In the current study, we aimed to investigate the effect of extracellular vesicles (EVs) derived from human umbilical cord-MSC (hUCSC-EV) on the clinical score and inflammatory/anti-inflammatory cytokines on the EAE mouse model. After induction of EAE in C57Bl/6 mice, they were treated intravenously with hUCSC-EV or vehicle. The clinical score and body weight of all mice was registered every day. On day 30, mice were sacrificed and splenocytes were isolated for cytokine assay by ELISA. Cytokine expression of pro-/anti-inflammatory cytokine by real-time PCR, leukocyte infiltration by hematoxylin and eosin (H&E) staining, and the percent of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) positive cells by immunohistochemistry were assessed in the spinal cord. Our results showed that hUCSC-EV-treated mice have lower maximum mean clinical score (MMCS), pro-inflammatory cytokines, and inflammatory score in comparison to the control mice. We also showed that hUCSC-EV administration significantly improved body weight and increased the anti-inflammatory cytokines and the frequency of Treg cells in the spleen. There was no significant difference in the percent of GFAP and MBP positive cells in the spinal cord of experimental groups. Finally, we suggest that intravenous administration of hUCSC-EV alleviate induce-EAE by reducing the pro-inflammatory cytokines, such as IL-17a, TNF-α, and IFN-γ, and increasing the anti-inflammatory cytokines, IL-4 and IL-10, and also decrease the leukocyte infiltration in a model of MS. It seems that EVs from hUC-MSCs have the same therapeutic effects similar to EVs from other sources of MSCs, such as adipose or bone marrow MSCs.

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Effects of early nerve repair on experimental brachial plexus injury in neonatal rats

Journal of Hand Surgery (European Volume) ◽

10.1177/1753193417732696 ◽

2017 ◽

Vol 43 (3) ◽

pp. 275-281 ◽

Cited By ~ 1

Author(s):

Gráinne Bourke ◽

Aleksandra M. McGrath ◽

Mikael Wiberg ◽

Lev N. Novikov

Keyword(s):

Spinal Cord ◽

Brachial Plexus ◽

Brachial Plexus Injury ◽

Neuroprotective Effect ◽

Nerve Repair ◽

Neonatal Rats ◽

Spinal Motoneurons ◽

Muscle Weight ◽

Retrograde Degeneration ◽

Dendritic Branches

Obstetrical brachial plexus injury refers to injury observed at the time of delivery, which may lead to major functional impairment in the upper limb. In this study, the neuroprotective effect of early nerve repair following complete brachial plexus injury in neonatal rats was examined. Brachial plexus injury induced 90% loss of spinal motoneurons and 70% decrease in biceps muscle weight at 28 days after injury. Retrograde degeneration in spinal cord was associated with decreased density of dendritic branches and presynaptic boutons and increased density of astrocytes and macrophages/microglial cells. Early repair of the injured brachial plexus significantly delayed retrograde degeneration of spinal motoneurons and reduced the degree of macrophage/microglial reaction but had no effect on muscle atrophy. The results demonstrate that early nerve repair of neonatal brachial plexus injury could promote survival of injured motoneurons and attenuate neuroinflammation in spinal cord.

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