大鼠闭合性脑损伤扫描电镜观察

用扫描电镜观察大鼠闭合性脑损伤后直接致死及伤后１５分钟至伤后５天处死的大鼠脑组织形态学改变,发现大鼠脑震荡性损伤后病变主要为：全脑弥漫性神经纤维排列紊乱、扭曲、波浪状变形和断裂;髓鞘脱落或套袖样剥离;轴索肿胀;轴索断端收缩球形成;神经纤维表面颗粒状隆起（芽生现象）;神经细胞球形肿胀;神经细胞膜穿孔状破裂;神经细胞膜表面突触脱失或减少;脑实质血管壁破裂穿孔。神经纤维的各种改变均随伤后存活时间的延长而加重,其中轴索收缩球于伤后８ｈ出现,直径约为３～５μｍ,伤后３～５天可达７～８μｍ。损伤多见于额叶和顶叶、皮质－白质交界区、胼胝体和内囊区,尤以脑干为重     

IL-1β和TNF-α在大鼠弥漫性轴索损伤中的作用

目的观察大鼠弥漫性轴索损伤后IL-1β和TNF-α蛋白表达的时序性变化,探讨其在大鼠弥漫性轴索损伤（diffuse axonal injury,DAI）中的作用。方法 55只健康雄性SD大鼠,随机分为正常对照组、手术对照组和DAI组,采用HE、Gless氏嗜银染色和免疫组织化学（SP法）观察不同时间（30min～7d）脑干组织病理学改变及IL-1β和TNF-α蛋白的表达情况。结果 HE染色显示DIA大鼠脑干组织结构疏松、水肿,Gless氏嗜银染色可见轴索肿胀、扭曲、收缩球形成等改变,证明弥漫性轴索损伤模型成功;IL-1β和TNF-α在正常对照组与假手术组大鼠脑干神经元内有低表达,而在DAI后30min～6h大鼠脑干神经元和小胶质细胞内表达迅速增加,于6h达高峰。结论大鼠弥漫性轴索损伤后IL-1β和TNF-α蛋白在脑干内表达的增加,与轴索继发性损伤有关。     

人脑挫伤后神经丝蛋白NF200表达的变化

目的研究人脑挫伤后NF200在脑组织中神经元及轴索中表达的变化。方法88例闭合性脑挫伤标本,按损伤时间分为0.5h、1h、3h、24h、3d、7d、14d和30d共8个实验组,另以6例非脑挫伤的脑作为对照组,应用NF200免疫组织化学染色,结合图像分析技术,观察伤后不同时间NF200的变化。结果脑挫伤后0.5h和1h组,挫伤灶内及边缘NF200免疫组化染色几乎阴性;随时间的延长,挫伤灶内残存神经元及其周围神经元NF200染色逐渐增强,甚至发生核内转移;挫伤灶周围轴索在伤后出现波浪状扭曲、肿胀和断裂,最早在24h组出现收缩球(retractionball,RB),7d组轴索病变最明显,可见大量RB。图像分析发现伤后0.5h组和1h组,脑挫伤部位NF200阳性细胞的平均光密度(AOD)下降,其后逐渐升高,在14d组或30d组达高峰。结论脑损伤后NF200变化有一定规律性,并可用于诊断轴索损伤(AI),免疫组织化学结合结合图像分析技术在推断脑损伤时间上的有一定参考价值。     

实验性脑弥漫性轴索损伤的组织病理学变化

目的探讨钝力致脑弥漫性轴索损伤(DAI)的法医病理学鉴定依据。方法采用液压冲击方法建立钝力致家猫脑DAI模型;通过H．E．、Bodian、Kluver-Barrera普通组织化学染色及NF免疫组化染色,观察致伤后不同时间脑实质内轴索及其髓鞘的变化,并通过图像分析系统对轴索内NF免疫组化染色阳性反应物面积进行定量检测,所得数据用SPSS 11．5 for Windows软件进行统计学分析。结果致伤后1-2h,猫大脑皮质下白质、胼胝体及脑干轴索轻度肿胀、弯曲;4h轴索肿胀、弯曲显著,呈断续状,且在胼胝体、丘脑及脑干出血区周围出现收缩球,髓鞘开始疏松崩解。随着观察时间的延长,收缩球进一步变大,中心空泡出现,髓鞘疏松、水肿、崩解。经对轴索内NF免疫组化染色阳性反应物的图像分析数据进行统计学分析,对比组间差别具有非常显著性差异意义(P<0．01)。结论脑轴索肿胀、弯曲、增粗、离断以及收缩球的形成,是DAI法医病理学鉴定的依据。     

脑干损伤后神经元及轴突改变的组织化学观察

采用针刺法造成大鼠脑干损伤,用尼氏体染色、嗜银染色和改良三色法观察脑干神经元及轴突在伤后不同时间的病理改变。结果发现,嗜银染色显示伤后 1～ 3h部分神经纤维不规则增粗、少数断裂, 6h断端膨大呈球形, 15h收缩球较为明显,至 24h收缩球明显且数量增多;改良三色法显示伤后 3～ 6h部分髓鞘与轴突之间的间隙增宽, 15h髓鞘明显弯曲、不完全地附着在轴突表面,甚至剥脱,持续到伤后 24h;尼氏体染色显示神经元核周尼氏体在伤后 24h减少。该结果提示,组织化学染色能观察到脑干损伤后的病理改变,并且有可能用于推断脑干损伤时间。     

大鼠闭合性弥漫性脑损伤脑血管铸型的扫描电镜观察

用扫描电镜观察闭合性脑损伤即刻致死和伤后15min大鼠脑血管铸型，发现大鼠脑震荡性损伤后，脑干穿行小动脉及其分支可见多数散在的微动脉痉挛，呈节段性变细，扭曲，血管腔直径约2—5mp。毛细血管前括约肌收缩。正常大鼠脑干实质小动脉直径约10~15mp。讨论了外伤性脑血管痉挛的机制及其对颅脑损伤后果的影响。     

大鼠脑震荡模型的建立及病理学研究

本文介绍用单摆式打击装置建立大鼠脑震荡模型。意识丧失1～6分钟,并迅速恢复而无定位性神经病学征象。打击时鼠头部吸收能量约2.35J。常规病理学检查发现脑组织有淤血、水肿和灶性出血。病变有明显的时序:脑震荡后15分钟脑血管痉挛;1小时开始出现淤血,水肿;6小时病变达到高峰,可见散在小出血灶;24小时恢复至1小时水平;48小时基本正常。Woil氏染色,显示弥漫性轴索、髓鞘肿胀;伤后6小时开始出现“收缩球”。病变以脑干、枕极、小脑、额极、海马及脑室壁等中线区为重。     

闭合性颅脑损伤后大鼠BAEP及脑损伤的动态变化

目的观察大鼠闭合性弥漫性颅脑损伤后脑干听觉诱发电位(BAEP)的动态改变及脑组织病理学变化,探讨BAEP在颅脑损伤后评估听觉功能障碍的价值。方法使用自制弹簧式小型生物打击机打击大鼠颅顶部,制造闭合性弥漫性轻型颅脑损伤模型。观察对照组以及伤后15min和1,3,6,12h及1,2,4,7,10,14,21d等时间点大鼠脑组织病理学改变,干/湿法检测脑组织含水量。分别于伤前、伤后各时间点以50Hz刺激率记录大鼠BAEP,对其结果进行比较。结果损伤后15min,BAEP的Ⅰ～Ⅴ、Ⅲ～ⅤIPL即较损伤前延长(P<0.05),至6～12h,Ⅲ、ⅤPL较损伤前延长。损伤后1～2d,Ⅲ、ⅤPL和Ⅰ～Ⅲ、Ⅰ～Ⅴ、Ⅲ～ⅤIPL均较损伤前显著延长(P<0.001),14d后BAEP逐渐恢复正常。伤后15min脑组织含水量开始升高,伤后1d达高峰,持续至4d后逐渐下降,至10d后降至正常水平。结论BAEP可作为闭合性弥漫性轻型颅脑损伤后听觉功能障碍的客观评价指标。     

头外伤短时死亡者脑干组织学改变的观察

ＨＥ染色,光镜下观察皮质挫伤及脑干损伤的形态学改变,在脑损伤组可见出血、水肿及神经元坏死等。可疑脑干损伤组也可见上述改变。     

单纯性神经纤维撕裂性损伤活体检验1例

神经纤维撕裂性损伤,也称轴索损伤,可与严重的脑挫裂伤、脑深部出血、脑干血管损伤同时发生,也可单独出现。在一些闭合性颅脑损伤的尸体检验中,发现在大脑的白质、胼胝体、内囊、第三脑室周围灰质、脑干上部背外侧、大脑脚等部位有弥散性轴索损伤,当此种损伤与其它脑损伤合并存在时,极易被遗漏掉,从而被诊断为脑挫裂伤或脑出血等症。如为单纯性神经纤维撕裂性损伤,则极易被认为“临床检验未见明显病变”,而无法解释其临床症状,做出误诊。     

The SEM observation of brain tissues and vascular corrosion cast of closed diffuse brain injuries

The morphologic changes of the closed injured brain of rats were observed by SEM. The rats either died immediately after conclusive injuries or were killed after 5 minutes to 5 days after injuries. The main changes were as follows: the diffuse disorder, twist, wave-like distortion and break of neuron fibers; axonal swelling; formation of axonal retraction balls; stripping and denotation of myelin sheath The ball-like swelling of neuron, break of neuron membrane and vascular wall, and microthrombus formations were also observed. These damages worsened with prolongation of surviving time of the rats. The axonal retraction ball appeared 8 hours after the injury and was approximately 3-5 cm in diameter, and developed to 7-8 cm after 3-5 days. It is observed that frontal lobe, cerebellum and brain stem were severely damaged.     

Diffuse axonal injury

Diffuse axonal injury is a distinct form of head injury, induced by direct external forces at the time of the trauma, and not produced by secondary changes due to a primary injury. This type of lesion may be without conspicuous findings on gross brain examination, or may be found with coexisting conventional types of brain injuries. It is characterized by diffuse retraction balls (axonal swellings), hemorrhage or laceration of the corpus callosum, and hemorrhages in the brain stem. It is of utmost importance for forensic pathologists to be aware of this little-recognized entity. Five illustrative cases are presented.     

豚鼠脑震荡实验模型的建立和形态观察

实验用健康豚鼠46只,予以编号。用暴力撞击头部,建立脑震荡的动物模型。30只动物出现昏迷,于数分钟內恢复正常,无感觉和运动后遗症。分别于3、6、12、24、48、72h,1、2、3、4周处死。肉眼观察脑表面无异常,光镜和电镜下,72h以内各组胼胝休和脑干传出传入纤维轴索肿胀成串珠状或断裂成节段形,髓鞘崩解。其中24、48h有数量不等的巨噬细胞浸润;银染色可见轴索断端有收缩球。大脑皮质神经细胞部分有缺血固缩或肿胀变性,尼氏体溶解及卫星现象。血管反应及胶质细胞增生,偶见结节。伤后1～4周反应逐渐减轻。其余16只动物有不同部位的脑组织挫伤。对照组7只动物无上述阳性发现。     

大鼠弥散性轴索损伤后β-APP的表达

目的观察大鼠DAI损伤后β-APP表达和Gless神经纤维轴索染色在诊断DAI损伤及判断损伤时间的价值。方法按Marmarou法复制大鼠DAI损伤模型,脑组织常规取材后进行β-APP及Gless氏神经纤维轴索染色观察。结果β-APP及Gless氏染色法在大鼠DAI损伤后0.5h即可见神经轴索断裂、扭曲变形、增粗膨大,12h以后可见到轴索收缩球。二种方法均显示DAI损伤的病理形态学变化,伤后12h明显,1d达到高峰,3d后开始修复,10d后基本恢复正常。β-APP表达强度在实验组不同时间存在着明显的差异,即3h呈明显阳性表达,1d达到高峰,3d后逐渐减弱,10d基本恢复正常。结论β-APP免疫组织化学染色法及Gless氏神经纤维轴索染色法,对DAI的早期诊断具有重要应用价值,并能从病理形态学上反映DAI损伤的时序性。β-APP表达强度变化是推断早期DAI损伤时间的重要参考指标。     

Application of diffusion tensor imaging and 1H-magnetic resonance spectroscopy in diagnosis of traumatic brain injury

Mild traumatic brain injury (mTBI) is a common type of brain disorders among young adults. The dysfunction of the brain is often exacerbated due to diffuse axonal injury (DAI) which based on the injury of white matter fibers and axons. Since mild and moderate brain injury or DAI are diffuse and subtle, conventional CT and MRI are difficult to make a positive diagnosis. Recent clinical study indicated that functional magnetic resonance imaging has a high detection rate in the diagnosis of acute mild and moderate brain injury, especially the diffusion tensor imaging (DTI) and 1H-magnetic resonance spectroscopy (1H-MRS). This paper has reviewed the principles and characteristics of DTI and 1H-MRS, and recent research in the clinical and animal experiments on brain injury.     

实验性大鼠弥漫性轴索损伤的傅里叶红外光谱检测

目的探讨利用傅里叶红外光谱技术诊断弥漫性轴索损伤的可行性。方法利用HE染色、银染和β-APP免疫组化染色确认大鼠弥漫性轴索损伤模型,利用傅里叶变换显微红外光谱面扫描成像技术检测弥漫性轴索损伤区域酰胺Ⅱ带的光谱分布情况,得到弥漫性轴索损伤的红外光谱数据,绘制红外光谱病理图像。结果实验组与对照组的酰胺Ⅱ带红外光谱吸收度之间存在明显差异,红外光谱病理图像中酰胺Ⅱ带的高吸收区与弥漫性轴索损伤区符合。结论傅里叶红外光谱技术可对弥漫性轴索损伤进行病理形态学诊断。     

White matter damage following acute head injury

The study of a series of brains from patients who had a severe head injury and died within 72 h without a lucid interval showed that there was a step-wise progression in the development of retraction balls. At 2 h after injury sinusoidal enlargement of the axons was evident. This progressed over 16 h when the lesions appeared as retraction balls which were fully developed at 72 h. There was a similar increase of staining with an immunoperoxidase method for glial fibrillary acid protein (GFAP) initially around blood vessels spreading diffusely into the white matter. The number of reactive astrocytes also increased. In a control case where the corpus callosum was torn at post-mortem there were sinusoidally distended and torn axons in the absence of GFAP staining. It is proposed that there are three components to a head injury. First, mechanical injury as seen in the control case; second, the development of retraction balls which are an active process probably representing damaged axons which cannot undergo repair where the sinusoidal swellings develop into retraction balls and third, an astrocytic reaction. The sinusoidal change, when present on its own, may not be separable from post-mortem trauma. However, when it is associated with an astrocytic response it should be correlated with coma in the same way as retraction balls.