Postinjury administration of L-deprenyl improves cognitive function and enhances neuroplasticity after traumatic brain injury

The rat model of combined central fluid percussion traumatic brain injury (TBI) and bilateral entorhinal cortical lesion (BEC) produces profound, persistent cognitive deficits, sequelae associated with human TBI. In contrast to percussive TBI alone, this combined injury induces maladaptive hippocampal plasticity. Recent reports suggest a potential role for dopamine in CNS plasticity after trauma. We have examined the effect of the dopamine enhancer l-deprenyl on cognitive function and neuroplasticity following TBI. Rats received fluid percussion TBI, BEC alone, or combined TBI + BEC lesion and were treated once daily for 7 days with l-deprenyl, beginning 24 h after TBI alone and 15 min after BEC or TBI + BEC. Postinjury motor assessment showed no effect of l-deprenyl treatment. Cognitive performance was assessed on days 11-15 postinjury and brains from the same cases examined for dopamine beta-hydroxylase immunoreactivity (DBH-IR) and acetylcholinesterase (AChE) histochemistry. Significant cognitive improvement relative to untreated injured cases was observed in both TBI groups following l-deprenyl treatment; however, no drug effects were seen with BEC alone. l-Deprenyl attenuated injury-induced loss in DBH-IR over CA1 and CA3 after TBI alone. However, after combined TBI + BEC, l-deprenyl was only effective in protecting CA1 DBH-IR. AChE histostaining in CA3 was significantly elevated with l-deprenyl in both injury models. After TBI + BEC, l-deprenyl also increased AChE in the dentate molecular layer relative to untreated injured cases. These results suggest that dopaminergic/noradrenergic enhancement facilitates cognitive recovery after brain injury and that noradrenergic fiber integrity is correlated with enhanced synaptic plasticity in the injured hippocampus.     

甘氨酸通过抑制大鼠创伤性脑损伤后炎症反应来发挥神经保护作用

目的 探讨甘氨酸对创伤性脑损伤(TBI)大鼠的神经保护作用及机制。方法 将SD雄性大鼠随机分为对照(Sham)组、脑损伤+溶剂(TBI+Vehicle)组和脑损伤+甘氨酸(TBI+Glycine)组,采用Feeney's自由落体法建立创伤性脑损伤模型; 术后1 h侧脑室注射甘氨酸(2 mg/kg)或等体积的溶剂; 术后24 h,取脑组织样本; 采用脑含水量测定、蛋白免疫印迹法和免疫荧光法评价甘氨酸对大鼠TBI的神经保护作用; 采用ELISA法检测炎症因子白介素1β(IL-1β)、白介素6(IL-6)和肿瘤坏死因子α(TNF-α)的表达水平,评价甘氨酸对TBI后脑组织炎症反应的抑制作用。结果 甘氨酸可减轻TBI后脑水肿,减少皮层神经元损伤; 同时甘氨酸可抑制TBI后炎症因子IL-1β、IL-6和TNF-α的过度释放。结论 甘氨酸对大鼠TBI具有神经保护作用; 甘氨酸对TBI后相关炎症因子过度增高的抑制可能部分解释其神经保护作用机制。     

内脂素改善创伤性脑损伤小鼠神经功能修复的研究

目的研究内脂素对创伤性脑损伤（TBI）小鼠的神经功能保护作用及机制。 方法通过液压冲击方法建立C57BL/6小鼠液压冲击脑损伤模型,共48只,然后随机分为实验组A、实验组B、对照组,各16只。模型建立3 h后起,实验组A和实验组B分别给予腹腔注射内脂素15、30 μg/kg,1次/d,共7 d,对照组给予腹腔注射生理盐水。治疗开始前、开始治疗后第3、14、28天各组随机选取10只小鼠,比较实验组和对照组小鼠的神经功能缺损评分（NSS）;治疗结束后第2天,每组随机取3只小鼠全脑取材,比较TUNEL染色后阳性细胞差异;再随机取3只收集脑组织总蛋白,比较各组小鼠脑组织凋亡相关蛋白水平差异;剩余10只小鼠在治疗结束后第24~28天,比较Morris水迷宫小鼠逃逸潜伏期时间差异。 结果3组小鼠NSS评分在开始治疗后第3天时差异无统计学意义（P>0.05）,但在第14、28天时,内脂素治疗组小鼠NSS评分低于对照组,差异均具有统计学意义（P<0.05）;3组小鼠在治疗结束后24、25 d时水迷宫潜伏逃逸期差异无统计学意义（P>0.05）,但在第26、27、28天时,内脂素治疗组小鼠水迷宫潜伏逃逸期小于对照组,差异具有统计学意义（P<0.05）。内脂素治疗组小鼠脑切片中TUNEL阳性细胞数小于对照组,差异具有统计学意义（P<0.05）,同时凋亡相关蛋白cleave Caspase-3、cleaved PARP的表达量也低于对照组,差异具有统计学意义（P<0.05）。 结论内脂素能够抑制小鼠TBI后病灶周围神经细胞的凋亡及降低凋亡相关蛋白的表达量,改善神经功能的修复。     

Ethyl pyruvate improves white matter remodeling in rats after traumatic brain injury

BackgroundSevere traumatic brain injury (TBI) results in long‐term neurological deficits associated with white matter injury (WMI). Ethyl pyruvate (EP) is a simple derivative of the endogenous energy substrate pyruvate with neuroprotective properties, but its role in recovery from WMI has not been explored.AimsThis study examines the effect of EP treatment on rats following TBI using behavioral tests and white matter histological analysis up to 28 days post‐injury.Materials and MethodsAnaesthetised adult rats were subjected to TBI by controlled cortical impact. After surgery, EP or Ringers solution (RS) was administrated intraperitoneally at 15 min after TBI and again at 12, 24, 36, 48, and 60 h after TBI. Sensorimotor deficits were evaluated up to day 21 after TBI by four independent tests. Immunofluorescence and transmission electron microscopy (TEM) were performed to assess white matter injury. Microglia activation and related inflammatory molecules were examined up to day 14 after TBI by immunohistochemistry or real‐time PCR.ResultsHere, we demonstrate that EP improves sensorimotor function following TBI as well as improves white matter outcomes up to 28 d after TBI, as shown by reduced myelin loss. Furthermore, EP administration during the acute phase of TBI recovery shifted microglia polarization toward the anti‐inflammatoryM2 phenotype, modulating the release of inflammatory‐related factors.ConclusionEP treatment may protect TBI‐induced WMI via modulating microglia polarization toward M2.     

Transplantation of primed human fetal neural stem cells improves cognitive function in rats after traumatic brain injury

Traumatic brain injury (TBI) often produces cognitive impairments by primary or secondary neuronal loss. Stem cells are a potential tool to treat TBI. However, most previous studies using rodent stem or progenitor cells failed to correlate cell grafting and cognitive improvement. Furthermore, the efficacy of fetal human neural stem cells (hNSCs) for ameliorating TBI cognitive dysfunction is undetermined. This study therefore characterized phenotypic differentiation, neurotrophic factor expression and release and functional outcome of grafting hNSCs into TBI rat brains. Adult Sprague-Dawley rats underwent a moderate parasagittal fluid percussion TBI followed by ipsilateral hippocampal transplantation of hNSCs or vehicle 1 day post-injury. Prior to grafting, hNSCs were treated in vitro for 7 days with our previously developed priming procedure. Significant spatial learning and memory improvements were detected by the Morris water maze (MWM) test in rats 10 days after receiving hNSC grafts. Morphological analyses revealed that hNSCs survived and differentiated mainly into neurons in the injured hippocampus at 2 weeks after grafting. Furthermore, hNSCs expressed and released glial-cell-line-derived neurotrophic factor (GDNF) in vitro and when grafted in vivo, as detected by RT-PCR, immunostaining, microdialysis and ELISA. This is the first direct demonstration of the release of a neurotrophic factor in conjunction with stem cell grafting. In conclusion, human fetal neural stem cell grafts improved cognitive function of rats with acute TBI. Grafted cells survived and differentiated into neurons and expressed and released GNDF in vivo, which may help protect host cells from secondary damage and aid host regeneration.     

Improved behavioral outcomes after progesterone administration in aged male rats with traumatic brain injury

Twenty-month-old male Fischer 344 rats with bilateral contusions of the frontal cortex (n=8/group) or sham operations received 16 mg/kg of progesterone or vehicle at 1 and 6 h post-injury, then once every 24 h for the next seven days, with tapering of the dose over the final two treatments. The rats' behavioral recovery was then evaluated on tests of locomotor activity and Morris water maze learning. All rats were sacrificed 21 days post-TBI and brains were perfused and cryoprotected for necrotic cavity measurements. The injury produced significant impairments in activity and spatial learning compared to sham controls. The progesterone-treated rats had better functional outcomes than vehicle-treated rats with similar cortical injuries. The neurosteroid treatment did not affect the size of the necrotic cavity.     

氢盐水对脑创伤后大鼠认知功能的保护作用

目的 观察氢生理盐水对脑外伤后大鼠认知功能的改善作用,并初步探讨其可能机制.方法 应用液压打击损伤装置建立大鼠中度颅脑损伤模型,实验动物随机分为对照组、损伤+生理盐水组、损伤+含氢生理盐水组,采用Morris水迷宫法测定大鼠的认知功能表现;利用分光光度比色法、酶联免疫吸附法和Western blot等方法,分别检测受损同侧海马组织中丙二醛(MDA)、脑源性神经生长因子(BDNF)和突触蛋白Ⅰ的水平,并采用方差分析方法进行统计学分析.结果 Morris 水迷宫法显示腹腔注射含氢的生理盐水能够明显地提高大鼠的认知功能;在对受伤同侧大鼠的海马组织进行测定中,显示损伤后大鼠海马组织中MDA水平的升高及BDNF和突触蛋白Ⅰ水平的下降,而腹腔内注射含氢生理盐水能够明显改善受伤大鼠的认知功能,并能够降低MDA水平,提高BDNF和突触蛋白Ⅰ.结论 腹腔内注射含氢生理盐水能够通过抑制氧化损伤,改善颅脑损伤后动物的认知功能,而BDNF及其效应蛋白突触蛋白Ⅰ可能与其认知功能改善有关.     

轻度低温联合依达拉奉治疗提高重型颅脑损伤疗效

目的 探讨轻度低温联合依达拉奉治疗急性重型颅脑损伤的疗效. 方法 选取自2008年2月至2012年9月在深圳市龙岗中心医院急诊入院的重型颅脑损伤患者共143例,按随机数字表法分为4组:对照组(A组,n=35),给予常规治疗;轻度低温治疗组(B组,n=36),给予常规治疗加轻度低温(33～34℃)治疗,持续时间2～14d;依达拉奉治疗组(C组,n=36),给予常规治疗加依达拉奉30 mg/次,2次/d,连用14d;轻度低温联合依达拉奉治疗组(D组,n=36),给予常规治疗加轻度低温和依达拉奉联合治疗.记录4组患者入院时、入院后24 h、72 h颅内压(ICP)及检测血糖值.治疗后3个月应用格拉斯哥预后评分(GOS)评价疗效. 结果 入院后24 h、72 h时B组、C组平均ICP、血糖值均明显低于A组,D组均明显低于B组、C组,差异均有统计学意义(P＜0.05).D组疗效良好(GOS评分4～5分)率明显优于B组、C组及A组,差异均有统计学意义(P＜0.05). 结论 早期应用轻度低温与依达拉奉联合治疗急性重型颅脑损伤患者的疗效显著优于单纯应用轻度低温或依达拉奉治疗.     

Neuroglobin expression in rats after traumatic brain injury

In this study,we used a rat model of severe closed traumatic brain injury to explore the relationship between neuroglobin,brain injury and neuronal apoptosis.Real-time PCR showed that neuroglobin mRNA expression rapidly increased in the rat cerebral cortex,and peaked at 30 minutes and 48 hours following traumatic brain injury.Immunohistochemical staining demonstrated that neu-roglobin expression increased and remained high 2 hours to 5 days following injury.The rate of in-crease in the apoptosis-related Bax/Bcl-2 ratio greatly decreased between 30 minutes and 1 hour as well as between 48 and 72 hours post injury.Expression of neuroglobin and the anti-apoptotic factor Bcl-2 greatly increased,while that of the proapoptotic factor decreased,in the cerebral cortex post severe closed traumatic brain injury.It suggests that neuroglobin might protect neurons from apoptosis after traumatic injury by regulating Bax/Bcl-2 pathway.     

骨髓间质干细胞移植对大鼠颅脑损伤后氧化应激的影响

目的观察骨髓间质干细胞移植对大鼠外伤性脑损伤的治疗效应和对大鼠颅脑损伤后氧化应激的影响。方法体外分离培养MSCs;建立大鼠TBI模型;经颈内动脉移植MSCs,观察大鼠神经功能的改善状况和两组大鼠脑组织内氧化应激指标的差异。结果MSCs在体外可长期培养扩增,生物学特性稳定;经颈动脉移植4周后,移植治疗的大鼠其神经功能状况改善较好。与对照组相比较,实验组大鼠脑组织内SOD的活性较高,羟自由基的含量较低。结论移植MSCs对TBI所造成的大鼠神经功能缺损有一定的治疗效应。而移植MSCs后能上调脑组织的抗氧化能力,这可能是产生治疗效应的机制之一。     

神经干细胞移植对颅脑外伤神经组织的替代和修复作用

目的 神经干细胞具有自我更新及多向分化潜能的特性。本文将人类神经干细胞移植到大鼠颅脑损伤的模型中，观察是否有治疗效果。方法 人类神经干细胞取自3－4月胎儿海马，体重为300－370g的大鼠制成脑损伤模型，伤后24小时将神经干细胞用立体定向注射法注入双侧顶叶皮层，伤后1周动物运动功能评分后，处死取脑，行病理及免疫组化染色。结果 伤后1周接受干细胞移植的治疗组与损伤组相比呈现出明显的运动功能改善，一部分移植顶叶的干细胞呈Tubulin（＋）、GFAP（＋），表明它们分化成为神经元或胶质细胞。另外我们观察到治疗组伤区皮层的正常神经元增多，且坏死及凋亡的神经元减少。结论 社会干细胞是细胞移植治疗颅脑损伤的一种良好的细胞来源。     

Inhibition of inflammatory cytokines after early decompression may mediate recovery of neurological function in rats with spinal cord injury

A variety of inflammatory cytokines are involved in spinal cord injury and influence the recovery of neuronal function. In the present study, we established a rat model of acute spinal cord injury by cerclage. The cerclage suture was released 8 or 72 hours later, to simulate decompression surgery. Neurological function was evaluated behaviorally for 3 weeks after surgery, and tumor necrosis factor α immunoreactivity and apoptosis were quantified in the region of injury. Rats that underwent decompression surgery had significantly weaker immunoreactivity of tumor necrosis factor α and significantly fewer apoptotic cells, and showed faster improvement of locomotor function than animals in which decompression surgery was not performed. Decompression at 8 hours resulted in significantly faster recovery than that at 72 hours. These data indicate that early decompression may improve neurological function after spinal cord injury by inhibiting the expression of tumor necrosis factor α.     

Cocaine self‐administration is increased after frontal traumatic brain injury and associated with neuroinflammation

Traumatic brain injury (TBI) has been linked to the development of numerous psychiatric diseases, including substance use disorder. However, it can be difficult to ascertain from clinical data whether the TBI is cause or consequence of increased addiction vulnerability. Surprisingly few studies have taken advantage of animal models to investigate the causal nature of this relationship. In terms of a plausible neurobiological mechanism through which TBI could magnify the risk of substance dependence, numerous studies indicate that TBI can cause widespread disruption to monoaminergic signaling in striatal regions, and also increases neuroinflammation. In the current study, male Long‐Evans rats received either a mild or severe TBI centered over the frontal cortex via controlled cortical impact, and were subsequently trained to self‐administer cocaine over 10 6‐hour sessions. At the end of the study, markers of striatal dopaminergic function, and levels of inflammatory cytokine levels in the frontal lobes, were assessed via western blot and multiplex ELISA, respectively. There was significantly higher cocaine intake in a subset of animals with either mild or severe TBI. However, many animals within both TBI groups failed to acquire self‐administration. Principal components analysis suggested that both dopaminergic and neuroinflammatory proteins were associated with overall cocaine intake, yet only an inflammatory component was associated with acquisition of self‐administration, suggesting neuroinflammation may make a more substantial contribution to the likelihood of drug‐taking. Should neuroinflammation play a causal role in mediating TBI‐induced addiction risk, anti‐inflammatory therapy may reduce the likelihood of substance abuse in TBI populations.     

促红细胞生成素对创伤性脑损伤大鼠认知功能影响的实验研究

目的 评价促红细胞生成素(EPO)对脑外伤模型大鼠认知功能的作用,并探讨其影响机制.方法 48只雄性SD大鼠按随机数字表法分为对照组、假手术组、模型组和EPO治疗组.后2组建立液压冲击大鼠颅脑损伤模型,假手术组接受同样的操作但不接受液压冲击,对照组未经任何处理.伤后除EPO治疗组立即腹腔注射EPO(5000 U/kg)2 d外,另外3组同一时间腹腔注射等剂量生理盐水.于外伤后30 d应用Morris水迷官检测大鼠认知功能,伤后37 d应用免疫组化检测脑组织中脑源性生长因子(BDNF)的表达.结果定位航行实验结果显示训练后2、3、4、5 d各组大鼠寻找平台的潜伏期不同,对照组及假手术组潜伏期最短,模型组最长,EPO治疗组介于二者之间,差异有统计学意义(P<0.05);空间搜索实验结果显示各组大鼠在原来平台所在象限游泳时间的百分比不同,对照组及假手术组游泳时间的百分比最高,模型组最低,EPO治疗组介于二者之间,差异有统计学意义(P<0.05);免疫组化染色结果显示EPO治疗组大鼠脑组织BDNF的表达高于另外3组,差异有统计学意义(P<0.05).结论 液压冲击造成的颅脑损伤可损害大鼠的认知功能,外源性给予EPO可以改善外伤后大鼠的空间学习记忆能力,这可能与EPO促进BDNF的表达有关.     

Progesterone administration modulates AQP4 expression and edema after traumatic brain injury in male rats

This study investigates whether progesterone administration regulates AQP4 and GFAP expression in rats with bilateral contusion injuries of the medial frontal cortex. Male rats were given 0 or 16 mg/kg injections of progesterone at 1, 6, 24, and 48 h post-injury. Brains were extracted at 24 h or 72 h post-injury and assayed for cerebral edema and AQP4 and GFAP expression using Western blot analysis. Progesterone treatments reduced brain water content significantly in the brain-injured groups. There was no significant change in AQP4 expression 24 h after progesterone treatment compared to lesion + vehicle animals. However, progesterone significantly reduced AQP4 expression at 72 h post-injury in the tissue bounded by the lateral ventricles and the peri-contusion areas compared to lesion+ vehicle rats, but increased AQP4 expression in the tissue surrounding the third ventricle. Also progesterone effects on GFAP expression varied according to brain region. Our results can be taken to show that the expression of AQP4 protein after TBI is time-dependent, region-specific, and possibly implicated in the formation and resolution of TBI-induced cerebral edema.     

吡格列酮对大鼠创份性脑损伤后炎症因子抑制作用的研究

目的 探讨过氧化物酶体增殖物激活受体-γ(PPAR-γ)及其激活剂噻唑烷二酮类药物--吡格列酮对创伤性脑损伤(TBI)大鼠模型脑组织中正常T细胞活化后表达和分泌的调节蛋白(RANTES)、巨噬细胞移动抑制因子(MIF)表达的影响. 方法成年SD大鼠按照随机数字表法分为正常对照组(10只)、假手术组(10只)、TBI模型组(12只)及吡格列酮治疗组(12只).后两组采用改进的Feeney自由落体脑损伤装置制作TBI大鼠模型.伤后18 h分别给予生理盐水及20mg/(kg·d)吡格列酮治疗:假手术组不进行自由落体致伤,其余步骤同上,术后给与生理盐水治疗;正常对照组不进行任何处理.7 d后收集各组大鼠脑组织,计算脑组织含水量,并采用RT-PCR及Westernblot法检测各组PPAR-γ、RANTES及MIF的mRNA、蛋白表达差异. 结果与对照组及假手术组相比,TBI损伤组大鼠脑组织含水量明显增加,且PPAR-γmRNA表达明显增强,同时RANTES、MIF mRNA及蛋白表达也明显上调;而吡格列酮治疗组大鼠脑组织PPAR-γ的表达进一步增加,RANTES及MIF表达则有所下降. 结论吡格列酮对减轻创伤性脑损伤后持续存在的炎症反应及脑水肿具有一定作用,其机制可能与降低脑组织中RANTES及MIF等炎性细胞因子含量有关.     

吡格列酮对大鼠创份性脑损伤后炎症因子抑制作用的研究

Objective To observe the effects of peroxisome proliferator activated receptor-γ (PPAR-γ) and its activator pioglitazone on the expression of the inflammatory cytokines after traumatic brain injury (TBI) in rats and explore its mechanism. Methods Adult SD rats were randomized into normal control (n=10), sham-operated (n=10), TBI model (n=12) and pioglitazone treatment (n=12) groups. Impact brain injury was induced in the later two groups and 18 h after the injury, normal saline and pioglitazone at the daily dose of 20 mg/kg were given, respectively. The rats in the sham-operated group received identical treatment to the model group but without TBI. Seven days later, the brain tissue was collected and the cerebral water contents were measured. RT-PCR and Western blot were performed to detect the mRNA and protein expressions of PPAR-γ, regulated upon activation normal T cell expressed and secreted (RANTES) and macrophage migration inhibitory factor (MIF). Results Cerebral water content of the TBI model group was markedly increased as compared with that of the control and sham-operated groups (P<0.05). The expressions of PPAR-γ, RANTES and MIF significantly increased after TBI, and pioglitazone treatment resulted in further activation of PPAR-γ but markedly down-regulated RANTES and MIF expressions (P<0.05). Conclusion Pioglitazone offers protective effect against sustained brain edema and inflammation after TBI possibly by lowering the expressions of such inflammatory cytokines as RANTES and MIF in the brain tissue.