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1.
Leptin is a multifunctional hormone produced by the ob gene and is secreted by adipocytes that regulate food intake and energy metabolism. Numerous studies demonstrated that leptin is a novel neuroprotective effector, however, the mechanisms are largely unknown. Herein, we demonstrate the protective activities of leptin after ischemic stroke and provide the first evidence for the involvement of the connexin 43 (Cx43) in leptin-mediated neuroprotection. We found that leptin treatment reduces the infarct volume, improves animal behavioral parameters, and inhibits the elevation of Cx43 expression in vivo. In vitro, leptin reverses ischemia-induced SY5Y and U87 cells Cx43 elevation, secreted glutamate levels in medium and SY5Y cell death, these roles could be abolished by leptin receptor blocker. Additionally, leptin administration upregulated the extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation. Moreover, ERK1/2 inhibitors pretreatment reversed the effects of leptin on Cx43 expression, glutamate levels and cell apoptosis. In conclusion, the present study demonstrated that leptin can reduce the Cx43 expression and cell death both in vivo and in vitro via ERK1/2 signaling pathway. This result provides a novel regulatory signaling pathway of the neuroprotective effects of leptin and may contribute to ischemic brain injury prevention and therapy.  相似文献   

2.
Perampanel is a novel α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist, approved in over 35 countries as an adjunctive therapy for the treatment of seizures. Recently, it was found to exert protective effects against ischemic neuronal injury in vitro. In the present study, we investigated the potential protective effects of perampanel in a traumatic brain injury (TBI) model in rats. Oral administration with perampanel at a dose of 5 mg/kg exerted no major organ-related toxicities. We found that perampanel significantly attenuated TBI-induced brain edema, brain contusion volume, and gross motor dysfunction. The results of Morris water maze test demonstrated that perampanel treatment also improved cognitive function after TBI. These neuroprotective effects were accompanied by reduced neuronal apoptosis, as evidenced by decreased TUNEL-positive cells in brain sections. Moreover, perampanel markedly inhibited lipid peroxidation and obviously preserved the endogenous antioxidant system after TBI. In addition, enzyme-linked immunosorbent assay (ELISA) was performed at 4 and 24 h after TBI to evaluate the expression of inflammatory cytokines. The results showed that perampanel suppressed the expression of pro-inflammatory cytokines TNF-α and IL-1β, whereas increased the levels of anti-inflammatory cytokines IL-10 and TGF-β1. These data show that the orally active AMPAR antagonist perampanel affords protection against TBI-induced neuronal damage and neurological dysfunction through anti-oxidative and anti-inflammatory activity.  相似文献   

3.
Traumatic brain injury (TBI) triggers a series of neuroinflammatory processes that contribute to evolution of neuronal injury. The present study investigated the neuroprotective effects and anti-inflammatory actions of berberine, an isoquinoline alkaloid, in both in vitro and in vivo TBI models. Mice subjected to controlled cortical impact injury were injected with berberine (10 mg·kg−1) or vehicle 10 min after injury. In addition to behavioral studies and histology analysis, blood-brain barrier (BBB) permeability and brain water content were determined. Expression of PI3K/Akt and Erk signaling and inflammatory mediators were also analyzed. The protective effect of berberine was also investigated in cultured neurons either subjected to stretch injury or exposed to conditioned media with activated microglia. Berberine significantly attenuated functional deficits and brain damage associated with TBI up to day 28 post-injury. Berberine also reduced neuronal death, apoptosis, BBB permeability, and brain edema at day 1 post-injury. These changes coincided with a marked reduction in leukocyte infiltration, microglial activation, matrix metalloproteinase-9 activity, and expression of inflammatory mediators. Berberine had no effect on Akt or Erk 1/2 phosphorylation. In mixed glial cultures, berberine reduced TLR4/MyD88/NF-κB signaling. Berberine also attenuated neuronal death induced by microglial conditioned media; however, it did not directly protect cultured neurons subjected to stretch injury. Moreover, administration of berberine at 3 h post-injury also reduced TBI-induced neuronal damage, apoptosis and inflammation in vivo. Berberine reduces TBI-induced brain damage by limiting the production of inflammatory mediators by glial cells, rather than by a direct neuroprotective effect.  相似文献   

4.
Accumulating evidence indicates that autophagy and inflammatory responses contributes to secondary brain injury after traumatic brain injury (TBI), and toll-like receptor 4 (TLR4) is considered to involvement of this cascade and plays an important role. The present study was designed to determine the hypothesis that administration of resatorvid (TAK-242), a TLR4 antagonist, might provide a neuroprotective effect by inhibit TLR4-mediated pathway in a TBI rat model. Rat subjected to controlled cortical impact injury were injected with TAK-242 (0.5 mg/kg, i.v. injected) 10 min prior to injury. The results demonstrated that TAK-242 treatment significantly attenuated TBI-induced neurons loss, brain edema, and neurobehavioral impairment in rats. Immunoblotting analysis showed that TAK-242 treatment reduced TBI-induced TLR4, Beclin 1, and LC3-II levels, and maintained p62 levels at 24 h. Double immunolabeling demonstrated that LC3 dots co-localized with the hippocampus pyramidal neurons, and TLR4 was localized with the hippocampus neurons and astrocytes. In addition, the expression of TLR4 downstream signaling molecules, including MyD88, TRIF, NF-κB, TNF-α, and IL-1β, was significantly downregulated in hippocampus tissue by Western blot analysis. In conclusion, our findings indicate that pre-injury treatment with TAK-242 could inhibit neuronal autophagy and neuroinflammation responses in the hippocampus in a rat model of TBI. The neuroprotective effects of TAK-242 may be related to modulation of the TLR4-MyD88/TRIF-NF-κB signaling pathway. Furthermore, the study also suggests that TAK-242, an attractive potential drug, may be a promising drug candidate for TBI.  相似文献   

5.
Toll-like receptor 4 (TLR4) has been linked to various pathophysiological conditions, such as traumatic brain injury (TBI). It is reported that posttraumatic neuroinflammation is an essential event in the progression of brain injury after TBI. Recent evidences indicate that TLR4 mediates glial phagocytic activity and inflammatory cytokines production. Thus, TLR4 may be an important therapeutic target for neuroinflammatory injury post-TBI. This study was designed to explore potential effects and underlying mechanisms of TLR4 in rats suffered from TBI. TBI model was induced using a controlled cortical impact in rats, and application of TLR4 shRNA silenced TLR4 expression in brain prior to TBI induction. Elevated TLR4 was specifically observed in the hippocampal astrocytes and neurons posttrauma. Interestingly, TLR4 shRNA decreased the concentrations of interleukin (IL)-1β, IL-6, and tissue necrosis factor-α; alleviated hippocampal neuronal damage; reduced brain edema formation; and improved neurological deficits after TBI. Meanwhile, to further explore underlying molecular mechanisms of this neuroprotective effects of TLR4 knockdown, our results showed that TLR4 knockdown significantly inhibited the upregulation of autophagy-associated proteins caused by TBI. More importantly, an autophagy inducer, rapamycin pretreated, could partially abolish neuroprotective effects of TLR4 knockdown on TBI rats. Furthermore, TLR4 silencing markedly suppressed GFAP upregulation and improved cell hypertrophy to attenuate TBI-induced astrocyte activation. Taken together, these findings suggested that TLR4 knockdown ameliorated neuroinflammatory response and brain injury after TBI through suppressing autophagy induction and astrocyte activation.  相似文献   

6.
Breviscapine (BVP) has been widely used in the treatment of several systemic diseases, including those of the cardiovascular and cerebrovascular systems. But, few studies have looked at the neuroprotective effects of BVP and its potential effect in treating traumatic brain injury (TBI). The present study investigated the neuroprotective effect of BVP following TBI and illuminated the underlying mechanism. The weight drop-induced closed diffuse traumatic brain injury method was used to induce TBI in rats. BVP was injected intraperitoneally 30 minutes after TBI. Neurologic scores were performed to measure behavioral outcomes. Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays were performed on histopathologic tissue sections to evaluate neuronal apoptosis. The nuclear factor erythroid 2-related factor 2 (Nrf2) and its related downstream proteins, including heme oxygenase-1 (HO-1) and quinine oxidoreductase-1 (NQO1) were detected with Western blots. BVP treatment alleviated or attenuated TBI-induced neuron cell apoptosis and improved neurobehavioral functions through the upregulated expression of Nrf2 and its related downstream proteins. This study, using the drug, BVP, we present new mechanisms responsible for neuronal apoptosis in TBI with possible involvement of the Nrf2 pathway.  相似文献   

7.
Brain edema is a major traumatic brain injury (TBI)-related neurological complication. In the initiation stage of TBI, brain edema is characterized by astrocyte swelling (cytotoxic edema). We studied the impact of a long noncoding RNA, Malat1, on the TBI-induced astrocyte swelling and brain edema. Our results showed that Malat1 was downregulated in both the TBI rat model and the astrocyte fluid percussion injury (FPI) model, which concurred with brain edema and astrocyte swelling. Overexpression of Malat1 significantly inhibited rat brain edema, meanwhile reducing interleukin-6 (IL-6), nuclear factor-κB (NF-κB), and aquaporin 4 (AQP4) expression after TBI. In addition, overexpression of Malat1 ameliorated FPI-induced astrocyte swelling and reduced IL-6 release. Quantitative real-time polymerase chain reaction and Western blot analysis also corroborated the inhibitory effects of Malat1 on NF-κB and AQP4 expression after FPI. Our results highlighted the protective effects of Malat1 on the TBI-induced brain edema, which were mediated through regulating IL-6, NF-κB, and AQP4 expression. Our study could provide a novel approach for TBI treatment.  相似文献   

8.
Cognitive deficits in survivors of traumatic brain injury (TBI) are associated with irreversible neurodegeneration in brain regions such as the hippocampus. Comparative gene expression analysis of dying and surviving neurons could provide insight into potential therapeutic targets. We used two pathway-specific PCR arrays (RT2 Profiler Apoptosis and Neurotrophins & Receptors PCR arrays) to identify and validate TBI-induced gene expression in dying (Fluoro-Jade-positive) or surviving (Fluoro-Jade- negative) pyramidal neurons obtained by laser capture microdissection (LCM). In the Apoptosis PCR array, dying neurons showed significant increases in expression of genes associated with cell death, inflammation, and endoplasmic reticulum (ER) stress compared with adjacent, surviving neurons. Pro-survival genes with pleiotropic functions were also significantly increased in dying neurons compared to surviving neurons, suggesting that even irreversibly injured neurons are able to mount a protective response. In the Neurotrophins & Receptors PCR array, which consists of genes that are normally expected to be expressed in both groups of hippocampal neurons, only a few genes were expressed at significantly different levels between dying and surviving neurons. Immunohistochemical analysis of selected, differentially expressed proteins supported the gene expression data. This is the first demonstration of pathway-focused PCR array profiling of identified populations of dying and surviving neurons in the brain after TBI. Combining precise laser microdissection of identifiable cells with pathway-focused PCR array analysis is a practical, low-cost alternative to microarrays that provided insight into neuroprotective signals that could be therapeutically targeted to ameliorate TBI-induced neurodegeneration.  相似文献   

9.
Hydrogen sulfide (H2S), a novel gaseous mediator, has been recognized as an important neuromodulator and neuroprotective agent in the central nervous system. The present study was undertaken to study the effects of exogenous H2S on traumatic brain injury (TBI) and the underlying mechanisms. The effects of exogenous H2S on TBI were examined by using measurement of brain edema, behavior assessment, propidium iodide (PI) staining, and Western blotting, respectively. Compared to TBI groups, H2S pretreatment had reduced brain edema, improved motor performance and ameliorated performance in Morris water maze test after TBI. Immunoblotting results showed that H2S pretreatment reversed TBI-induced cleavage of caspase-3 and decline of Bcl-2, suppressed LC3-II, Beclin-1 and Vps34 activation and maintained p62 level in injured cortex and hippocampus post TBI. The results suggest a protective effect and therapeutic potential of H2S in the treatment of brain injury and the protective effect against TBI may be associated with regulating apoptosis and autophagy.  相似文献   

10.
Traumatic brain injury (TBI) results in neuronal apoptosis, autophagic cell death and necroptosis. Necroptosis is a newly discovered caspases-independent programmed necrosis pathway which can be triggered by activation of death receptor. Previous works identified that necrostatin-1 (NEC-1), a specific necroptosis inhibitor, could reduce tissue damage and functional impairment through inhibiting of necroptosis process following TBI. However, the role of NEC-1 on apoptosis and autophagy after TBI is still not very clear. In this study, the amount of TBI-induced neural cell deaths were counted by PI labeling method as previously described. The expression of autophagic pathway associated proteins (Beclin-1, LC3-II, and P62) and apoptotic pathway associated proteins (Bcl-2 and caspase-3) were also respectively assessed by immunoblotting. The data showed that mice pretreated with NEC-1 reduced the amount of PI-positive cells from 12 to 48?h after TBI. Immunoblotting results showed that NEC-1 suppressed TBI-induced Beclin-1 and LC3-II activation which maintained p62 at high level. NEC-1 pretreatment also reversed TBI-induced Bcl-2 expression and caspase-3 activation, as well as the ratio of Beclin-1/Bcl-2. Both 3-MA and NEC-1 suppressed TBI-induced caspase-3 activation and LC3-II formation, Z-VAD only inhibited caspase-3 activation but increased LC3-II expression at 24?h post-TBI. All these results revealed that multiple cell death pathways participated in the development of TBI, and NEC-1 inhibited apoptosis and autophagy simultaneously. These coactions may further explain how can NEC-1 reduce TBI-induced tissue damage and functional deficits and reflect the interrelationship among necrosis, apoptosis and autophagy.  相似文献   

11.
It has been suggested that oxidative stress plays an important role in the pathophysiology of traumatic brain injury (TBI). N-acetylcysteine (NAC) and selenium (Se) display neuroprotective activities mediated at least in part by their antioxidant and anti-inflammatory properties although there is no report on oxidative stress, antioxidant vitamin, interleukin-1 beta (IL)-1β and IL-4 levels in brain and blood of TBI-induced rats. We investigated effects of NAC and Se administration on physical injury-induced brain toxicity in rats. Thirty-six male Sprague–Dawley rats were equally divided into four groups. First and second groups were used as control and TBI groups, respectively. NAC and Se were administrated to rats constituting third and forth groups at 1, 24, 48 and 72 h after TBI induction, respectively. At the end of 72 h, plasma, erythrocytes and brain cortex samples were taken. TBI resulted in significant increase in brain cortex, erythrocytes and plasma lipid peroxidation, total oxidant status (TOS) in brain cortex, and plasma IL-1β values although brain cortex vitamin A, β-carotene, vitamin C, vitamin E, reduced glutathione (GSH) and total antioxidant status (TAS) values, and plasma vitamin E concentrations, plasma IL-4 level and brain cortex and erythrocyte glutathione peroxidase (GSH-Px) activities decreased by TBI. The lipid peroxidation and IL-1β values were decreased by NAC and Se treatments. Plasma IL-4, brain cortex GSH, TAS, vitamin C and vitamin E values were increased by NAC and Se treatments although the brain cortex vitamin A and erythrocyte GSH-Px values were increased through NAC only. In conclusion, NAC and Se caused protective effects on the TBI-induced oxidative brain injury and interleukin production by inhibiting free radical production, regulation of cytokine-dependent processes and supporting antioxidant redox system.  相似文献   

12.

Background

Traumatic brain injury (TBI) initiates a neuroinflammatory cascade that contributes to neuronal damage and behavioral impairment. Toll-like receptors (TLRs) are signaling receptors in the innate immune system, although emerging evidence indicates their role in brain injury. We have therefore investigated the role played by TLR4 signaling pathway in the development of mechanisms of secondary inflammatory process in traumatic brain injury (TBI) differ in mice that lack a functional TLR4 signaling pathway.

Methods/Principal Findings

Controlled cortical impact injury was performed on TLR4 knockout (KO) mice (C57BL/10ScNJ) and wild-type (WT) mice (C57BL/10ScNJ). TBI outcome was evaluated by determination of infarct volume and assessment of neurological scores. Brains were collected at 24 h after TBI. When compared to WT mice, TLR4 KO mice had lower infarct volumes and better outcomes in neurological and behavioral tests (evaluated by EBST and rotarod test). Mice that lacked TLR4 had minor expression of TBI-induced GFAP, Chymase, Tryptase, IL-1β, iNOS, PARP and Nitrotyrosine mediators implicated in brain damage. The translocation of expression of p-JNK, IκB-α and NF-κB pathway were also lower in brains from TLR4 KO mice. When compared to WT mice, resulted in significant augmentation of all the above described parameters. In addition, apoptosis levels in TLR4 KO mice had minor expression of Bax while on the contrary with Bcl-2.

Conclusions/Significance

Our results clearly demonstrated that absence of TLR4 reduces the development of neuroinflammation, tissues injury events associated with brain trauma and may play a neuroprotective role in TBI in mice.  相似文献   

13.
14.
Chen T  Cao L  Dong W  Luo P  Liu W  Qu Y  Fei Z 《Neurochemical research》2012,37(5):983-990
Several previous studies utilizing selective pharmacological antagonists have demonstrated that type 5 metabotropic glutamate receptors (mGluR5) are potential therapeutic targets for the treatment of numerous disorders of the central nervous system, but the role of mGluR5 activation in traumatic brain injury (TBI) is not fully understood. Here in an in vitro TBI model, the mGluR5 agonist (RS)-2-chloro-5- hydroxyphenylglycine (CHPG) and the positive allosteric modulators 3-cyano-N-(1,3- diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB) were used to investigate the neuroprotective potency of mGluR5 activation. Data showed that CHPG and CDPPB suppressed the increase of LDH release and caspase-3 activation induced by traumatic neuronal injury in a dose-dependent manner, and the salutary effects were also present when these compounds were added 1 h after injury. Western blot was used to examine the activation of three members of mitogen-activated protein kinases: extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 kinase (p38). CHPG and CDPPB enhanced the activation of ERK after traumatic neuronal injury, and PD98059 and U0126, two selective MEK/ERK inhibitors, partly revised the protective effects. Furthermore, we also investigated the role of protein kinase C (PKC) in CHPG and CDPPB-induced neuroprotection. With the pretreatment of chelerythrine chloride, a PKC inhibitor, the surpressing effects of CHPG and CDPPB on traumatic injury-evoked LDH release and caspase-3 activation were blocked. All of these findings extended the protective role of mGluR5 activation in an in vitro model of TBI and suggested that these protective effects might be mediated by the PKC-dependent activation of MEK/ERK pathway. These results may have important implications for the development of mGluR5 modulators to treat TBI.  相似文献   

15.
P Luo  T Chen  Y Zhao  L Zhang  Y Yang  W Liu  S Li  W Rao  S Dai  J Yang  Z Fei 《Cell death & disease》2014,5(4):e1174
Traumatic brain injury (TBI) produces excessive glutamate, leading to excitotoxicity via the activation of glutamate receptors. Postsynaptic density scaffold proteins have crucial roles in mediating signal transduction from glutamate receptors to their downstream mediators. Therefore, studies on the mechanisms underlying regulation of excitotoxicity by scaffold proteins can uncover new treatments for TBI. Here, we demonstrated that the postsynaptic scaffold protein Homer 1a was neuroprotective against TBI in vitro and in vivo, and this neuroprotection was associated with its effects on group I metabotropic glutamate receptors (mGluRs). Upon further study, we found that Homer 1a mainly affected neuronal injury induced by mGluR1 activation after TBI and also influenced mGluR5 function when its activity was restored. The ability of Homer 1a to disrupt mGluR-ERK signaling contributed to its ability to regulate the functions of mGluR1 and mGluR5 after traumatic injury. Intracellular Ca2+ and PKC were two important factors involved in the mediation of mGluR-ERK signaling by Homer 1a. These results define Homer 1a as a novel endogenous neuroprotective agent against TBI.  相似文献   

16.
Experimental studies have demonstrated significant secondary damage (including cell apoptosis, blood–brain barrier disruption, inflammatory responses, excitotoxic damage, and free radical production) after traumatic brain injury (TBI). Quercetin is a natural flavonoid found in high quantities in fruits and vegetables, and may be a potential antioxidant and free radical scavenger. The purpose of this study was to determine the effects of quercetin on TBI-induced upregulation of oxidative stress, inflammation, and apoptosis in adult Sprague–Dawley rats. Animals were subjected to Feeney’s weight-drop injury, thus inducing the parietal contusion brain injury model. Quercetin was administered (30 mg/kg intraperitoneal injection) 0, 24, 48, and 72 h after TBI. Quercetin reduced cognitive deficits, the number of TUNEL- and ED-1-positive cells, the protein expressions of Bax and cleaved-caspase-3 proteins, and the levels of TBARS and proinflammatory cytokines, and increased the activity of antioxidant enzymes (GSH-Px, SOD, and CAT) at 1 week after TBI. Our results suggest that in TBI rats, quercetin improves cognitive function owing to its neuroprotective action via the inhibition of oxidative stress, leading to a reduced inflammatory response, thereby reducing neuronal death.  相似文献   

17.
Tetramethylpyrazine (TMP) has been widely used in China as a drug for the treatment of various diseases. Recent studies have suggested that TMP has a protective effect on ischemic neuronal damage. However, the exact mechanism is still unclear. This study aims to investigate the mechanism of TMP mediated ischemic hippocampal neurons injury induced by oxygen-glucose deprivation (OGD). The effect of TMP on hippocampal neurons viability was detected by MTT assay, LDH release assay and apoptosis rate was measured by flow cytometry. TMP significantly suppressed neuron apoptosis in a concentration-dependent manner. TMP could significantly reduce the elevated levels of connexin32 (Cx32) induced by OGD. Knockdown of Cx32 by siRNA attenuated OGD injury. Moreover, our study showed that viability was increased in siRNA-Cx32-treated-neurons, and neuron apoptosis was suppressed by activating Bcl-2 expression and inhibiting Bax expression. Over expression of Cx32 could decrease neurons viability and increase LDH release. Furthermore, OGD increased phosphorylation of ERK1/2 and p38, whose inhibitors relieved the neuron injury and Cx32 up-regulation. Taken together, TMP can reverse the OGD-induced Cx32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathways.  相似文献   

18.
19.
Blood‐brain barrier (BBB) disruption and neuronal apoptosis are important pathophysiological processes after traumatic brain injury (TBI). In clinical stroke, Dl‐3n‐butylphthalide (Dl‐NBP) has a neuroprotective effect with anti‐inflammatory, anti‐oxidative, anti‐apoptotic and mitochondrion‐protective functions. However, the effect and molecular mechanism of Dl‐NBP for TBI need to be further investigated. Here, we had used an animal model of TBI and SH‐SY5Y/human brain microvascular endothelial cells to explore it. We found that Dl‐NBP administration exerts a neuroprotective effect in TBI/OGD and BBB disorder, which up‐regulates the expression of tight junction proteins and promotes neuronal survival via inhibiting mitochondrial apoptosis. The expressions of autophagy‐related proteins, including ATG7, Beclin1 and LC3II, were significantly increased after TBI/OGD, and which were reversed by Dl‐NBP treatment both in vivo and in vitro. Moreover, rapamycin treatment had abolished the effect of Dl‐NBP for TBI recovery. Collectively, our current studies indicate that Dl‐NBP treatment improved locomotor functional recovery after TBI by inhibiting the activation of autophagy and consequently blocking the junction protein loss and neuronal apoptosis. Dl‐NBP, as an anti‐inflammatory and anti‐oxidative drug, may act as an effective strategy for TBI recovery.  相似文献   

20.
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