Spatial alterations in endothelin receptor expression are temporally associated with the altered microcirculation after brain trauma

OBJECTIVES: To study the cellular distribution of endothelin receptors A and B (ETrA and ETrB) in the post-traumatic sensorimotor cortex and hippocampus. MATERIALS AND METHODS: We inflicted closed head trauma to male Sprague-Dawley rats and visualized ETrA and ETrB immunoreactivity with 3,3'-diaminobenzidine. RESULTS: ETrA immunolabeling was the most prominent in pyramidal neurons 24 and 48 hours post-trauma, while it reached its peak in the microvasculature at hour 4. ETrB immunolabeling was observed in endothelial cells, perivascular neurons, smooth muscle cells (SM) and pericytes, the expression being the most pronounced 24 hours post-trauma. DISCUSSION: The results suggest that the vasoconstrictor effect of endothelin-1 (ET-1) is mediated primarily by ETrA. The dual effects of ETrB are reflected in its vasoconstrictor role at the vascular bed and conversely, in the attenuation of ET-1 availability and synthesis. We conclude that both receptors play a role in the disturbed microvascular autoregulation and in the sustained reduction of blood flow following trauma to the brain.     

轻型颅脑损伤致脑梗死临床分析

目的探讨轻型颅脑损伤后发生脑梗死的特点、治疗及预后。方法统计2000年至2007年内25例此类患者,对其发生原因、发病特点,治疗及预后进行研究,并结合文献进行临床分析。结果青少年、老年人,全身多发损伤病人及不适当的治疗后轻型颅脑损伤患者易出现脑梗死;治疗应采用综合疗法;预后大多良好。结论对轻型颅脑损伤后脑梗死讨论对预防其发生在临床上有重要意义。     

脑损伤大鼠血浆及海马内皮素—1、肿瘤坏死因子变化的实验研究

用RIA法测定脑损伤大鼠血浆及海马匀浆中ET-1、TNF-a含量变化,研究ET-1、TNF-a对海马神经原坏死的影响。结果:血浆及海马ET-1、TNF-a水平在脑损伤后各时间点均明显高于对照组,二者具有显著相关性;且ET-1、TNF-a含量变化与病程有关。结论:脑损伤后ET-1、TNF-a增高是引起海马缺血、神经原坏死的重要原因。     

Role of endothelin-1 in astrocyte responses after acute brain damage

We examined the possibility of the involvement of endothelin (ET)-1, a potent vasoactive peptide, in the process of astrocyte proliferation after brain injury. Acute brain damage in rats was induced by cold-injury. Astrocytes changed from a differentiated state to an immature, RC-1-positive state immediately after the injury. In the injured site, the level of ET-1-like immunoreactivity in the tissue was significantly increased on the first postoperative day and was sustained at a high level for 5 days. ET_B receptor mRNA was markedly but transiently down-regulated only on the first day after the injury. Brain extracts (BE) were prepared from the injured tissues, and their effects on the proliferative characteristics of astrocytes were examined in primary culture of astrocytes. The flat morphology, which was observed in association with cell proliferation, and DNA synthesis of astrocytes were enhanced by treatment with each of the BE from 1 (D1-BE), 3 and 5 days after the injury. A monoclonal antibody that recognizes the C-terminus of rat ET-1 and ET-3 inhibited the DNA synthesis of astrocytes induced by D1-BE. These results provide experimental evidence that ET-1 may participate in the initiation of gliosis in the acute phase of brain damage. J. Neurosci. Res. 47:590–602, 1997. © 1997 Wiley-Liss, Inc.     

血晶素诱导血红素氧合酶-1在脑外伤中的表达及意义

目的 探讨血红素氧合酶-1(HO-1)在颅脑外伤中的作用. 方法 48只SD大鼠按照随机数字表法分为血晶素处理组、生理盐水组和假手术组.用液压冲击伤复制颅脑外伤的大模型,伤后予以45mg/100mg体质量血晶素、生理盐水腹腔注射干预HO-1的表达.假手术组只切开头皮,颅骨钻孔.其他不作任何处理.斜坡试验观测大的行为学改变.尾静脉注射伊文思兰测定血脑屏障的通透性.SP免疫组织化学测定HO-1的表达. 结果 血晶素处理组HO-1的表达[(125.52±14.39)个]较生理盐水组[(100.63±12.32)个]和假手术组[(79.37±12.89)个]明显增加,差异有统计学意义(P<0.05).血晶素处理组大鼠斜坡试验时间[(7.38±1.69)s]较生理盐水组[(10.01±1.61)s]缩短,差异有统计学意义(P<0.05).血晶素处理组血脑屏障的通透性较生理盐水组明显降低.差异有统计学意义(P<0.05). 结论 HO-1在颅脑外伤中的表达对中枢神经系统具有保护作用.     

Accumulation of calcium in the brain following head trauma

Previous studies have reported accumulation of calcium (Ca) in brain tissue of injured or ischaemic experimental animals. In the present study, head trauma (HT) was induced in the left hemisphere of rats which were subsequently sacrificed 15 min, 1, 2, 4, 24 or 48 h later. Their brains were analysed for oedema formation by the determination of specific gravity (SG), using linear gradient columns, and water content, by dry to wet weight ratio. Total tissue Ca content was measured by atomic absorption spectroscopy. These values, in both the injured and contralateral hemispheres were compared with values obtained from sham-operated rats. Specific gravity of the contused hemisphere was lower than that of the contralateral hemisphere or sham and its water content was higher, at all time points studied. Calcium content was significantly higher in the contused grey matter at 1 h, and in the grey and white matter of both hemispheres at 24 and 48 h after HT. Statistical analysis revealed excellent correlation (cc = 0.65, p less than 0.001) between Ca levels and water content in the grey matter, whenever Ca concentrations were elevated (1, 24 and 48 h). These findings suggest that in the late phase of the post-HT period, Ca accumulation might play a role, along with other mediators, in the development of brain oedema after HT.     

内皮素－1和内皮素－3对实验动物脑血管的不同反应

利用电脑视屏下记录观察离体活组织脑切片技术，对内皮素－１（ＥＴ－１），内皮素－３（ＥＴ－３）在蒙古沙鼠离体活组织脑血管的反应进行记录分析。发现ＥＴ－１引起脑血管强烈收缩，收缩特点随药物浓度增加而加强。但ＥＴ－３没有引起脑血管强烈的收缩。这种不同的反应特点，支持了存在不同内皮素族受体的观点。ＥＴ－３在有损伤的血管内皮上起调节作用。     

Locked-in syndrome after head and neck trauma

Ten patients became locked-in after head and neck trauma. Five had a prompt onset due to either direct trauma or secondary infarction of the brainstem. A delay of 6 to 48 hours in four other patients was probably the interval between vertebral artery damage and vertebrobasilar arterial occlusion. The last patient sustained ischemia and compression of the cerebral peduncles from tentorial herniation.     

Abnormalities of taste and smell after head trauma

Abnormalities of taste and smell were studied in 29 patients after head trauma. These abnormalities included decreased taste acuity (hypogeusia), a distortion of taste acuity (dysgeusia), decreased smell acuity (hyposmia), and a distortion of smell acuity (dysosmia). This syndrome can occur even after minimal head trauma and can begin months after the moment of injury. The patients exhibited a significant decrease in total serum zinc concentration (patients, 77 ± 3 μg/100 ml, mean ± 1 SEM, vs controls, 99 ± 2 μg/100 ml, P>0·001) and a significant increase in total serum copper concentrations (113 ± 4 μg/100 ml vs 100 ± 2 μg/100 ml, P<0·001) compared with control subjects. Symptoms of hypogeusia, dysgeusia, and dysosmia are frequent sequelae of head injury and are important to the patients and to their care after trauma.     

Psychotropic management of behavioral disorders after head trauma

A rational basis for the psychopharmacologic management of behavioral disturbances after head trauma has been presented that is predicated on research in neurotransmitter changes that evolve subsequent to head trauma. The paucity of human studies in this area mandates the use of experimental models and evidence garnered from provocative challenges to suggest the underlying neurotransmitter profile in various behavioral abnormalities. Multiple neurotransmitter circuits exist that provide parallel, duplicate, and redundant systems for these behaviors. Certainly, alternative explanations could be offered for the examples cited above. Furthermore, measurement of neurotransmitter metabolite concentration in cerebrospinal fluid does not allow specific inferences to be made regarding topographic correlation and neurotransmitter function. Nor does it afford assessment of regional differences in psychotropic influence on neurotransmitter receptors. New imaging techniques (eg, positron emission tomography) will certainly aid in this determination. Current investigations, however, support the concept that neurotransmitter changes do occur after head injury, that these alterations exist during the time that "recovery" occurs, and that psychotropic agents influence this recovery process. Further research is needed to clarify neurotransmitter changes after head injury and to identify psychotropic intervention strategies that facilitate the recovery process.     

腺病毒介导BDNF基因转移对大鼠创伤性脑损伤后iNOS表达及细胞凋亡的影响

研究重组腺病毒介导的脑源性神经营养因子（brain derived neurotrophic factor,BDNF)基因转移对创伤性脑损伤（TBI）后诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS)表达及细胞凋亡的影响。将重组腺病毒载体4μl注入承受单侧大脑皮质重锤打击的大鼠海马,对照组注射病毒缓冲液。伤后3h及1,3,7,14d利用免疫组化单标／双标染色。原位杂交／组化染色及DNA末端原位标记等方法,检测伤侧大脑皮质和海马各多区iNOS、BDNF及凋亡相关信号表达的改变。与对照组相比,同伤组大脑皮质及海马各区iNOS阳性细胞于伤后3h开始显著增多,7d达高峰。多数iNOS阳性细胞同时呈现凋亡相关蛋白阳性反应或TUNEL阳性反应,但很少同时表达BDNF mRNA。注射病毒载体组后3,7d,海马CA1区和DH区表达iNOS、凋亡相关蛋白的细胞及凋亡细胞显著减少（P均＜0．01）,而表达BDNF mRNA的神经元显著增多。提示,TBI诱导海马细胞表达iNOS及诱导海马细胞凋亡;腺病毒介导的BDNF基因转移通过抑制iNOS表达、增加BDNF表达及减少细胞凋亡的机制保护海马神经元。     

Acute treatment with MgSO4 attenuates long-term hippocampal tissue loss after brain trauma in the rat

Previous studies have shown that magnesium salts and the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, NPS 1506, attenuated short-term cognitive deficits and histopathological changes associated with traumatic brain injury (TBI). We evaluated the long-term effects of both therapies after brain trauma. Young adult rats were subjected to parasagittal fluid-percussion brain injury and received either MgSO(4) (125 micromol/400 g rat; n = 12) 15 min post-injury, NPS 1506 (1.15 mg/kg; n = 12) 15 min and 4 hr post-injury, or vehicle (n = 9) 15 min post-injury. Uninjured animals (sham) received vehicle (n = 10). Learning function in these animals was evaluated using a water maze paradigm 8 months after injury or sham treatment, and the brains were examined for cortical and hippocampal tissue loss. Compared to sham animals, injured vehicle-treated animals displayed a substantial learning dysfunction, indicated by an increased latency to find a hidden platform in the water maze (P < 0.001). No improvements in learning, however, were found for injured animals treated with NPS 1506 or MgSO(4). Injury induced >30% loss of tissue in the ipsilateral cortex in vehicle-treated animals that was not reduced in animals treated with either NPS 1506 or MgSO(4). Treatment with MgSO(4) significantly reduced progressive tissue loss in the hippocampus (P < 0.001). These findings are the first to demonstrate long-term neuroprotection of hippocampal tissue by an acute treatment in a TBI model. These data also show that the previously reported broad efficacy of MgSO(4) or NPS 1506 observed shortly after brain trauma could not be detected 8 months post-injury.     

Complex time-dependent alterations in the brain expression of different drug efflux transporter genes after status epilepticus

Purpose:   Frequent epileptic seizures or prolonged seizure activity (status epilepticus, SE) is known to increase the brain expression of drug efflux transporter genes and proteins, such as P-glycoprotein (Pgp) and members of the multidrug resistance protein (MRP) family, which might reduce brain levels of antiepileptic drugs and, therefore, be involved in drug resistance. However, the time course of alterations in Pgp or MRPs after seizures or SE is only incompletely known.
Methods:   This prompted us to study the time course of alterations in the expression of different efflux transporter genes (Mdr1a, Mdr1b, MRP1, MRP2, MRP5) at various times after a pilocarpine-induced SE in limbic brain regions, using quantitative real-time polymerase chain reaction (RT-PCR) (qPCR).
Results:   Unexpectedly, between 6 and 24 h after onset of SE, genes encoding Pgp (Mdr1a, Mdr1b), Mrp1, and Mrp5 were downregulated in hippocampus, amygdala, or piriform cortex. This initial decrease in expression was followed by normalization and then increased expression, which became maximal 2 days after SE. One explanation for the initial decrease in transporter expression could be SE-induced acute inflammatory processes, because proinflammatory cytokines are known to suppress the expression of Pgp and other efflux transporters. To directly address this possibility, we quantified the hippocampal mRNA expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α, showing a marked SE-induced increase in these cytokines, which paralleled the decreased expression of efflux transporters.
Discussion:   Taken together, these findings indicate that alterations in expression of drug efflux transporters after prolonged seizure activity are more complex than previously thought.     

大鼠急性局灶性脑挫裂伤后脑微循环研究

目的探讨脑损伤后脑微循环障碍变化规律，为临床改善脑损伤后脑微循环障碍，治疗脑缺血，促进神经功能恢复提供理论依据。方法81只Wistar大鼠随机分为对照组（n=9）和脑损伤组．损伤组按伤后不同观察时相点又分为8个亚组，每亚组9只。采用Feeney’s自由落体撞击法建立急性局灶性脑挫裂伤模型。每组6只行内源性过氧化物酶（EPOD）组织化学染色、脑含水量测定，并进行图像分析。余3只电镜观察微血管内皮细胞超微结构改变。结果（1）脑损伤后30min伤区可见出血灶．伤区内无血管染色．伤区周围存在微无血管区。微无血管区的存在持续至伤后3d。（21脑损伤后30min微血管面密度明显下降，伤后2d达到高峰，直到伤后7d才有所恢复．但仍未达到正常水平。（3）脑损伤后30min微血管平均光密度明显下降，伤后24h、2d回升，3d再次下降，至7d仍未恢复正常。（4）脑损伤后30min，微血管内皮细胞有轻度受损迹象，伤后2h毛细血管腔内有微绒毛形成．伤后6h微绒毛增多。伤后12h～3d毛细血管腔明显狭窄。结论EPOD组织化学染色方法能准确反应脑损伤后脑微循环的改变。脑损伤后即发生脑缺血改变，而脑缺血的发生源于脑损伤后脑微血管结构的破坏和微循环灌注不足。     

Long-term hyperexcitability in the hippocampus after experimental head trauma.

Head injury is a causative factor in the development of temporal lobe epilepsy. However, whether a single episode of concussive head trauma causes a persistent increase in neuronal excitability in the limbic system has not been unequivocally determined. This study used the rodent fluid percussion injury (FPI) model, in combination with electrophysiological and histochemical techniques, to investigate the early (1 week) and long-term (1 month or longer) changes in the hippocampus after head trauma. Low-frequency, single-shock stimulation of the perforant path revealed an early granule cell hyperexcitability in head-injured animals that returned to control levels by 1 month. However, there was a persistent decrease in threshold to induction of seizure-like electrical activity in response to high-frequency tetanic stimulation in the hippocampus after head injury. Timm staining revealed both early- and long-term mossy fiber sprouting at low to moderate levels in the dentate gyrus of animals that experienced FPI. There was a long-lasting increase in the frequency of spontaneous inhibitory postsynaptic currents in dentate granule cells after FPI, and ionotropic glutamate receptor antagonists selectively decreased the spontaneous inhibitory postsynaptic current frequency in the head-injured animals. These results demonstrate that a single episode of experimental closed head trauma induces long-lasting alterations in the hippocampus. These persistent structural and functional alterations in inhibitory and excitatory circuits are likely to influence the development of hyperexcitable foci in posttraumatic limbic circuits.     

急性脑创伤后神经元Caspase 3表达、激活及作用的实验研究

目的 观察急性脑创伤后Caspase3在神经元凋亡中的作用。方法 采用大鼠脑创伤模型，以TUNEL法观察皮层，海马区神经元凋亡；以Northern杂交，原位杂交，免疫组化，Western杂交等对Caspase3在mRNA与蛋白质水平表达和酶活性变化进行观察；通过脑室注射给予Z-DEVD，fmk,观察其对神经元凋亡的治疗作用。结果 大鼠打击后2小时可见TUNEL染色阳性神经元，1天最明显，7天时仍高，Northern杂交和原位杂交显示，皮层，海马区神经元致伤后2小时Caspase3mRNA表达增高，1天最明显，7天仍高于正常，免疫组化法见Caspase3P20亚单位在打击后2小时表达增高，1-3天最明显，可持续至7天，Western杂交显示Caspase3下游底物PARP被降解，脑室内注射Z-DE-VD，fmk可使神经元凋亡减少。结论 急性脑创伤后神经元中Caspase3表达增高，酶活性增强，可导致神经元凋亡，Caspase3特异性酶活性抑制剂能减少神经元凋亡。     

亚低温对大鼠颅脑外伤后脑组织AQP-4和Caspase-3表达的影响

目的观察亚低温治疗对实验大鼠颅脑外伤后水通道蛋白4(AQP-4)和半胱天冬酶3(caspase-3)的影响,探讨亚低温对颅脑外伤后可能的脑保护分子生物机制。方法健康成年雄性Wistar大鼠45只,采用Feeney法建立脑外伤动物模型,随机分为对照组、创伤组和亚低温组,每组15只,亚低温组在损伤后立即给予亚低温暴露,用干湿重法测定脑组织含水量、免疫组织化学法及图象分析技术检测AQP-4和caspase-3及双重染色免疫组织化学法检测AQP-4和S-100。结果与假手术组比较,大鼠颅脑外伤后脑组织AQP-4和caspase-3的表达及脑组织含水量明显升高(P0.05);亚低温治疗后,大鼠脑组织AQP-4和caspase-3的表达及脑组织含水量较脑创伤组明显降低(P0.05)。结论亚低温对创伤性脑损伤的脑保护机制可能与减轻胶质细胞介导的脑水肿,减少神经细胞凋亡有关。     

Compulsive-obsessive disorder after severe head trauma: diagnosis and treatment

An 18-year-old man suffered a severe head trauma from a car accident. Eight months later the patient had a good general state of health. But at this time he was referred to our psychiatric hospital and he reported increased checking compulsions and aggressive obsessions. In addition there was increased impulsivity. The patient was treated with an selective-serotonin-reuptake-inhibitor (SSRI) and showed a clinical response. Obsessive-compulsive disorder (OCD) has rarely been described after traumatic brain injury. Clinical symptoms, neuropsychological dysfunctions, brain imaging and therapy are illustrated. The represented connections of the frontal brain lesions and OCD-symptoms with interventions in the serotonin system support the neurobiological hypotheses of the obsessive-compulsive disorder.