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.     

Effect of decompressive craniectomy on aquaporin-4 expression after lateral fluid percussion injury in rats

Decompressive craniectomy is one therapeutic option for severe traumatic brain injury (TBI), and it has long been used for the treatment of patients with malignant post-traumatic brain edema. A lack of definitive evidence, however, prevents physicians from drawing any conclusions about the effects of decompressive craniectomy for the treatment of TBI. Therefore, the aim of the present study was to investigate the influence of decompressive craniectomy on post-traumatic brain edema formation. The aquaporin-4 (AQP4) water channel is predominantly expressed in astrocytes, and it plays an important role in the regulation of brain water homeostasis. In the present study, we investigated the time course of AQP4 expression and the water content of traumatized cortex following decompressive craniectomy after TBI. Adult male Sprague-Dawley rats (300-400?g) were subjected to lateral fluid percussion injury using the Dragonfly device. The effect of decompressive craniectomy was studied in traumatized rats without craniectomy (closed skull, DC-), and in rats craniectomized immediately after trauma (DC+). AQP4 expression was investigated with a Western blot analysis and immunohistochemistry. Brain edema was measured using the wet weight/dry weight method. At 48?h after TBI, AQP4 expression of the DC- group was significantly increased compared with the DC+ group (p?相似文献   

The role of neuropeptide Y and aquaporin 4 in the pathogenesis of intestinal dysfunction caused by traumatic brain injury

Background

Although the exact incidence is unknown, traumatic brain injury (TBI) can lead to intestinal dysfunction. It has important influence on the early nutrition and prognosis of TBI patients. Experiments were designed to study the roles of neuropeptide Y (NPY) and aquaporin 4 (AQP4) in the pathogenesis of intestinal dysfunction caused by TBI and to find some new solutions for the treatment of intestinal dysfunction after TBI.

Methods

Forty adult male Wistar rats were randomly divided into control, mild trauma, moderate trauma, and severe trauma groups. TBI was induced by Feeney's impact method. Control animals were sham operated but not subjected to the impact test. All rats were killed 24 h after surgery. Blood samples were obtained from the abdominal aorta for enzyme-linked immunosorbent assay measurement of NPY concentrations. Jejunum segments 15 cm distal to the Treitz ligament were taken for analysis of NPY and AQP4 expression by polymerase chain reaction, Western blot, and immunohistochemistry. Pathologic changes in intestinal cell structure and ultrastructure were studied by light microscopy and transmission electron microscopy.

Results

The specimens from different groups showed different degrees of structural changes, ranging from swelling and degeneration of villous epithelial cells to extensive denudation and collapse of the villi. The more severe the trauma, the more serious the degree of intestinal mucosal injury. Intestinal smooth muscle also showed varying degrees of edema and structural disorder. Electron microscopy showed that intestinal mitochondria had varying degrees of swelling and the structure of mitochondrial crista was disordered and even fractured. Plasma concentrations of NPY and jejunal gene and protein expressions of NPY and AQP4 increased significantly following TBI (P < 0.05), with greater increases at higher levels of injury. Moreover, there were positive correlations between NPY and AQP4 (P < 0.05).

Conclusions

Increasing grades of TBI caused increasing degrees of intestinal ischemia and edema, and thus caused increasingly severe intestinal dysfunction. AQP4 and NPY may be involved in the pathogenesis of intestinal dysfunction after TBI. Increased NPY levels may be responsible for intestinal ischemia and hypoxia, and AQP4 may play an important role in intestinal edema. Increased NPY levels may be one of the main causes for the increase in AQP4 after TBI.     

Involvement of mitogen-activated protein kinase pathways in expression of the water channel protein aquaporin-4 after ischemia in rat cortical astrocytes

Abstract Brain edema after ischemic brain injury is a key determinant of morbidity and mortality. Aquaporin-4 (AQP4) plays an important role in water transport in the central nervous system and is highly expressed in brain astrocytes. However, the AQP4 regulatory mechanisms are poorly understood. In this study, we investigated whether mitogen-activated protein kinases (MAPKs), which are involved in changes in osmolality, might mediate AQP4 expression in models of rat cortical astrocytes after ischemia. Increased levels of AQP4 in primary cultured astrocytes subjected to oxygen-glucose deprivation (OGD) and 2?h of reoxygenation were observed, after which they immediately decreased at 0?h of reoxygenation. Astrocytes exposed to OGD injury had significantly increased phosphorylation of three kinds of MAPKs. Treatment with SB203580, a selective p38 MAPK inhibitor, or SP600125, a selective c-Jun N-terminal kinase inhibitor, significantly attenuated the return of AQP4 to its normal level, and SB203580, but not SP600125, significantly decreased cell death. In an in vivo study, AQP4 expression was upregulated 1-3 days after reperfusion, which was consistent with the time course of p38 phosphorylation and activation, and decreased by the p38 inhibition after transient middle cerebral artery occlusion (MCAO). These results suggest that p38 MAPK may regulate AQP4 expression in cortical astrocytes after ischemic injury.     

NF-κB在颅脑损伤后继发氧化应激及细胞凋亡之间的关系研究

目的：探讨NF-κB在颅脑损伤后继发氧化应激及细胞凋亡之间的关系及可能机制。方法成年健康雄性SD大鼠48只,随机分为对照组（n=6）和颅脑损伤组（n=42）。颅脑损伤组通过改良Feeney法建立颅脑损伤模型,根据伤后处死时间分为1、3、6、12及24小时、3和7天共7个亚组,每亚组各6只。每亚组随机取3只大鼠处死,取挫伤灶周围组织行脑组织超氧化物歧化酶（SOD）、丙二醛（MDA）、谷胱甘肽（GSH）测定;剩余的3只大鼠采用免疫组织化学方法检测挫伤灶周围脑组织中NF-κB的表达情况,同时采用TUNEL法观察脑挫伤灶周围细胞凋亡情况。结果颅脑损伤后1小时可见NF-κB蛋白明显表达,3~12小时表达逐渐加强,并于24小时达到高峰,3~7天表达稍减弱,但仍为高表达状态;NF-κB蛋白表达与MDA、SOD及GSH相关（r=0.731, r=-0.702, r=-0.674,P值均〈0.05）,与细胞凋亡水平相关（r=0.720, P〈0.05）。结论颅脑损伤后NF-κB蛋白表达的变化规律参与了继发性脑损伤中氧化应激反应及细胞凋亡等病理过程,抑制氧化应激水平,控制细胞凋亡,减少或减轻继发性脑损伤。     

Aquaporin-4 and brain edema

Aquaporin-4 (AQP4) is a water-channel protein expressed strongly in the brain, predominantly in astrocyte foot processes at the borders between the brain parenchyma and major fluid compartments, including cerebrospinal fluid (CSF) and blood. This distribution suggests that AQP4 controls water fluxes into and out of the brain parenchyma. Experiments using AQP4-null mice provide strong evidence for AQP4 involvement in cerebral water balance. AQP4-null mice are protected from cellular (cytotoxic) brain edema produced by water intoxication, brain ischemia, or meningitis. However, AQP4 deletion aggravates vasogenic (fluid leak) brain edema produced by tumor, cortical freeze, intraparenchymal fluid infusion, or brain abscess. In cytotoxic edema, AQP4 deletion slows the rate of water entry into brain, whereas in vasogenic edema, AQP4 deletion reduces the rate of water outflow from brain parenchyma. AQP4 deletion also worsens obstructive hydrocephalus. Recently, AQP4 was also found to play a major role in processes unrelated to brain edema, including astrocyte migration and neuronal excitability. These findings suggest that modulation of AQP4 expression or function may be beneficial in several cerebral disorders, including hyponatremic brain edema, hydrocephalus, stroke, tumor, infection, epilepsy, and traumatic brain injury.     

Astrocyte oxidative metabolism and metabolite trafficking after fluid percussion brain injury in adult rats

Despite various lines of evidence pointing to the compartmentation of metabolism within the brain, few studies have reported the effect of a traumatic brain injury (TBI) on neuronal and astrocyte compartments and/or metabolic trafficking between these cells. In this study we used ex vivo 13C NMR spectroscopy following an infusion of [1-13C] glucose and [1,2-13C?] acetate to study oxidative metabolism in neurons and astrocytes of sham-operated and fluid percussion brain injured (FPI) rats at 1, 5, and 14 days post-surgery. FPI resulted in a decrease in the 13C glucose enrichment of glutamate in neurons in the injured hemisphere at day 1. In contrast, enrichment of glutamine in astrocytes from acetate was not significantly decreased at day 1. At day 5 the 13C enrichment of glutamate and glutamine from glucose in the injured hemisphere of FPI rats did not differ from sham levels, but glutamine derived from acetate metabolism in astrocytes was significantly increased. The 13C glucose enrichment of the C3 position of glutamate (C3) in neurons was significantly decreased ipsilateral to FPI at day 14, whereas the enrichment of glutamine in astrocytes had returned to sham levels at this time point. These findings indicate that the oxidative metabolism of glucose is reduced to a greater extent in neurons compared to astrocytes following a FPI. The increased utilization of acetate to synthesize glutamine, and the acetate enrichment of glutamate via the glutamate-glutamine cycle, suggests an integral protective role for astrocytes in maintaining metabolic function following TBI-induced impairments in glucose metabolism.     

大鼠脑损伤后NF—κB的变化及地塞米松干预研究

目的观察大鼠脑损伤后NF—κB活性的变化及地塞米松对其影响。方法将28只SD大鼠完全随机分为：假手术组（4只）;损伤组（12只）;地塞米松干预组（12只）;建立大鼠液压颅脑损伤模型,假手术组不予处理,损伤组给予液压打击处理,干预组于打击后立即腹腔注射地塞米松,采用SP法测定NF—κB的活化情况。结果损伤组NF—κB活性较假手术组表达明显,在损伤后6、24、48小时其表达渐增强（P〈0．05）,地塞米松干预后其活性表达减弱（P〈0．05）。结论NF—κB的活性子损伤后表达增强,并于损伤6、24、48小时活性表达增强趋势,地塞米松可抑制其表达。     

Aquaporin-4 and traumatic brain edema

Brain edema leading to an expansion of brain volume has a crucial impact on morbidity and mortality following traumatic brain injury as it increases intracranial pressure, impairs cerebral perfusion and oxygenation, and contributes to additional ischemic injuries. Classically, two major types of traumatic brain edema exist： ＂vasogenic＂ and ＂cytotoxic/cellular＂. However, the cellular and molecular mechanisms contributing to the development/resolution of traumatic brain edema are poorly understood and no effective drugs can be used now. Aquaporin-4 （AQP4） is a water-channel protein expressed strongly in the brain, predominantly in astrocyte foot processes at the borders between the brain parenchyma and major fluid compartments,including cerebrospinal fluid and blood. This distribution suggests that AQP4 controls water fluxes into and out of the brain parenchyma. In cytotoxic edema, AQP4 deletion slows the rate of water entry into brain, whereas in vasogenic edema, AQP4 deletion reduces the rate of water outflow from brain parenchyma. AQP4 has been proposed as a novel drug target in brain edema. These findings suggest that modulation of AQP4 expression or function may be beneficial in traumatic brain edema.     

Expression of intestinal myeloid differentiation primary response protein 88 (Myd88) following experimental traumatic brain injury in a mouse model

BackgroundTraumatic brain injury (TBI) can cause gastrointestinal dysfunction and increase intestinal permeability. Nuclear factor kappa B (NF-κB) has been shown to be associated with these intestinal events, but it is not well known how NF-κB is activated in the intestine after TBI. Based on previous studies, we hypothesize that myeloid differentiation primary response protein 88 (Myd88) may have an important role in NF-κB activation in the intestine, which mediates the inflammation and ultimately results in acute intestinal mucosal injury.MethodsWe randomly divided adult male C57BL/6 mice into control groups and TBI groups at different time points. We induced a closed head injury model by weight drop (a 333-g metal rod dropping from a 2.5-cm height). We detected Myd88 protein level and NF-κB binding activity in ileum tissue by Western blot and electrophoretic mobility shift assay, respectively. Meanwhile, we detected the mRNA levels of Myd88, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and intercellular adhesion molecule-1 by real-time polymerase chain reaction.ResultsThe Myd88 protein and mRNA levels, as well as NF-κB binding activity in the ileum tissue, significantly increased at 6 h after TBI, peaked at 3 d, and remained elevated by 5 d post-injury. The levels of TNF-α, IL-1β, and intercellular adhesion molecule-1 also remarkably increased after TBI. There was a positive relationship between the expression of Myd88 and that of NF-κB, TNF-α, and IL-1β.ConclusionsTraumatic brain injury induced a rapid and persistent up-regulation of Myd88, NF-κB, and proinflammatory cytokines in the intestine. This up-regulation which might have an important role in the pathogenesis of acute intestinal mucosal injury.     

Suppressive effects of levobupivacaine on endotoxin-induced microglial activation

Background

We sought to elucidate the effects of levobupivacaine on modulating endotoxin-induced upregulation of inflammatory mediators and activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs) signaling pathways in activated microglia.

Materials and methods

Confluent murine microglia (BV-2) were treated with endotoxin (lipopolysaccharide, 50 ng/mL) or endotoxin plus levobupivacaine (5, 25, or 50 μM) and denoted as the LPS, LPS + L(5), LPS + L(25), and LPS + L(50) groups, respectively. Levobupivacaine was administered immediately after endotoxin. Control groups were run simultaneously.

Results

The concentrations of inflammatory mediators, including macrophage inflammatory protein-2 (P = 0.023 and 0.016), tumor necrosis factor-α (P = 0.025 and 0.020), interleukin (IL)-1β (P = 0.018 and 0.014), IL-6 (P = 0.029 and 0.023), nitric oxide (P = 0.025 and 0.026), and prostaglandin E₂ (P = 0.028 and 0.016) of the LPS + L(25) and LPS + L(50) groups were significantly lower than those of the LPS group. The concentrations of macrophage inflammatory protein-2 (P = 0.035), IL-1β (P = 0.024), nitric oxide (P = 0.031), and prostaglandin E₂ (P = 0.036) but not tumor necrosis factor-α and interleukin-6 of the LPS + L(5) group were also significantly lower than those of the LPS group. These data revealed that effects of endotoxin on upregulating inflammatory mediators were inhibited by levobupivacaine. Moreover, effects of endotoxin on activating NF-κB, including inhibitor-κB degradation, NF-κB nuclear translocation, and NF-κB–DNA binding, were also inhibited by levobupivacaine. Similarly, effects of endotoxin on activating MAPKs, including extracellular signal–regulated kinase, c-jun N-terminal kinase, and p38 MAPK, were also significantly inhibited by levobupivacaine.

Conclusions

Levobupivacaine significantly inhibited endotoxin-induced upregulation of inflammatory mediators and activation of NF-κB and MAPKs signaling pathways in activated microglia.     

Traumatic injury activates protein kinase B/Akt in cultured astrocytes: role of extracellular ATP and P2 purinergic receptors

Protein kinase B/Akt is a key signaling molecule that regulates cell survival, growth, and metabolism, and inhibits apoptosis. Traumatic brain injury (TBI) activates Akt, and Akt has been implicated in neuronal survival after TBI, but little is known about injury-induced Akt activation in astrocytes, cells that exhibit hypertrophic and hyperplastic responses to CNS injury. Here we have investigated the effect of mechanical strain on Akt activation in primary cultures of rat cortical astrocytes growing on deformable Silastic membranes. When astrocytes were subjected to mechanical strain (50 msec; 5-7.5 mm displacement), we observed an increase in phosphorylation of serine 473, a key indicator of Akt activation. Akt phosphorylation was increased at 3 min postinjury, was maximal from 5 to 10 min, and declined gradually thereafter. Akt activation was also dependent on the severity of the injury. Stretch-induced Akt phosphorylation was attenuated by blocking calcium influx and phosphoinositide 3-kinase (PI3K), an upstream activator of Akt. In addition, we found that ATP is rapidly released after mechanical strain and that the P2 purinergic receptor antagonist iso-pyridoxal-5'-phosphate-6-azophenyl-2',5'disulfonate (PPADS) attenuated trauma-induced Akt activation. We conclude that mechanical strain causes activation of Akt in astrocytes via stimulation of P2 receptors. This suggests that P2 receptor/Akt signaling promotes astrocyte survival and growth, and this process may play a role in the generation of reactive gliosis after TBI.     

脑死亡时猪肝脏功能及组织学改变的研究

目的 观察脑死亡对猪肝脏功能、形态的影响并探讨核因子κB(nuclear factor κB,NF-κB)在脑死亡发生机制中的作用.方法 健康长白猪12头,随机分为2组:对照组6头,仅行麻醉维持24 h;脑死亡组6头,建立猪脑死亡模型并维持脑死亡状态24 h.脑死亡后(对照组持续麻醉后)6、12、24 h取血标本及开腹取同一部位肝组织,检测血清中丙氨酸氨基转移酶(alanine aminotransferase,ALT)、天冬氨酸氨基转移酶(espartate aminotransferase,AST)水平;ELISA法检测血清白细胞介素1β(intedeukin-1β,IL-1β)水平;实时荧光定量PCR(real-time fluorescence quantitative polymerase chain reaction,real-time PCR)法检测肝组织NF-κB mRNA变化;免疫组织化学法观察肝组织NF-κB p65蛋白表达情况.结果 脑死亡组长白猪各时间点血清ALT、AST、IL-1β水平、肝组织NF-κB mRNA转录水平及肝组织NF-κB p65蛋白表达水平均较对照组高,两者相比差异有统计学意义(P<0.05).脑死亡组脑死亡后12 h肝细胞轻度浊肿;24 h细胞水肿,肝细胞疏松化.结论 脑死亡导致猪肝脏出现功能与形态学的损伤性变化.其机制可能是脑死亡引起肝细胞NF-κB mRNA 转录和蛋白翻译水平升高,进而导致机体炎症介质合成与释放.     

Effect of penetrating brain injury on aquaporin-4 expression using a rat model

Cerebral edema (CE) is a frequent and potentially lethal consequence of various neurotraumas, including penetrating brain injury (PBI). Aquaporin-4 (AQP4) water channel is predominantly expressed by astrocytes and plays an important role in regulating water balance in the normal and injured brain. Using a rat model of PBI, we show that AQP4 immunoreactivity was substantially increased in the peri-injury area at both 24 and 72 h after PBI. The increase in AQP4 expression was paralleled by increased GFAP expression. The two proteins were co-expressed by peri-vascular astrocytes, whereas reactive astroglia identified by their stellar morphology did not express AQP4 at either time points after injury. Western analysis confirmed the increase in AQP4 immunoreactivity observed in the injured tissue. The apparent increase in AQP4 immunoreactivity was likely due to de novo AQP4 protein synthesis, as most of the increased AQP4 immunoreactivity was found in the soluble (cytosolic) fraction. Our results demonstrate dynamic spatial and temporal changes in AQP4 expression that contribute to the molecular pathophysiology of PBI.     

ROBOTIC NEUROSURGERY—QUEEN ELIZABETH HOSPITAL EXPERIENCE

To assess changes of aquaporin‐4 (AQP4) and dissect out responses of endothelia and foot process of astrocytes in severe Traumatic Brain Injury (TBI) rat model. 32 rats were randomly divided into different groups. Immunohistochemistry was conducted using: 1) anti‐endogenous IgG, 2) anti‐Endothelial Barrier Antigen (EBA), 3) anti‐Aquaporin 4 (AQP4). The negatively stained areas of EBA and AQP4 on two adjacent serial sections from the same contusion were also quantified by image analysis (CAS 200, Beckton‐Dickinson). Results showed: 1) Damages of BBB indirectly detected by endogeneous IgG were mostly concentrated in contusions (started from 1 hour till 11 day) but not significantly changed in contalateral cortex and brain stem being diffusely injured. 2) Loss of AQP4 expression was also prominent in contusion at 1 day (5/6) and re‐expression started from 3 day (2/5) and afterwards. However, loss of EBA in contusion peaked at 4 hours and 1 day (5/6), re‐expression started from 1 day (4/6) and later. 3) AQP4 (–) area within contusion was significantly larger than EBA (–) area, compared between two adjacent serial sections from the same contusion [1.68 ± 0.46 mm² (AQP4‐negative) versus 0.47 ± 0.12 mm² (EBA‐negative) (mean ± S.E.M., P = 0.01, paired t‐test)]. It can be concluded that AQP4 (–) in the focal contusion is associated with damaged BBB. The combined immunostaining of EBA and IgG can define the dynamic process of BBB damage. Heterogeneous responses of perivascular foot process of astrocyte and endothelia are evoked when exposed to the same direct mechanical injury loading in contusion. The peri‐vascular foot process of astrocyte is more vulnerable.     

Phenylephrine infusion prevents impairment of ATP- and calcium-sensitive potassium channel-mediated cerebrovasodilation after brain injury in female, but aggravates impairment in male, piglets through modulation of ERK MAPK upregulation

Traumatic brain injury (TBI) contributes to morbidity in children and boys, and hypotension worsens outcome. Extracellular signal-related kinase (ERK) mitogen-activated protein kinase (MAPK) is upregulated more in males and reduces cerebral blood flow (CBF) after fluid percussion injury (FPI). Increased cerebral perfusion pressure (CPP) via phenylephrine (Phe) sex-dependently improves impairment of the cerebral autoregulation seen after FPI through modulation of ERK MAPK upregulation, which is aggravated in males, but is blocked in females. Activation of ATP- and calcium-sensitive (Katp and Kca) channels produces cerebrovasodilation and contributes to autoregulation, both of which are impaired after FPI. Using piglets equipped with a closed cranial window, we hypothesized that potassium channel functional impairment after FPI is prevented by Phe in a sex-dependent manner through modulation of ERK MAPK upregulation. The Katp and Kca agonists cromakalim and NS 1619 produced vasodilation that was impaired after FPI more in males than in females. Phe prevented reductions in cerebrovasodilation after cromakalim and NS 1619 in females, but reduced dilation after these potassium channel agonists were given to males after FPI. Co-administration of U 0126, an ERK antagonist, and Phe fully restored dilation to cromakalim, calcitonin gene-related peptide (CGRP), and NS 1619, in males after FPI. These data indicate that Phe sex-dependently prevents impairment of Katp and Kca channel-mediated cerebrovasodilation after FPI in females, but aggravates impairment in males, through modulation of ERK MAPK upregulation. Since autoregulation of CBF is dependent on intact functioning of potassium channels, these data suggest a role for sex-dependent mechanisms in the treatment of cerebral autoregulation impairment after pediatric TBI.     

Kinetics of the cellular immune response following closed head injury

Summary Background. The contribution of brain edema to brain swelling in cases of traumatic brain injury (TBI) remains a critical problem. We believe that inflammatory reactions may play a fundamental role in brain swelling following a head injury. Although possible roles of microglia activation and the release of mediators have been suggested, direct evidence of cellular immune reactivity in diffuse brain injury following closed head trauma is lacking. Accordingly, the objective of this study was to assess the temporal pattern of microglia activation and lymphocyte migration in an experimental model of TBI. Method. An impact acceleration TBI model was utilized to induce diffuse brain damage in adult Wistar rats. The animals were separated into three groups: unoperated controls, sham-operated controls and trauma group. At various times after TBI induction (5 min–24 h), rats were perfused transcardially. Sagittal brain sections were analyzed with immunohistochemical markers of CD3 to reveal the presence of T-lymphocytes, and by immunochemistry for the detection of CD11b to reveal microglia activation within the brain parenchyma. Findings. In the control groups, scattered T-cells were found in the brain parenchyma. In the trauma group, TBI induced microglia activation and a transient biphasic T-cell infiltration of the brain parenchyma in all regions was found, beginning as early as 30 min post injury and reaching its maximum values at 45 min and 3 h after trauma induction. Conclusion. These results lead us to suggest that the acute response to severe head trauma with early edema formation is likely to be associated with inflammatory events which might be triggered by activated microglia and infiltrating lymphocytes. It is difficult to overestimate the clinical significance of these observations, as the early and targeted treatment of patients with severe head injuries with immunosuppressive medication may result in a far more favorable outcome.     

一氧化氮增加人软骨肉瘤细胞表达基质金属蛋白酶-13的机制研究

目的研究一氧化氮(NO)是否通过MAPK和NF-κB通路增加基质金属蛋白酶-13(MMP-13)的表达,探讨骨关节炎(OA)发病机制中NO的作用。方法购买并传代人软骨肉瘤细胞(SW1353),用不同浓度的NO供体MAHMA-NONOate刺激后检测MMP-13以及MAPK和NF-κB通路中的蛋白激酶的表达水平。用不同浓度的MAPK和NF-κB通路中的蛋白激酶的抑制剂预先处理细胞后,再用MAHMA-NONOate刺激细胞,再次检测MMP-13以及MAPK和NF-κB通路中的蛋白激酶的表达水平。结果 MAHMA-NONOate增加了细胞MMP-13的表达水平,同时也增加了MAPK和NF-κB通路中的蛋白激酶的活性水平,MAPK家族中的JNK的抑制剂SP600125可以抑制MMP-13的表达水平,NF-κB的抑制剂SN5O也可以抑制MMP-13的表达水平。结论 NO可以通过MAPK家族中的JNK和NF-κB通路增加MMP-13的表达。