MicroRNA在创伤性脑损伤的研究进展

MicroRNA是一类非编码小分子RNA,可调控人类基因组中20%-30%的基因,对细胞分化、增殖和凋亡起着重要调控作用。部分microRNA在哺乳动物中枢神经系统呈高水平表达,在神经元发育、突触发生和可塑性等过程中发挥关键作用,对认知功能亦有重要影响。创伤性脑损伤所致认知障碍的鉴定是法医学领域的重点及难点问题,识别其相关的特异性microRNA及其靶基因、阐明相应的信号传导通路对明确颅脑损伤的诊断、鉴别、预后及判断致伤机制、推断死因等方面可能均具有重要价值,应是今后的研究重点。本文简介microRNA在中枢神经系统中的分布与功能,对microRNA在创伤性脑损伤中所发挥的作用以及法医学研究进展做了重点阐述。     

创伤性脑损伤动物模型研究进展

创伤性脑损伤(traumatic brain injury,TBI)是多因素作用的高度复杂过程,TBI动物实验研究有利于阐明TBI原发性、继发性损伤机制及病理生理学过程,为诊断及治疗提供依据.动物模型的选择依赖于研究目的,然而各种动物模型均具有局限性,仅能复制TBI关键的损伤机制或某一重要的病理生理学过程而无法全面反映...     

大鼠脑外伤后溶酶体酶Cathepsin—B和D的表达

目的研究大鼠脑外伤后溶酶体酶cathepsin-B和-D是否被激活及其不同时段表达变化,阐述其与凋亡执行因子caspase-3表达的关系,并探讨对脑外伤诊断及形成时间的意义。方法采用自由落体打击法建立脑外伤动物模型,并对模型及对照样本进行免疫荧光、双标和激光共聚焦检测,结果用SPSS10.0软件处理。结果脑外伤后1hcathepsin-B表达即增加,4～8d达高峰,脑外伤后32d仍处于高表达水平;cathepsin-D的表达于脑外伤后12h增加,4～8d达高峰,32d的表达仍然高于12h的表达水平。脑外伤初期,cathepsin-B和-D阳性细胞与caspase-3阳性细胞重叠较少,脑外伤后6h开始增加,32d仍然有很多阳性细胞重叠。结论脑外伤后cathepsin-B和-D被激活,其激活在脑外伤早期可能抑制细胞凋亡执行因子caspase-3的激活,之后(6h后)则与caspase-3起协同作用,共同促进细胞死亡;cathepsin-B和-D表达的时程变化对于脑外伤的法医学诊断和中晚期的时间推断有参考意义。     

载脂蛋白E与脑损伤的研究进展

载脂蛋白E(apolipoprote in E,apo E)在脑损伤愈后过程中起着重要的作用,在损伤后不同时段,apo E含量及出现部位均呈现一定的波动性,而这些问题对探讨脑损伤的治疗及在法医学中推断脑损伤时间有十分重要的意义。本文现就这些问题的相关研究作一概述。     

大鼠脑外伤后大脑皮质脑红蛋白的定量研究

目的探讨脑外伤后大脑皮质脑红蛋白(Ngb)随时间变化的规律及其法医学意义。方法自由落体硬膜外撞击法复制大鼠中度颅脑损伤模型,采用免疫组化方法和图像分析技术观测脑外伤后不同时间损伤区大脑皮质、损伤周半影区以及损伤对侧皮质的Ngb免疫组化反应及其阳性信号灰度值和阳性信号面积,并对所测数据进行统计学分析。结果脑外伤后大鼠损伤区大脑皮质Ngb阳性反应细胞迅速减少,伤后24h降至最低,至16d维持在较低水平;损伤周半影区Ngb阳性反应细胞迅速增加,伤后12h达高峰,随后逐渐减少,至8d及16d恢复至正常水平;损伤区大脑皮质Ngb阳性信号低于对侧大脑皮质,损伤周半影区Ngb阳性信号强于对侧皮质。结论脑外伤后大鼠大脑皮质Ngb阳性反应细胞随时间延长呈现区域性的增多或减少。     

创伤性脑损伤后生物分子标志物的研究进展

创伤性脑损伤(traumatic brain injury,TBI)是指机械性外力作用于头部时发生的损伤,导致一个或者多个病变,如颅内损伤、神经病学或者神经心理学改变、意识障碍或者死亡。TBI可因直接打击、缺血缺氧性脑损伤、炎性介质、细胞因子及氧自由基等机制诱发神经元死亡。TBI发生发展过程中产生了大量生物分子标志物,深入研究TBI后生物分子标志物的变化及其规律,对法医学鉴定及临床治疗都有重大意义。本文结合相关文献概述了TBI相关生物分子标志物的研究进展,为寻找更精确的与TBI诊断相关的生物分子标志物提供参考依据。     

Long-term intracerebral inflammatory response after traumatic brain injury

Epidemiological and pathological studies suggest that head injury is a significant risk factor for subsequent neurodegeneration and cognitive decline in later life. The precise mechanisms for the development of post-traumatic neurodegenerative change are unclear but we hypothesize that persistence of inflammatory processes in the brain may play a key role and that some individuals are more susceptible to such changes based on their genetic make-up. In support of this hypothesis we present evidence of persistent elevated microglial activity in long-term survivors of head injury and the suggestion of an association between the extent of this activity and interleukin-1 genotype.     

GFAP和VEGF在创伤性脑损伤中表达的研究进展

创伤性脑损伤是世界上导致死亡及残疾的主要原因之一。检测对中枢神经系统损伤有高度特异性和敏感性的生物标志物,可以在一定程度上反映损伤情况。胶质纤维酸性蛋白与血管内皮生长因子均可作为颅脑损伤的生物学标记物,其表达变化规律、峰值出现时间,与创伤性脑损伤的严重程度及损伤时间的推断密切相关,对于法医病理学具有重大意义。该文对胶质纤维酸性蛋白与血管内皮生长因子的分子生物学特性及其在创伤性脑损伤中的表达进行综述。     

酒精相关颅脑损伤研究进展

酒精暴露常见于颅脑损伤(traumatic brain injury,TBI)的发生过程中,与颅脑损伤死亡具有紧密联系。国内外此方面研究纷繁复杂。本文总结了近十年相关国内外实验研究,从临床实验研究、动物模型应用、脑损伤鉴别不同方面对不同血清酒精水平(blood alcohol concentration,BAC)对于颅脑损伤影响相关研究进展进行系统阐述。本综述为进一步相关研究提供参考,也对相关死亡案件鉴定具有借鉴意义。     

核因子-κB及其在创伤性脑损伤后的作用

核因子-κB是一种具有多向性调节作用的核转录因子.机体受到创伤后,NF-κB被激活,调节多种炎性介质基因转录,引起局部及全身的炎症反应.对NF-κB的有关研究可望用于法医学家对损伤时间的推测.     

核因子-кB及其在创伤性脑损伤后的作用

核因子-кB是一种具有多向性调节作用的核转录因子。机体受到创伤后,NF-кB被激活,调节多种炎性介质基因转录,引起局部及全身的炎症反应。对NF-кB的有关研究可望用于法医学家对损伤时间的推测。     

Immunohistochemical research on brain stem injury: expression of heat shock protein 70 in rat brain after traumatic brain stem injury

The aim of this study was to determine the expression of heat shock protein 70 (HSP70) as molecular chaperones, following traumatic brain stem injury(TBSI). The expression of HSP70 was detected in respective brain regions of rats 1 h, 3 h, 6 h, 12 h, 24 h after brain stem stabbing wound. Numerous HSP70 immunoreactivity positive blood vessel endothelioid and glia cells were found in cerebral, cerebellar cortex and hippocampus after 1 h, with H.E stain unchanged. In the area near the focal of brain stem injury, HSP70 immunoreactivity positive neurons increased significantly after 1 h of injury, reaching the highest level after 3 h, much higher than in other areas. HSP70 immunoreactivity positive cells still existed after 24 h of injury. It was suggested that TBSI cause the defectiveness of protein structure in brain, and induce HSP70 proteolysis of denature protein including misfolding or aggregate. TBSI can be diagnosed regionally by the increasing of HSP70 immunoreactivity positive neurons in the focal of brain stems.     

NMDA-Ca2+-NO路径与继发性脑损伤

当前,对NMDA-Ca2+-NO路径的研究仍是神经科学、生理学和生物化学研究的一个热点。从法医学角度研究该路径的意义在于,该路径能揭示出脑损伤所始发的胞外有害刺激是以何种可能方式逐步传导入损伤波及区域的神经元(细胞)内,并最终产生损害或致其死亡的。对该路径的研究可以为法医学上鉴定脑损伤后的经过时间、脑伤程度及判断预后提供分子水平的解释。     

颅脑损伤后动态姿势平衡评估

目的探讨颅脑损伤后平衡功能障碍的特点和原因。方法对95例交通事故致颅脑损伤的患者进行动态姿势图检查,将其测试结果与正常值比较;并按照原发颅脑损伤程度和是否伴有听力障碍对患者进行分组,将测试结果进行组间比较。结果颅脑损伤患者平衡总分较正常值低,对视觉和前庭觉等信息的利用能力下降,以前庭觉下降明显;原发颅脑损伤的严重程度以及是否伴听力下降对姿势稳定性无明显影响。结论不伴有肢体功能障碍的颅脑损伤患者的姿势稳定性差,对环境的反应与适应能力下降,可能与外周前庭器官及平衡中枢的损伤有关。     

颅脑损伤致精神障碍的法医学鉴定

本文综述了国内外颅脑损伤致精神障碍的相关法医学现状,特别是对于鉴定中的常见问题进行了简要的综述。     

实验大鼠轻中型闭合性脑损伤昏迷指标与分级标准

目的为使实验室间的研究数据可比,特建立大鼠轻型和中型闭合性脑损伤分级的昏迷量化标准。方法利用自制金属单摆装置复制大鼠脑损伤动物模型,按照大鼠脑损伤后昏迷反应程度进行呼吸暂停时间,角膜反射、外耳道刺激反应、翻正反射及针刺疼痛反应消失后恢复时间的实际测量与评分,结合肉眼颅脑解剖检查进行验证,对前述指标的实测值和评分赋值数据进行多元判别回归分析,建立判别方程。结果应用实测值和评分值进行轻型脑损伤判别的概率分别是88.9%和91.9%。结论该标准是一个较理想实用的大鼠轻、中型脑损伤分级标准。     

The expression of excitatory amino acid transporter 2 in traumatic brain injury

It is well recognized that glutamate is the major excitatory neurotransmitter, which is removed from the synaptic cleft by excitatory amino acid transporter 2 (EAAT2) located on the perisynaptic astrocytes and that neuronal death has been associated with an increased extracellular glutamate concentration. In this study, we have immunohistochemically demonstrated the expression of EAAT2 protein in the human brain after traumatic brain injury (TBI). The EAAT2 expression patterns can be divided into three types: continuous and highly extensive staining (E); continuous but sporadic staining (M); and sporadic pattern staining (S). In six of the nine short survival cases studied (1 h to 1 day), continuous and highly extensive staining for EAAT2 (E type) was observed in the ipsilateral cerebral cortex. On the other hand, we were able to demonstrate weak staining (S and M types) in 5 of the 7 long survival cases (≥1 day) and in 12 of the 14 very short survival cases (<1 h) studied. Similar findings were obtained in the contralateral cerebral cortex and also in the ipsilateral hippocampus. In addition, positive staining for glial fibrillary acidic protein was detected around the cerebral contusion, but the EAAT2-positive expression was not observed in the same region for all of the six short and long survival cases (≥1 h) after TBI. These findings clearly showed the differences in EAAT2 expression in the cerebral cortex according to the survival time and severity of cerebral contusion after TBI. Therefore, we emphasized that EAAT2 might play an important role in contributing to extracellular glutamate concentrations and secondary brain injury after TBI.     

The expression of excitatory amino acid transporter 2 in traumatic brain injury

It is well recognized that glutamate is the major excitatory neurotransmitter, which is removed from the synaptic cleft by excitatory amino acid transporter 2 (EAAT2) located on the perisynaptic astrocytes and that neuronal death has been associated with an increased extracellular glutamate concentration. In this study, we have immunohistochemically demonstrated the expression of EAAT2 protein in the human brain after traumatic brain injury (TBI). The EAAT2 expression patterns can be divided into three types: continuous and highly extensive staining (E); continuous but sporadic staining (M); and sporadic pattern staining (S). In six of the nine short survival cases studied (1 h to 1 day), continuous and highly extensive staining for EAAT2 (E type) was observed in the ipsilateral cerebral cortex. On the other hand, we were able to demonstrate weak staining (S and M types) in 5 of the 7 long survival cases (> or =1 day) and in 12 of the 14 very short survival cases (<1 h) studied. Similar findings were obtained in the contralateral cerebral cortex and also in the ipsilateral hippocampus. In addition, positive staining for glial fibrillary acidic protein was detected around the cerebral contusion, but the EAAT2-positive expression was not observed in the same region for all of the six short and long survival cases (> or =1 h) after TBI. These findings clearly showed the differences in EAAT2 expression in the cerebral cortex according to the survival time and severity of cerebral contusion after TBI. Therefore, we emphasized that EAAT2 might play an important role in contributing to extracellular glutamate concentrations and secondary brain injury after TBI.     

创伤性脑损伤大鼠水通道蛋白4表达变化及法医学意义

目的观察大鼠颅脑损伤后不同时间内水通道蛋白4（AQP4）mRNA表达的变化，探讨AQP4在脑损伤经过时间推断中的意义。方法利用液压冲击法制作不同程度大鼠颅脑损伤模型，在伤后不同时间（0．5、2、6、12、24、48、72h），应用RT-PCR法检测脑组织AQP4 mRNA表达，同时以非损伤组做对照。结果不同程度颅脑损伤后0．5h脑组织AQP4 mRNA表达均开始上调（P〈0．01），6、12h依次增高，24h达到高峰，差异均有统计学意义（P〈0．01），72h时仍维持较高水平（P〈0．01）；0．5h时轻度、中度、重度脑损伤时AQP4 mRNA的表达差异两两之间无统计学意义（P〉0．05），2、6、12、24、48、72h轻度、中度、重度脑损伤时AQP4 mRNA的表达差异两两之间有统计学意义（P〈0．01）。结论颅脑损伤后AQP4 mRNA呈现出时序性变化，其变化规律可望成为法医学推断早期脑损伤时间的指标之一。     

大鼠实验性脑挫伤后不同时间脑apoE的表达

目的观察大鼠实验性脑挫伤后脑内apoE蛋白变化的时空性规律。方法采用自由落体撞击法致大鼠脑挫伤模型,观察伤后不同时间(0.5h、2h、6h、12h、24h、3d、7d、14d)apoE蛋白的变化,并用计算机图像分析技术作定量统计分析。结果伤后0.5h组脑皮质神经元apoE出现阳性表达,3d达到高峰,随后下降;伤后0.5h组在海马出现apoE强阳性反应,CA1区在伤后3d达到高峰,而CA2~CA4区在24h达到高峰,随后逐渐下降,伤后海马apoE表达以CA1区最强。结论挫伤后apoE时空性变化规律可作为脑损伤时间推断、早期诊断及生前伤和死后伤鉴别的一个新的参考指标。