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ABSTRACT: OBJECTIVE: NF-E2-related factor 2 (Nrf2) is a transcription factor that is related to tumor cell multidrug resistance and proliferation. Here we studied the involvement of Nrf2 in the migration and invasion of human U251 glioma cells. METHODS: Two kinds of plasmid, that is, pEGFP-Nrf2 and Si-Nrf2, were constructed and transfected to upregulate or downregulate the expression of Nrf2 in U251 glioma cell line. Blank vectors or random siRNA plasmid were used as negative control. Cells treated with lipofectamine only were set up as blank control. Protein and mRNA level of Nrf2 and matrix metalloproteinase 9 (MMP9) were investigated by reverse transcriptase-polymerase chain reaction and western blot after transfection. Wound healing assay and transwell assay were used to study migration and invasion of U251 after transfection. Gelatin zymography was performed to reveal the change of MMP9 activity after transfection. RESULTS: The mRNA and protein level of Nrf2 was upregulated in U251-pEGFP-Nrf2 while downregulated in U251-Si-Nrf2 48 hours after transfection. In the wound healing assay, there were more cells in group pEGFP-Nrf2 crossing the scratch line than in group Si-Nrf2. Furthermore, in transwell migration and invasion assay, there were more cells in group pEGFP-Nrf2 penetrating the membranes than in group Si-Nrf2. Then we investigated the change of MMP9 activity, mRNA, and protein levels after transfection. The results suggested that upregulation of Nrf2 led to an increase in MMP9 expression and activity whereas downregulation of Nrf2 led to a decrease in MMP9 expression and activity. CONCLUSION: Nrf2 is involved in migration and invasion of U251 cells, which may be related to MMP9.
World Neurosurgery 11/2011; · 0.68 Impact Factor
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ABSTRACT: Nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element pathway has been proved to be the key regulator in reducing inflammatory damage, which is involved in subarachnoid hemorrhage (SAH). Here, in a traditional in vitro SAH model, we investigated the effect of Nrf2 depletion on pro-inflammatory cytokines production. Primary cultured astrocytes from Nrf2 wild type (WT) or knockout (KO) mouse were exposed or not exposed to oxyhemoglobin (OxyHb). Then the DNA-binding activity of transcription factor nuclear factor-κB (NF-κB) was detected by EMSA. The expression of TNF-α, IL-1β, IL-6 and MMP9 were evaluated. The activity of MMP9 was measured by Gelatin zymography. After exposure to OxyHb, NF-κB was activated and the expression of downstream pro-inflammatory cytokines was up-regulated in astrocytes. And such up-regulation was much higher in KO astrocytes than in WT astrocytes, which means more aggravated inflammation in Nrf2 deficient astrocytes. These results suggest that astrocytes participate in inflammatory process after SAH and the absence of Nrf2 may induce more aggressive inflammation through activation of NF-κB pathway.
Neurochemical Research 08/2011; 36(12):2434-41. · 2.24 Impact Factor
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ABSTRACT: Aquaporin-4 (AQP4) is a water channel protein and it is an important determinant of outcome after brain injury. Sulphoraphane (SFN) increases AQP4 levels with reduction of brain oedema at 3 days post-traumatic brain injury. However, little is known about the effect of SFN on AQP4 expression and oedema after spinal cord injury (SCI).
The present study used a murine SCI model induced by compression injury. AQP4 protein level and mRNA level were detected by Western blot and by RT-PCR at 48 hours after SCI, respectively. In addition, immunohistochemical study was used to show AQP4 expression in the spinal cord segments and water content of the spinal cord segments were measured by wet?:?dry weight ratio.
This study shows that AQP4 level was decreased in the injured spinal cord segments at 48 hours following SCI. Post-injury administration of SFN increased AQP4 levels, which was accompanied by a significant reduction in spinal cord segment oedema at 48 hours post-injury.
These findings suggest that the reduction of spinal cord oedema in response to SFN administration could be due, in part, to water clearance by AQP4 from the injured spinal cord segments.
Brain Injury 01/2011; 25(3):300-6. · 1.36 Impact Factor
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ABSTRACT: Generally speaking, the term "ophthalmic aneurysms" refers to carotid-ophthalmic aneurysms, which arise from the internal carotid artery (ICA) wall at or around the origin of the ophthalmic artery (OA). In contrast, aneurysms arising from the OA stem or its branches, separate from the ICA are called peripheral OA aneurysms (POAAs). POAAs are a rare entity, which clinical features and natural course are not fully understood. A comprehensive literature review of reported aneurysms involving each segment of the OA was undertaken. The demographics, aetiology, clinical manifestations and treatment of reported POAAs are discussed. Of 35 retrieved cases, ten involved the intracranial segment, two were fusiform aneurysms in the optic canal, 17 arose from the intraorbital segment, and 6 involved either the lacrimal or the anterior ethmoidal branches. In 34 cases, clinical details were available; 18 patients experienced moderate to severe visual impairment including blindness, while seven patients had improvement in visual acuity as a result of surgical treatment. The present clinical review reveals that aneurysms of the OA stem and lacrimal branch are potentially threatening to visual acuity, while intracranial segment and anterior ethmoidal aneurysms can rupture and cause subarachnoid or intraparenchymal haemorrhage. Surgical intervention is mandatory in symptomatic cases to prevent visual deterioration or treat aneurismal rupture; alternatively, for small incidental POAAs "watchful waiting" may be indicated.
Neurosurgical Review 01/2011; 34(1):29-38. · 2.04 Impact Factor
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ABSTRACT: To investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) as a key transcription factor of cytoprotection against inflammation in the spinal cord upregulation of matrix metalloproteinase-9 (MMP-9), tumor necrosis factor-α(TNF-α) after spinal cord injury (SCI).
Wild-type Nrf2(+/+) and Nrf2(-/-)-deficient mice were subjected to a murine SCI model induced by the application of vascular clips (force of 10 g) to the dura after a three-level T8-T10 laminectomy. The wet/dry weight ratio was used to reflect the percentage of water content of impaired spinal cord tissue at 48 h after SCI. The mRNA levels of MMP-9 were determined using reverse-transcriptase polymerase chain reaction (RT-PCR), and the protein levels of TNF-α and MMP-9 were detected by enzyme-linked immunosorbent assay at 24 h after SCI. Furthermore, gelatin zymography analysis was used to show MMP-9 activity of spinal cord tissue at 24 h after SCI. Software SPSS 16.0 was used for the statistical analysis.
After SCI, spinal cord water content, the expression of TNF-α and MMP-9 all increased in both injured Nrf2(+/+) and Nrf2(-/-) mice compared with their respective sham-operated mice. However, Nrf2(-/-) mice were shown to have more severe spinal cord edema, more TNF-α expression, more production and activity of MMP-9 compared with their wild-type Nrf2(+/+) counterparts after SCI (P < 0.05).
The results suggest that Nrf2 plays an important protective role in limiting the spinal cord upregulation of TNF-α and MMP-9 after SCI. It may be a new therapeutic target of SCI.
Zhonghua wai ke za zhi [Chinese journal of surgery] 10/2010; 48(20):1569-72.
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ABSTRACT: Matrix metalloproteinase-9 (MMP-9) plays an important role in the acute periods of spinal cord injury (SCI), and its expression is related to the inflammation which could cause the disruption of the blood-spinal barrier (BBB). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a crucial role in cytoprotection against inflammation. The present study investigated the role of Nrf2 in upregulating of nuclear factor kappa B (NF-κB) activity, tumor necrosis factor-α (TNF-α), and MMP-9 after SCI. Wild-type Nrf2 (+/+) and Nrf2-deficient (Nrf (-/-)) mice were subjected to an SCI model induced by the application of vascular clips (force of 10 g) to the dura after a three-level T8-T10 laminectomy. We detected the wet/dry weight ratio of impaired spinal cord tissue, the activation of NF-κB, the mRNA and protein levels of TNF-α and MMP-9, and the enzyme activity of MMP-9. Nrf2 (-/-) mice were demonstrated to have more spinal cord edema, NF-κB activation, TNF-α production, and MMP-9 expression after SCI compared with the wild-type controls. The results suggest that Nrf2 may play an important role in limiting the upregulation of NF-κB activity, TNF-α, and MMP-9 in spinal cord after SCI.
Mediators of Inflammation 01/2010; 2010:238321. · 3.26 Impact Factor
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ABSTRACT: Inflammation plays an important role in the pathogenesis of secondary damage after spinal cord injury (SCI). The present study explored the effect of sulforaphane (SFN), a potent anti-inflammatory extract of cruciferous vegetables, on the expression of two inflammatory mediators, metalloproteinase (MMP)-9 and TNF-α, in a murine model of SCI. Murine spinal cord injury was induced by the application of vascular clips (force of 10 g) to the dura after a three-level T8-T10 laminectomy. The wet/dry weight ratio was used to reflect the percentage of water content of impaired spinal cord tissue at 48 hr after SCI. The mRNA levels of MMP-9 were determined using the reverse-transcriptase polymerase chain reaction (RT-PCR), and protein levels of TNF-α and MMP-9 were detected by enzyme-linked immunosorbent assays (ELISA) at 24 hr after SCI. Gelatin zymography was used to determine MMP-9 activity of spinal cord tissue at 24 hr after SCI. Mice treated with SFN at 1 hr after SCI had lower expression and activity of MMP-9 compared to mice with SCI. The decrease of MMP-9 in mice treated with SFN was associated with decreased levels of spinal cord water content and TNF-α. In summary, suforaphane decreases MMP-9 and TNF-α expression and vascular permeability changes following spinal cord injury in mice.
Annals of clinical and laboratory science 01/2010; 40(4):354-60. · 0.96 Impact Factor
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ABSTRACT: Erythropoietin (Epo) has been gaining great interest for its potential neuroprotective effect in various neurological insults. However, the molecular mechanism underlying how Epo exerts the function is not clear. Recent studies have indicated that Zn(2+) may have a key role in selective cell death in excitotoxicity after injury. In the present study, we studied the effect of recombinant human Epo (rhEpo) in zinc-induced neurotoxicity both in vitro and in vivo. Exposure of cultured hippocampal neurons to 200 muM ZnC1(2) for 20 min resulted in remarkable neuronal injury, revealed by assessing neuronal morphology. By measuring mitochondrial function using MTT assay, we found that application of rhEpo (0.1 U/ml) 24 h before zinc exposure resulted in a significant increase of neuronal survival (0.6007+/-0.2280 Epo group vs 0.2333+/-0.1249 in control group; n=4, p<0.01). Furthermore, we demonstrated that administration of rhEpo (5,000 IU/kg, intraperitoneal) 30 min after traumatic brain injury (TBI) in rats dramatically protected neuronal death indicated by ZP4 staining, a new zinc-specific fluorescent sensor which has been widely used to indicate neuronal damage after excitotoxic injury (n=5/group, p<0.05). Neuronal damage was also assessed by Fluoro-Jade B (FJB) staining, a highly specific fluorescent marker for the degenerating neurons. Consistent with ZP4 staining, we found the beneficial effects of rhEpo on neuronal survival in hippocampus after TBI (n=5/group, p<0.05). Our results suggest that rhEpo can significantly reduce the pathological Zn(2+) accumulation in rat hippocampus after TBI as well as zinc-induced cell death in cultured cells, which may potentially contribute to its neuronal protection after excitotoxic brain damage.
Brain research 08/2009; 1289:96-105. · 2.46 Impact Factor
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ABSTRACT: The ketogenic diet (the KD) is an effective treatment for intractable epilepsy, especially in the paediatric population, and a growing number of studies have shown the neuroprotective role of the KD. However, few studies focused on the neuroprotective effects of the KD in traumatic brain injury (TBI). The present study aimed to investigate the effects of the KD on TBI.
Male Sprague-Dawley rats (n = 60) were randomly divided into four groups according to the diet fed (the KD vs normal diet) and whether brain was injured or not. TBI was produced using Feeney weight drop model. Brain oedema was estimated by wet/dry weight ratio; Bax and Bcl-2 mRNA levels were determined by RealTime-PCR; Bax and Bcl-2 protein levels were detected by Western blot. Furthermore, cellular apoptosis in the penumbra area was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) method.
The results indicated that both Bax mRNA and protein levels were significantly elevated 72 hours after TBI and decreased by KD administration. Neither TBI nor the KD affected Bcl-2 mRNA and protein levels. KD administration also reduced brain oedema and cellular apoptosis.
These results suggest that the KD might be a useful treatment for children suffering from the consequences of TBI.
Brain Injury 06/2009; 23(5):459-65. · 1.36 Impact Factor
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ABSTRACT: Previous studies have shown that nuclear factor erythroid 2-related factor 2 (Nrf2) plays a unique role in many physiological stress processes. The present study investigated the role of Nrf2 in the regulation of traumatic brain injury (TBI)-induced acute lung injury (ALI). Wild-type Nrf2 (+/+) and Nrf2 (-/-)-deficient mice were subjected to a moderately severe weight-drop impact head injury. Pulmonary capillary permeability (PCP), wet/dry weight ratio, apoptosis, inflammatory cytokines and antioxidant/detoxifying enzymes were measured at 24 h after TBI. Mice lacking Nrf2 were found to be more susceptible to TBI-induced ALI, as characterized by the higher increase in PCP, wet/dry weight ratio and alveolar cells apoptosis after TBI. This exacerbation of lung injury in Nrf2-deficient mice was associated with increased pulmonary mRNA and protein expression of inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6); and with decreased pulmonary mRNA expression and enzymatic activities of antioxidant and detoxifying enzymes including NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase alpha1 (GST-alpha1)--as compared with their wild-type Nrf2 (+/+) counterparts after TBI. The results of the present study suggest that Nrf2 reduces TBI-induced acute lung injury, possibly by decreasing pulmonary inflammation and inducing antioxidant and detoxifying enzymes.
Experimental Biology and Medicine 03/2009; 234(2):181-9. · 2.64 Impact Factor
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ABSTRACT: Acute lung injury (ALI) is a frequent but poorly understood complication of traumatic brain injury (TBI). The Nrf2-ARE pathway has been proved to be essential for protection against diffuse inflammation and oxidative damage, which are both involved in ALI following TBI. However, whether the Nrf2-ARE pathway is activated after TBI in the lung hasn't been studied.
In the present study, the nuclear Nrf2 protein level was detected by Western blot and the mRNA levels of heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO1), two Nrf2-regulated gene products, were determined by RT-PCR at 24 hours after TBI. In addition, the expression of Nrf2 and HO-1 was localized by immunohistochemical study.
After TBI, the nuclear Nrf2 protein level in the lung was significantly increased and the mRNA levels of both HO-1 and NQO1 were also up-regulated. Moreover, immunohistochemical study showed that both Nrf2 and HO-1 were mainly localized in tracheobronchial epithelium and alveolar macrophages.
These results suggest that the Nrf2-ARE pathway is activated in the lung after TBI.
Brain Injury 10/2008; 22(10):802-10. · 1.36 Impact Factor
