Curcumin modulates TLR4/NF-κB inflammatory signaling pathway following traumatic spinal cord injury in rats

Abstract

Background

Curcumin, a polyphenolic compound extracted from the plant turmeric, has protective effects on spinal cord injury (SCI) through attenuation of inflammatory response. This study was designed to detect whether curcumin modulates toll-like receptor 4 (TLR4) and the nuclear factor-kappa B (NF-κB) inflammatory signaling pathway in the injured rat spinal cord following SCI.

Methods

Adult male Sprague–Dawley rats were subjected to laminectomy at T8–T9 and compression with a vascular clip. There were three groups: (a) sham group; (b) SCI group; and (g) SCI + curcumin group. We measured TLR4 gene and protein expression by real-time polymerase chain reaction and western blot analysis; NF-κB activity by electrophoretic mobility shift assay, inflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 levels by enzyme-linked immunosorbent assay, hindlimb locomotion function by Basso, Beattie, and Bresnahan rating, spinal cord edema by wet/dry weight method, and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) analysis.

Results

The results showed that SCI induced the up-regulation of TLR4, NF-κB, and inflammatory cytokines in the injured rat spinal cord. Treatment with curcumin following SCI markedly down-regulated the levels of these agents related to the TLR4/NF-κB inflammatory signaling pathway. Administration of curcumin also significantly ameliorated SCI induced hind limb locomotion deficits, spinal cord edema, and apoptosis.

Conclusions

Post-SCI curcumin administration attenuates the TLR4/NF-κB inflammatory signaling pathway in the injured spinal cord, and this may be a mechanism whereby curcumin improves the outcome following SCI.     

Exogenous administration of PACAP alleviates traumatic brain injury in rats through a mechanism involving the TLR4/MyD88/NF-κB pathway

Pituitary adenylate cyclase-activating polypeptide (PACAP) is effective in reducing axonal damage associated with traumatic brain injury (TBI), and has immunomodulatory properties. Toll-like receptor 4 (TLR4) is an important mediator of the innate immune response. It significantly contributes to neuroinflammation induced by brain injury. However, it remains unknown whether exogenous PACAP can modulate TBI through the TLR4/adapter protein myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway. In this study, we investigated the potential neuroprotective mechanisms of PACAP pretreatment in a weight-drop model of TBI. PACAP38 was microinjected intracerebroventricularly before TBI. Brain samples were extracted from the pericontusional area in the cortex and hippocampus. We found that TBI induced significant upregulation of TLR4, with peak expression occurring 24?h post-trauma, and that pretreatment with PACAP significantly improved motor and cognitive dysfunction, attenuated neuronal apoptosis, and decreased brain edema. Pretreatment with PACAP inhibited upregulation of TLR4 and its downstream signaling molecules MyD88, p-IκB, and NF-κB, and suppressed increases in the levels of the downstream inflammatory agents interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), in the brain tissue around the injured cortex and in the hippocampus. Administration of PACAP both in vitro and in vivo attenuated the ability of the TLR4 agonist lipopolysaccharide (LPS) to increase TLR4 protein levels. Therefore, PACAP exerts a neuroprotective effect in this rat model of TBI, by inhibiting a secondary inflammatory response mediated by the TLR4/MyD88/NF-κB signaling pathway in microglia and neurons, thereby reducing neuronal death and improving the outcome following TBI.     

Uric acid induces inflammatory injury in HK-2 cells via PI3K/AKT/NF-κB signaling pathway

Objective To investigate the effects and underlying mechanisms of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/NF-κB signaling pathway in human kidney-2 (HK-2) cells of hyperuricemic nephropathy. Methods HK-2 cells were cultured in vitro and randomly divided into control group and experimental group. The experimental group was induced by high uric acid (720 μmol/L) immersion for 48 h to establish a cell model of hyperuricemic nephropathy in vitro and subsequently divided into hyperuricemic group, overexpressed protease activated receptor 2 (PAR2) and knockdown PAR2 group. The expressions of PAR2, PI3K, AKT, NF-κB mRNA were measured by real-time PCR. The expressions of PAR2, PI3K, AKT and NF-κB protein were measured by Western blotting. The expressions of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), pro-interleukin-1β (pro-IL-1β), interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) were detected by enzyme linked immunosorbent assay (ELISA). Results (1) Compared with the control group, the expressions of PAR2, PI3K, AKT and NF-κB mRNA and protein in hyperuricemic group were significantly increased (all P＜0.05), the expressions of TNF-α, MCP-1, IL-6, pro-IL-1β, IL-1β and TGF-β1 in the supernatant in hyperuricemic group were significantly increased (all P＜0.01). (2) Compared with the hyperuricemic group, the expressions of PAR2, PI3K, AKT and NF-κB mRNA and protein in overexpressed PAR2 group were significantly increased (all P＜0.05), the expressions of TNF-α, MCP-1, IL-6, IL-1β and TGF-β1 in the supernatant were significantly increased (all P＜0.05). (3) Compared with the hyperuricemic group, the expression of PAR2, PI3K, AKT and NF-κB mRNA and protein in knockdown PAR2 group were significantly decreased (all P＜0.05), the expressions of IL-6, pro-IL-1β, IL-1β and TGF-β1 in the supernatant were significantly decreased (all P＜0.05). Conclusions In the process of uric acid-induced HK-2 cell damage, uric acid significantly up-regulates the expression of PI3K/AKT/NF-κB signaling pathway by activating PAR2, leading to a marked increase in inflammatory damage. Knocking down PAR2 inhibits the expression of PI3K/AKT/NF-κB signaling pathway, which can effectively reduce the inflammatory damage of HK-2 cells.     

Antioxidation of quercetin against spinal cord injury in rats

Objective : To observe the effect of quercetin on experimental spinal cord injury (SCI) in rats. Methods: Sixty Sprague-Dawley rats were randomly divided into four groups : Group A only for laminectomy, Group B for laminectomy with SCI, Group C for SCI and intraperitoneal injection with a bolus of 200 mg/kg quercetin and Group D for SCI and intraperitoneal injection of saline. SCI model was made by using modified Aliens method on T12. Six rats of each group were killed at 4 h after injury and the levels of free iron and malondialdehyde ( MDA) of the involved spinal cord segments were measured by bleomycin and thiobarbituric acid (TBA) assays separately. The recovery of hind limb function was assessed by Modified Tarlov 's scale and inclined plane method at 7 d,14 d and 21 d after SCI. The histological changes of the damaged spinal cord were also examined at 7 d after SCI. Results: After SCI, the levels of free iron and MDA were significantly increased in Groups B and D, while not in Group C. The Modified Tarlov 's score and the inclined plane angles were significantly decreased in Groups B, C and D. The histological findings were not improved. Conclusions: After SCI, quercetin can reduce the level of lipid peroxidation, but not improve recovery of function.     

Blockade of Indoleamine 2,3-Dioxygenase attenuates lipopolysaccharide-induced kidney injury by inhibiting TLR4/NF-κB signaling

Clinical and Experimental Nephrology - Blockade of indoleamine 2,3-dioxygenase (IDO) has been shown to alleviate lipopolysaccharide (LPS)-induced endotoxic shock and reduce sepsis mortality, but...     

Effects of recombinant sCRl on the immune inflammatory reaction in acute spinal cord injury tissue of rats

OBJECTIVE: To determine the effects of recombinant soluble complement receptor type I (sCR1) on the immune inflammatory reaction in acute spinal cord injury tissue of rats and its protective effects. METHODS: SD rat models of acute spinal cord injury were prepared by modified Allen's method. The motor function of the rat lower extremities in sCR1 group and normal saline (NS) group was evaluated by the tiltboard experiment at 12 h, 1 d, 3 d, 7 d, and 14 d. The neutrophil infiltration and C3c positive expression were observed. The myeloperoxidase activity was assessed in the injury tissue at 12 h, 1 d, 3 d, 7 d, and 14 d after injury in the two groups. RESULTS: The motor function of rat in sCR1 group at 3 d, 7 d, and 14 d was obviously better than that in NS group (P<0.01, P<0.01, P<0.01). C3c positive expression in sCR1 group at each time point after injury was obviously less than that in NS group (P<0.01). The myeloperoxidase activity in sCR1 group at each time point after injury was obviously less than that in NS group (P<0.01). CONCLUSIONS: Recombinant soluble complement receptor type I (sCR1) can lessen the immune inflammatory reaction in acute spinal cord injury tissue and relieve secondary spinal cord injury by inhibiting the activation of the complement system.     

Effects of recombinant sCR1 on the immune inflammatory reaction in acute spinal cord injury tissue of rats

cutespinalcordinjuryisaseverekindoftrauma.Thesecondaryinjurymechanismhasbeentoocomplextobetotallyunderstoodtillnow .Studieshaveshownthattheimmuneinflammatoryreactionparticipatesinsecondaryspinalcordinjuryasanimportantpathologicalprocessinearlyinjury .Itwa…     

Expression and effect of Caspase-3 in neurons after tractive spinal cord injury in rats

Thereisextensiveapoptosisafterinjuryofthecentralnervoussystem.Apoptosisisarathercomplicatedprocess,involvingwithsubtleregulationsofmacromolecules,likecellreceptor,adaptormolecule,proteaseandinhibitor.Among them,Caspaseproteasefamilyisthecoreinthe processo…     

Observation and establishment of an animal model of tractive spinal cord injury in rats

TDepartmentofOrthopaedics,WestChinaHospital,SichuanUniversity,Chengdu 6 10 0 4 1,China (LiuL ,ChiLT ,TuZQ ,ShengB ,ZhouZKandPeiFX)*Correspondingauthor :Tel:86 2 8 85 4 2 2 4 2 8,E mail:PeiFuxing @16 3.comractivespinalcordinjuryisoneofthecommoncomplicationsofspinalorthomorphia .WiththeappilcationofthreedimensionalinstrumentssuchasCD (cotreldubousse) ,TSRH (TexasScottishRiteHospital)etc .andmonitoringofevokedpotentialduringoperation ,1therangeofoperativeaccommodationsenlargescorr…     

Effect of nerve growth factor on neuronal apoptosis after spinal cord injury in rats

OBJECTIVE: To explore the molecular mechanism of the protective effect of nerve growth factor (NGF) on injured spinal cord. METHODS: The posterior T(8) (the 8th thoracic segment) spinal cords of 60 Wistar rats were injured by impacts caused by objects (weighing 10 g) falling from a height of 2.5 cm with Allen's way. Solution with nerve growth factors (NGF) was given to 30 rats (the NGF group) through a microtubule inserted into the subarachnoid cavity immediately, and at 2, 4, 8, 12 and 24 hours after spinal cord injury (SCI) respectively. Normal saline (NS) with same volume was given to the other 30 rats (the NS group) with the same method. And 5 normal rats were taken as the normal controls. The expression of bcl-2 and bax proteins in spinal cord was detected with immunohistochemistry. The apoptotic neurons in spinal cord were measured with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling of DNA fragments (TUNEL) staining. RESULTS: The positive expression of bcl-2 protein was strong in the normal controls, but decreased in the NS group, and increased significantly in the NGF group as compared with that of the NS group (P<0.01). The positive expression of bax protein was also strong in the normal controls, but increased in the NS group, and decreased significantly in the NGF group as compared with that of the NS group (P<0.01). Apoptotic neurons were found in the NS group, and they decreased significantly in the NGF group as compared with that of the NS group (P<0.01). CONCLUSIONS: NGF can protect the injured nerve tissues through stimulating the expression of bcl-2 protein, inhibiting the expression of bax protein and inhibiting the neuronal apoptosis after SCI.     

TLR4/NF-κB通路与骨质疏松症关系的研究进展

骨质疏松症(osteoporosis, OP)是一种普遍存在的与年龄相关的骨骼疾病,雌激素缺乏和衰老是主要病因,近年来越来越多的研究表明炎症反应在OP的发生发展过程中发挥重要作用。Toll样受体4(toll like receptor 4,TLR4)是Toll样受体家族的主要成员,是内毒素最重要的模式识别受体。TLR4是经典的炎症信号转导通路,当TLR4信号通路激活,与核因子κB (nuclear factorκB,NF-κB)转移到细胞核并释放炎性细胞因子(TNF-α、IL-1β、IL-6等),并抑制骨髓间充质干细胞成骨分化及钙盐沉积,促进破骨细胞成熟,最终导致OP。对TLR4信号通路与OP关系的研究不仅可以从炎症角度深入揭示OP的发病机制,还可以为OP的防治提供新的思路。     

Activation of NF-κB pathway in oral buccal mucosa during small intestinal ischemia-reperfusion injury

BackgroundIntestinal ischemia-reperfusion injury induces intestinal mucosal barrier disruption, systemic inflammatory response syndrome, multiorgan failure, and death. The major pathway for the systemic inflammatory responses depends on nuclear factor kappa B (NF-κB). However, direct measuring of NF-κB in injured tissues is not routinely available. Our aim was to determine whether NF-кB pathway in buccal mucosa is activated during intestinal ischemia-reperfusion injury.Materials and methodsMale Sprague-Dawley rats were prepared for the animal experiment. Superior mesenteric artery (SMA) was exposed and clamped for 30 min in the intestinal ischemia-reperfusion (IR) group. SMA was exposed only in control group. Serum, buccal mucosa, and small intestinal mucosa were harvested in 90 min after reperfusion in IR or 120 min after SMA exposure in control group. Serum cytokine levels and tissue NF-κB pathway activities were measured.ResultsSerum TNF-α (5.49 ± 2.72 versus 1.77 ± 1.20 pg/mL, P = 0.002) and interleukin-6 (232.32 ± 29.98 versus 115.92 ± 17.81 pg/mL, P = 0.002) levels were significantly higher in IR than control group. Intestinal mucosal cytoplasmic phosphorylated inhibitor kappa B (IκB)/IκB ratio, nuclear NF-κB expression, and NF-κB DNA-binding activity were significantly higher in IR than control group. Buccal mucosal cytoplasmic phosphorylated IκB/IκB ratio, nuclear NF-κB expression, and NF-κB DNA-binding activity were also higher in IR than control group.ConclusionBuccal mucosal NF-κB pathway was activated by intestinal ischemia-reperfusion injury. The present study suggests that buccal mucosal may be considered as an indicator for the assessment of intestinal ischemia-reperfusion injury.     

TLR4/NF-κB信号通路在脊髓损伤中的作用

[目的]探讨TLR4/NF-κB信号通路在急性脊髓损伤发病机制中的作用.[方法]SD大鼠随机分为假手术组、损伤组和单唾液酸神经节苷酯组(monosialoganglioside,GM1组).其中,前一组仅行假手术,后两组采用改良Allen法建立大鼠脊髓损伤模型.术后,GM1组给予静脉GM1,假手术组、损伤组静脉给予等量...     

Protective effect of liposome-mediated glial cell line. derived neurotrophic factor gene transfer in vivo on motoneurons following spinal cord injury in rats

IDepartmentofOrthopedicandSpineSurgery ,NanfangHospital,FirstMilitaryMedicalUniversity ,Guangzhou 5 10 5 15 ,China (LuKW ,ChenZYandHouTS) Correspondingauthor:Tel:86 2 0 6 136 0 0 4 6 ,E mail:lukaiwu @sohu .comThisworkwassupportedbyNationalNaturalScienceFoundationofChina (30 0 0 0 0 4 8)andtheNationalBasicResearchProgram (G 19990 5 4 0 0 0 )ofChina.nrecentyears ,substantialevidencehassuggestedthatearlyadministrationofexogenousneurotrophicfactors (NTFs)intoinjuredregioncanfacilit…     

Salvianolic acid B attenuates spinal cord ischemia-reperfusion–induced neuronal injury and oxidative stress by activating the extracellular signal–regulated kinase pathway in rats

Background

Salvianolic acid B (SalB), the main bioactive compound isolated from the traditional Chinese medicinal herb broad Radix Salviae Miltiorrhizae exerts a spectrum of pharmacologic activities. We investigated the effects of SalB treatment in a rat model of spinal cord ischemia and reperfusion (I/R) injury and the underlying mechanism.

Materials and methods

SalB was administered at 1, 10, or 50 mg/kg after spinal cord ischemia. The potential protective effects on spinal cord injury were determined by spinal cord edema, infarct volume, and motor function assessment of the hind limbs.

Results

SalB treatment significantly decreased spinal cord edema and infarct volume and preserved motor function of the hind limbs in a dose-dependent manner. SalB administration ameliorated the generation of oxidative products and preserved antioxidant defense activities in the injured spinal cord at both 4 and 24 h after I/R injury. Moreover, SalB prolonged the I/R injury–induced activation of extracellular signal–regulated kinase (ERK), and blocking ERK activation with PD98059 partially prevented the neuroprotective effects of SalB.

Conclusions

These findings demonstrate the neuroprotective effects of SalB in a spinal cord I/R injury model and suggest that SalB-induced neuroprotection was mediated by ERK activation.     

The antioxidant effect of β-Glucan on oxidative stress status in experimental spinal cord injury in rats

This study was performed to investigate the antioxidant effect of beta-Glucan in experimental spinal cord injury (SCI). Injury was produced using weight-drop technique in rats. beta-Glucan was given by intraperitoneal injection following trauma. The rats were sacrificed at the sixth day of injury. Oxidative stress status was assessed by measuring the spinal cord tissue content of Malonyldialdehyde (MDA), Superoxide Dismutase (SOD) and Gluthatione Peroxidase (GSH-Px) activities. No effect of beta-Glucan on SOD and MDA activities was found but, GSH-Px levels were found to decrease to the baseline (preinjury) levels when it was compared to untreated group (U=0.000; p=0.002). According to our results, beta-Glucan works like a scavenger and has an antioxidant effect on lipid peroxidation in spinal cord injury.     

Incidence of traumatic spinal cord injury in Aragón, Spain (1972-2008)

Long-term incidence studies are required to identify high-risk groups, establish trends, and forecast needs, and thus contribute to health care planning in spinal cord injury (SCI). This study aimed to determine the incidence of traumatic SCI over a 36-year period in Aragón, Spain, and compare rates with other published European estimates. Hospital records from the Servet Hospital, the only specialized SCI unit in the region, of a retrospective cohort with traumatic SCI between January 1972 and December 2008 were reviewed. Specification of SCI patient demographics, injury causes, and related factors was achieved by utilizing medical records available for inpatients, hospital archives, and central databases. A total of 540 cases were reported over the 36-year study period (79% were male). The age- and sex-adjusted incidence rate was 15.5 per million population (18.8 for males and 4.9 for females). Two incidence peaks were suggested, in the 20- to 29-year and 60- to 69-year age groups. Traffic accidents and falls were the main causes of injury. The highest peak occurs in young adults, mainly caused by traffic accidents. The majority of the lesions were at cervical or thoracic level, and ASIA grade A was most frequently observed. The proportion of SCI cases in persons older than 60 years, mostly due to falls, is increasing. The age-adjusted incidence rates found for the region of Aragón in Spain fall within the range of other published European estimates. Comparative epidemiological features for 2001-2008 suggest that there is room for prevention.