我们感谢R. Gettens，N. St. Johns，P. Bennet和J. Robson对TBI模型的发展所做的贡献。来自大脑与行为研究基金会（F.P.和M.J.R.）的NARSAD青年研究员资助，来自Darrell K. Royal阿尔茨海默病研究基金会（F.P.）的研究资助和PhRMA基金会奖（M.J.R.）支持这项研究。这项工作得到了美国药物教育基金会（A.F.L和B.P.L.）的博士前奖学金的支持。

该协议遵循辛辛那提大学和西弗吉尼亚大学的动物护理指南。所有涉及动物的程序均由 机构动物护理和使用委员会 （IACUC）批准，并根据" 实验动物护理和使用指南"的原则进行。
1. 安装抛丸TBI设置
<ol><li>获取设置所需的所有工作部件，包括:由钢制驱动和驱动部分组成的减震管，聚酯膜，固定螺栓，压力传感器，聚氯乙烯（PVC）管道护罩以保护外围器官，9.53 mm高压液压管路和快速连接公母附件，高流量气体调节器和带壁挂支架的气瓶（见 图1A，B 和 材料表）。 注:此处使用的驱动和驱动部分的规格（见 图2 和 材料表）已经建立，以产生一致的短持续时间缩放冲击波（见 图3C，D），以诱导小鼠轻度至中度TBI。为此，选择了锥度设计（6°锥度）短驱动器部分。可以修改从动段和驱动段的长度和直径，以专门研究冲击波29、30、31、32、压缩波18或冲击波动力学33。对于大鼠实验，需要调整减震管的尺寸，以根据保留相关的身体缩放参数17 产生可比的力（见 材料表）。</li>
	<li>将装置的各个工作部件安装在机器滑动台上，这些滑动台固定在经批准用于动物实验的实验室空间中稳定，易于清洁的表面上（最好是用于啮齿动物的不锈钢）。 注:冲击波实验会产生相当程度的噪声;因此，选择吸音实验室空间内的位置，噪音不会干扰其他实验/实验室组。<ol>
<li>将PVC管护罩垂直于防震管装置固定，以便啮齿动物的身体被完全覆盖，只有头部突出。 注意:对于此处描述的诱导轻度至中度TBI的标准程序，头部的中心位于小鼠驱动部分末端5厘米处。</li>
		<li>壁挂式气瓶，靠近设置，符合OSHA和所有其他相关安全法规。 注:在啮齿动物冲击管型号中，压缩空气、氦气或氮气通常用于产生爆炸波。这里提供的所有数据都是使用氦气生成的，因为这种气体在较短的持续时间内产生更高的超压34，从而允许小鼠受试者进行适当的缩放。</li>
	</ol>
</li>
</ol>2. 使用压力传感器记录评估设置和冲击波属性。
<ol><li>准备减震管。<ol>
<li>小心地切割聚酯膜，不要弯曲并产生裂缝，以确保一致的破裂。</li>
		<li>将薄膜插入从动部分和驱动器部分之间。通过拧紧连接螺栓固定各部分。</li>
		<li>检查系统是否气密，并且膜在驱动器和驱动部分之间是否紧密固定。</li>
		<li>通过 9.53 mm 高压液压软管连接气罐，并将附件快速连接到减震管 注:驱动器和从动部分加工成精确的公差，以便在各部分之间提供膜的完全密封。这允许没有气体泄漏，并排除使用任何形式的垫片/O形圈材料，并允许在生成的波形中具有更高的一致性。</li>
	</ol></li>
	<li>安装压力传感器以监测爆炸波（见 图1C）。<ol>
<li>将一个压力传感器放置在头部放置区域，将三个传感器放置在减震管的出口处（见 图1C 和 2）。</li>
		<li>在执行冲击波之前，从压力传感器开始记录。使用传感器信号调理器和数据采集板以每秒500，000帧的速度记录压力波数据（见 材料表）。 注意:佩戴OHSA批准的耳罩，以确保足够的听力保护。</li>
		<li>完全打开压缩气罐的主阀，让气流产生突然、快速的压力峰值。 注意:气体超压使聚酯膜破裂，释放冲击波，冲击波在驱动部分内转变为压缩波，并沿着头部放置区域的方向离开管子。</li>
		<li>手术后立即关闭气流。 注:该装置可配备弹簧复位阀，以自动快速停止气体流量。</li>
		<li>使用自定义的书面计算机程序分析压力波记录，以确定峰值超压和图形数据。数据可以与每个传感器单独绘制或相互叠加，以显示所产生波的平面性（见 图3C，D）。 注:从技术上讲，可以使用更易于使用的软件进行分析，但由于数据集较大，这些程序在生成绘图方面存在长时间的延迟。</li>
	</ol></li>
	<li>建立足以实现指定TBI研究目标的实验条件，并确认该模型产生一致的冲击波，其峰值过压，持续时间和脉冲测量与弗里德兰德波相当（见 图3）。使用上述计算机软件验证这些参数。<ol>
<li>通过重复步骤 2.1.1 来校准设置。到 2.2.5。并使用压力波记录来确定设置是否需要调整（有关代表性数据，请参见 图3）。</li>
		<li>修改设置（如果需要）。 注:抛波属性可通过对设置进行细微修改进行调整。例如，头部到驱动部分末端的距离会影响头部水平的冲击波力。聚酯膜的厚度决定了峰超压的水平，较厚的膜增加峰水平（见 图3A，B）。此外，该设置允许选择冲击波撞击/穿透头部的方向（即正面，侧面，顶部或下方），因此可以研究不同的方面，例如单独或与政变和由于快速旋转力引起的冲击波伤害相结合。</li>
		<li>重复步骤2.1.1至2.2.4，以确定所需的冲击波特性（如果需要）并控制再现性。</li>
		<li>使用不同厚度的聚酯膜重复步骤2.1.1至2.2.4，以评估设置的可扩展性（代表性数据见 图3A，B）。</li>
	</ol></li>
</ol>3. 啮齿动物轻度TBI的实验设置和诱导的准备
注意:在TBI实验开始前30分钟至1小时将啮齿动物转移到保持区域以适应环境。选择受手术噪音影响最小的保持区域。
<ol><li>准备实验所需的所有材料，并检查设置是否正确安装（例如，根据研究目的调整参数）（〜5 - 10分钟）。 注意:损伤严重程度可以通过选择聚酯膜的厚度来调整。根据我们的研究，25.4至102μm的膜厚度用于小鼠的轻度至中度TBI35。我们以前使用过厚度为76.2至127μm的膜在大鼠中产生轻度至中度的TBI19。<ol>
<li>小心地切割聚酯膜，将其插入从动部分和驱动器部分之间，并通过拧紧连接螺栓固定。</li>
		<li>通过使用快速释放接头将气罐连接到减震管。确保膜在驱动器和驱动部分之间紧密固定。</li>
		<li>在冲击管的出口处放置三个压力传感器，相距120°，以监测TBI感应过程中的冲击波特性，如步骤2.2.2和2.2.5中所述。</li>
		<li>使用安装的千分尺确保每个受试者与冲击管设备末端的距离正确。在研究中保持啮齿动物头部的位置（即位置，距离）恒定，以便进行一致的损伤评估。 注意:如1.2.1.所述，通过选择冲击波撞击头部的方向可以引起不同类型的伤害。对于这里描述的诱导轻度至中度TBI的程序，身体垂直于冲击管放置，冲击波撞击头部的侧面。在这种设置下，头部被允许自由移动，因此暴露在冲击波和快速旋转力下，从而产生政变和抵抗效果。</li>
		<li>使用软件的图形用户界面（GUI）从压力传感器启动记录。</li>
	</ol></li>
	<li>在设置中麻醉和定位啮齿动物<ol>
<li>将啮齿动物从储藏室转移出来，用氧气中的4%异氟醚诱导麻醉，并在氧气中保持2%的异氟醚，以减少痛苦和疼痛。 注意:在继续操作之前，请确保动物对脚趾或尾巴的夹击没有反应。确保所有实验动物的麻醉诱导是一致的，包括假对照。该手术需要低水平和短的麻醉时间。</li>
		<li>将完全麻醉的啮齿动物放在带有缓冲垫的PVC管罩中，以保护外围器官免受冲击波的影响。 注意:对照对象被麻醉并放置在设置附近，但不直接受到冲击波的影响。确保控制装置受到减震管产生的噪音的影响。</li>
		<li>将啮齿动物的头部放置在头部放置区域内，并通过直接内置于屏蔽装置中的支撑物或纱布垫从下方支撑它。根据每个啮齿动物的解剖结构确定头部对齐，枕髁与保护性屏蔽的边缘对齐。 注意:避免将压力波直接指向脑干以降低死亡率。已知脑干和颈椎脊髓呼吸中枢的损伤会导致TBI36，37，38啮齿动物模型中的呼吸异常甚至死亡。</li>
	</ol></li>
	<li>啮齿动物暴露于冲击波。<ol>
<li>快速打开压缩气罐的主阀，产生压力峰值，使膜破裂，并产生响亮的爆炸，确认压力波的产生。实验后，膜在取下时会视觉破裂。 注意:高速相机可用于捕获啮齿动物所经历的旋转加速的政变和加速效应，以进行进一步分析。</li>
		<li>听到爆炸后立即关闭气流。</li>
	</ol></li>
	<li>从冲击波暴露中恢复<ol>
<li>在冲击波暴露后，将啮齿动物从设备上取出，并放置在紧邻其侧面的冲击管的平坦表面上。</li>
		<li>监测受试者以确定正确的反射时间（RRT）。使用秒表记录从冲击波暴露到它们恢复固有的矫正反射的时间。（见 图4A）。</li>
		<li>一旦受试者恢复矫正反射，就将他们放在各自的家庭笼子里，在接下来的24小时内监测他们的不良反应（即癫痫发作，呼吸困难，从身体口出血）。</li>
		<li>在初始监测期之后，可以使用研究人员选择的各种生化，神经病理学，神经生理学和行为测定法对受试者进行分析（见下文）。</li>
	</ol></li>
	<li>为下一个实验准备设置和空间。<ol>
<li>用洗涤剂清洁设置以去除异味。</li>
	</ol></li>
</ol>4. 暴露于冲击波/旋转力和控制力的啮齿动物的下游应用
注意:在以前的研究中，使用下游应用（包括生化，神经病理学，神经生理学和行为分析）评估啮齿动物在暴露于冲击波和旋转力后不同时间点的轻度至中度TBI的影响19。
<ol><li>生化分析<ol>
<li>在定义的实验时间点（轻度TBI后数小时至数天），使用所述的标准方案采集组织（例如脑，血液）进行生化分析19。</li>
		<li>使用组织进行生化分析（即免疫印迹，ELISA等）以评估轻度TBI对神经生物学和病理生理过程的影响。</li>
	</ol>
</li>
	<li>神经病理学分析<ol>
<li>在定义的实验时间点（轻度TBI后数小时至数天），用生理盐水溶液经心电泳灌注啮齿动物，然后使用4%多聚甲醛溶液固定组织，如上所述19。 注意:某些应用与多聚甲醛固定不兼容（例如，银染，一些用于免疫组织化学的抗体）。</li>
		<li>使用灌注的固定组织进行解剖学、组织学和分子分析，以评估与轻度 TBI 相关的神经病理学变化，包括所述的神经炎症、神经变性和神经化学变化19。</li>
	</ol>
</li>
	<li>脑切片中的神经生理学分析<ol>
<li>在定义的实验时间点（轻度TBI后数小时至数天），通过斩首牺牲啮齿动物，移除大脑并准备大脑切片，如上所述19。</li>
		<li>执行所述的电生理学记录19 ，以评估轻度TBI对基础突触特性和突触可塑性的影响。</li>
	</ol>
</li>
	<li>行为分析<ol>
<li>在定义的实验时间点（轻度TBI后数小时至数天），评估行为表现，包括运动功能（例如，开放场地，旋转，运动活动;见 图4D）和学习和记忆（例如，恐惧调节，巴恩斯迷宫，莫里斯水迷宫）。</li>
	</ol>
</li>
</ol>

作者声明他们没有竞争利益。

我们在这里提出了一种临床前轻度TBI模型，该模型具有成本效益，易于设置和执行，并允许高通量，可靠和可重复的实验结果。该模型为外周器官提供保护性屏蔽，以便对轻度TBI机制进行重点研究，同时限制全身损伤的混杂变量。相比之下，已知其他爆炸模型会对外围器官造成损害2，39，40。与其他抛丸型号的固定位置相比，?...

仅在美国，创伤性脑损伤（TBI）每年就诊超过200万次。通常由车祸、体育赛事或跌倒引起的轻度 TBI 约占所有 TBI 病例的 80%1。轻度 TBI 被认为是"无声的疾病"，因为患者在初始损伤后的几天和几个月内通常不会出现明显的症状，但在以后的生活中可能会出现严重的 TBI 相关并发症2。此外，爆炸诱发的轻度TBI在服兵中普遍存在，并且与慢性中枢神经系统功能障碍有关3，4，5，6。由于与原始细胞相关的轻度 TBI7，8 发病率上升，与轻度 TBI 相关的神经生物学和病理生理过程的临床前建模因此成为开发 TBI 新型治疗干预措施的重点。
从历史上看，TBI研究主要集中在严重形式的神经创伤上，尽管严重的人类TBI病例数量相对较少。已经开发了用于重度人类TBI的临床前啮齿动物模型，包括受控皮质冲击（CCI）9，10 和液体叩诊损伤（FPI）11 模型，这两种模型都已得到充分验证，可产生可靠的病理生理学效应12，13。这些模型为今天已知的TBI中的神经炎症，神经变性和神经元修复奠定了基础。虽然已经对TBI的病理生理学有了相当多的了解，但目前还没有有效的，FDA批准的治疗TBI的治疗方法。
最近，TBI研究的重点已经扩大到包括更广泛的TBI相关病理学，最终目标是开发有效的治疗干预措施。然而，很少有针对轻度 TBI 的临床前模型被建立出来，显示出可测量的效果，只有少数研究调查了轻度 TBI 谱2，14，15。由于轻度TBI占所有TBI病例的绝大多数，因此迫切需要可靠的轻度TBI模型来促进对人类病因和神经病理生理学的研究，以开发新的治疗策略。
我们与生物医学工程师和航空航天物理学家一起，为轻度至中度TBI建立了可扩展的闭头冲击波模型。这种临床前啮齿动物模型专门用于研究力动力学的影响，包括爆炸波和加速/减速运动，这些影响与在军事战斗，体育赛事，车祸和跌倒中获得的人类轻度TBI有关。由于爆炸波与导致人类轻度TBI的力动力学相关，因此该模型旨在产生具有脉冲的一致弗里德兰德波形，其测量单位为磅/平方英寸（psi）*毫秒（ms）。将脉冲水平缩放至低于小鼠和大鼠定义的肺致死率曲线，以便进行临床前检查16，17，18。此外，该模型允许调查由于动物头部的快速旋转力引起的政变和撞击损伤。这种损伤是几种类型的临床TBI表现所固有的，包括在军事和平民人群中观察到的那些。因此，这种多功能模型符合包含TBI的多种临床表现的需求。
这里介绍的临床前模型产生了与临床轻度TBI相关的可靠且可重复的病理生理学变化，如先前的许多研究所证明的那样17，19，20，21，22，23。使用该模型的研究表明，遭受低强度冲击波的大鼠表现出神经炎症，轴突损伤，微血管损伤，与神经元损伤相关的生化变化以及短期可塑性和突触兴奋性缺陷19。然而，这种轻度TBI模型没有诱发任何宏观神经病理学变化，包括组织损伤，出血，血肿和挫伤19 ，这在使用中度至重度侵袭性TBI模型的研究中很常见10，24。先前的研究19，21，22，23 表明，该临床前模型可用于表征轻度和中度TBI病因的神经生物学和病理生理过程17，19，20，21，22，23。 该模型还允许测试新的治疗化合物和策略，以及确定用于开发有效TBI干预措施的新型，合适的靶标19，21，22，23。
该模型的开发是为了研究爆炸波以及快速旋转力对啮齿动物分子，细胞和行为结果的影响。与此处介绍的冲击波模型类似，已经开发了许多临床前模型，这些模型试图使用气体驱动的超压波来概括轻度至中度TBI2，14，17，25，26，27，28。其他模型的一些局限性包括:动物固定在金属丝网上，头部在撞击时固定;除了大脑之外，外围器官还暴露于波中，这产生了多发性创伤的混杂变量;并且模型很大且静止，这限制了关键参数的变化和调整，以更好地模拟人类TBI的条件。
这种台式气体驱动减震管设置的优点是其相对较低的购置和运行费用成本，以及易于安装和使用。此外，该设置允许在小鼠和大鼠中进行高通量操作并产生受控的可重复冲击波和 体内 结果。为了控制一致的测试条件（即恒定的冲击波和超压），该设置配备了压力传感器。该模型对TBI的优点包括损伤严重程度的可扩展性以及使用非侵入性闭合头手术诱导轻度TBI。峰值超压和随后的脑损伤随着聚酯膜的增厚以一致的可扩展方式增加17。通过膜厚度调整TBI严重程度的能力是确定特定结局指标（例如，神经炎症）变得明显的水平的有用工具。为外周器官提供保护性屏蔽，还可以通过避免或减少全身损伤（如肺或胸损伤）的混杂变量，重点检查轻度TBI机制。此外，这种设置允许选择方向，通过该方向，爆炸波撞击/穿透头部（即正面，侧面，顶部或下方），因此可以调查不同类型的TBI诱导侮辱。这里描述的诱导轻度至中度TBI的标准程序采用侧面暴露来评估冲击波损伤与快速旋转力引起的政变和痉挛损伤的影响。此外，为了专门研究爆炸引起的伤害，可以在该模型中采用自上而下的冲击波暴露。

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</table>

low-intensity blast wave model for preclinical assessment of closed-head mild traumatic brain injury in rodents

创伤性脑损伤（TBI）是一个大规模的公共卫生问题。轻度TBI是最常见的神经创伤形式，在美国占了大量的医疗就诊。目前没有FDA批准的治疗TBI的治疗方法。与军事相关的爆炸诱发的TBI的发病率增加，进一步突出了对有效TBI治疗的迫切需要。因此，新的临床前TBI动物模型概括了人类爆炸相关TBI的各个方面，将大大推进对轻度至中度TBI的神经生物学和病理生理过程的研究工作，以及开发TBI的新型治疗策略。
在这里，我们提出了一个可靠的，可重复的模型，用于研究轻度至中度原始细胞诱导的TBI的分子，细胞和行为影响。我们描述了一种分步方案，用于啮齿动物中闭合头部，爆炸引起的轻度TBI，使用由配备压电压力传感器的气体驱动减震管组成的台式设置，以确保一致的测试条件。我们建立的设置的好处是其相对低成本，易于安装，易于使用和高吞吐量容量。这种非侵入性TBI模型的其他优点包括爆炸峰超压的可扩展性和可控可重复结果的产生。该TBI模型的可重复性和相关性已在许多下游应用中进行了评估，包括神经生物学，神经病理学，神经生理学和行为分析，支持使用该模型来表征轻度至中度TBI病因背后的过程。

使用三种不同的膜厚度（25.4，50.8和76.2μm）测试了冲击波设置的可扩展性。使用压电压力传感器评估头部放置区域和冲击管设备出口处的峰值压力水平（见 图1 和 图2）。峰值压力与两个传感器位置的膜厚度一致（图3A，B），表明峰值压力本质上是可扩展的。可以利用安装程序的此属性来校准系统并评估其可伸缩性，...

Watch this Scientific Journal Video about Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents at JoVE.com

Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents

我们在这里提出了啮齿动物冲击波模型的方案，以研究轻度至中度创伤性脑损伤的神经生物学和病理生理学影响。我们建立了一个气体驱动的台式设置，配备了压力传感器，允许可靠和可重复地产生爆炸引起的轻度至中度创伤性脑损伤。

低强度冲击波模型用于啮齿动物闭头轻度创伤性脑损伤的临床前评估

Traumatic brain injury (TBI) is a large-scale public health problem. Mild TBI is the most prevalent form of neurotrauma and accounts for a large number of ...

low-intensity-blast-wave-model-for-preclinical-assessment-closed-head

Research

JoVE Journal

Neuroscience

2.6K 次观看.  Veterans Affairs. 我们在这里提出了啮齿动物冲击波模型的方案，以研究轻度至中度创伤性脑损伤的神经生物学和病理生理学影响。我们建立了一个气体驱动的台式设置，配备了压力传感器，允许可靠和可重复地产生爆炸引起的轻度至中度创伤性脑损伤。

视频: Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological impairments 1. Two pervasive and disabling symptoms experienced by TBI survivors, memory deficits and a reduction in seizure threshold, are thought to be mediated by TBI-induced hippocampal dysfunction 2,3. In order to demonstrate how altered hippocampal circuit function adversely affects behavior after TBI in mice, we employ lateral fluid percussion injury, a commonly used animal model of TBI that recreates many features of human TBI including neuronal cell loss, gliosis, and ionic perturbation 4-6.
	Here we demonstrate a combinatorial method for investigating TBI-induced hippocampal dysfunction. Our approach incorporates multiple ex vivo physiological techniques together with animal behavior and biochemical analysis, in order to analyze post-TBI changes in the hippocampus. We begin with the experimental injury paradigm along with behavioral analysis to assess cognitive disability following TBI. Next, we feature three distinct ex vivo recording techniques: extracellular field potential recording, visualized whole-cell patch-clamping, and voltage sensitive dye recording. Finally, we demonstrate a method for regionally dissecting subregions of the hippocampus that can be useful for detailed analysis of neurochemical and metabolic alterations post-TBI.
	These methods have been used to examine the alterations in hippocampal circuitry following TBI and to probe the opposing changes in network circuit function that occur in the dentate gyrus and CA1 subregions of the hippocampus (see Figure 1). The ability to analyze the post-TBI changes in each subregion is essential to understanding the underlying mechanisms contributing to TBI-induced behavioral and cognitive deficits. 
	The multi-faceted system outlined here allows investigators to push past characterization of phenomenology induced by a disease state (in this case TBI) and determine the mechanisms responsible for the observed pathology associated with TBI.

A multi-faceted approach to investigating functional changes to hippocampal circuitry is explained. Electrophysiological techniques are described along with the injury protocol, behavioral testing and regional dissection method. The combination of these techniques can be applied in similar fashion for other brain regions and scientific questions.

调查轻度创伤性脑损伤海马电路功能的改变

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological ...

科研

神经科学

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies using Drosophila have contributed important breakthroughs in understanding neurological processes. Thus, with the goal of understanding the cellular and molecular basis of TBI pathologies in humans, we developed the High Impact Trauma (HIT) device to inflict closed head TBI in flies. Flies subjected to the HIT device display phenotypes consistent with human TBI such as temporary incapacitation and progressive neurodegeneration. The HIT device uses a spring-based mechanism to propel flies against the wall of a vial, causing mechanical damage to the fly brain. The device is inexpensive and easy to construct, its operation is simple and rapid, and it produces reproducible results. Consequently, the HIT device can be combined with existing experimental tools and techniques for flies to address fundamental questions about TBI that can lead to the development of diagnostics and treatments for TBI. In particular, the HIT device can be used to perform large-scale genetic screens to understand the genetic basis of TBI pathologies.

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Here we describe a method to inflict closed head traumatic brain injury (TBI) in Drosophila. This method provides a gateway to investigate the cellular and molecular mechanisms that underlie TBI pathologies using the vast array of experimental tools and techniques available for flies.

方法对敌人造成闭合性颅脑创伤性脑损伤<em&gt;果蝇</em

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies ...

A Novel In Vitro Model of Blast Traumatic Brain Injury

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the detonation of explosive devices, however, the mechanisms that underlie the brain damage resulting from blast overpressure exposure are not entirely understood and are believed to be unique to this type of brain injury. Preclinical models are crucial tools that contribute to better understand blast-induced brain injury. A novel in vitro blast TBI model was developed using an open-ended shock tube to simulate real-life open-field blast waves modelled by the Friedlander waveform. C57BL/6N mouse organotypic hippocampal slice cultures were exposed to single shock waves and the development of injury was characterized up to 72 h using propidium iodide, a well-established fluorescent marker of cell damage that only penetrates cells with compromised cellular membranes. Propidium iodide fluorescence was significantly higher in the slices exposed to a blast wave when compared with sham slices throughout the duration of the protocol. The brain tissue injury is very reproducible and proportional to the peak overpressure of the shock wave applied.

A Novel In Vitro Model of Blast Traumatic Brain Injury

This paper describes a novel model of primary blast traumatic brain injury. A compressed-air driven shock tube is used to expose in vitro mouse hippocampal slice cultures to a single shock wave. This is a simple and rapid protocol generating a reproducible brain tissue injury with a high throughput.

一种新的脑外伤体损伤模型

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the ...

Effects of Blast-induced Neurotrauma on Pressurized Rodent Middle Cerebral Arteries

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral vascular effects. Impact (i.e., non-blast) traumatic brain injury (TBI) is known to decrease pressure autoregulation in the cerebral vasculature in both humans and experimental animals. The hypothesis that blast-induced traumatic brain injury (bTBI), like impact TBI, results in impaired cerebral vascular reactivity was tested by measuring myogenic dilatory responses to reduced intravascular pressure in rodent middle cerebral arterial (MCA) segments from rats subjected to mild bTBI using an Advanced Blast Simulator (ABS) shock tube. Adult, male Sprague-Dawley rats were anesthetized, intubated, ventilated and prepared for Sham bTBI (identical manipulation and anesthesia except for blast injury) or mild bTBI. Rats were randomly assigned to receive Sham bTBI or mild bTBI followed by sacrifice 30 or 60 min post-injury. Immediately after bTBI, righting reflex (RR) suppression times were assessed, euthanasia at the time points post-injury was completed, the brain was harvested and the individual MCA segments were collected, mounted and pressurized. As the intraluminal pressure perfused through the arterial segments was reduced in 20 mmHg increments from 100 to 20 mmHg, MCA diameters were measured and recorded. With decreasing intraluminal pressure, MCA diameters steadily increased significantly above baseline in the Sham bTBI groups while MCA dilator responses were significantly reduced (p &#60; 0.05) in both bTBI groups as evidenced by the impaired, smaller MCA diameters recorded for the bTBI groups. In addition, RR suppression in the bTBI groups was significantly (p &#60; 0.05) higher than in the Sham bTBI groups. MCA&#39;s collected from the Sham bTBI groups exhibited typical vasodilatory properties to decreases in intraluminal pressure while MCA&#39;s collected following bTBI exhibited significantly impaired myogenic vasodilatory responses to reduced pressure that persisted for at least 60 min after bTBI.

Here, we present a protocol to describe methods for ex vivo vascular reactivity determination following a primary blast traumatic brain injury (bTBI) using isolated, pressurized, rodent middle cerebral arterial (MCA) segments. bTBI induction is accomplished using a shock tube, also known as an Advanced Blast Simulator (ABS) device.

爆炸性神经损伤对压生啮鼠中脑动脉的影响

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral ...

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous variability and heterogeneity (age, gender, type of trauma, other possible pathologies, etc.), animal models play a key role in unraveling factors that are limitations in clinical research. They provide a standardized and controlled setting to investigate the biological mechanisms of injury and repair following TBI. However, not all animal models mimic the diffuse and subtle nature of mTBI effectively. For example, the commonly used controlled cortical impact (CCI) and lateral fluid percussion injury (LFPI) models make use of a craniotomy to expose the brain and induce widespread focal trauma, which are not commonly seen in mTBI. Therefore, these experimental models are not valid to mimic mTBI. Thus, an appropriate model should be used to investigate mTBI. The Marmarou weight drop model for rats induces similar microstructural alterations and cognitive impairments as seen in patients who sustain mild trauma; therefore, this model was selected for this protocol. Conventional computed tomography and magnetic resonance imaging (MRI) scans commonly show no damage following a mild injury, because mTBI induces often only subtle and diffuse injuries. With diffusion weighted MRI, it is possible to investigate microstructural properties of brain tissue, which can provide more insight into the microscopic alterations following mild trauma. Therefore, the goal of this study is to obtain quantitative information of a selected region-of-interest (i.e., hippocampus) to follow up disease progression after obtaining a mild and diffuse brain injury.

The overall goal of this procedure is to obtain quantitative microstructural information of the hippocampus in a rat with mild traumatic brain injury. This is done using an advanced diffusion-weighted magnetic resonance imaging protocol and region-of-interest based analysis of parametric diffusion maps.

轻度创伤性脑损伤大鼠海马学的高级扩散成像

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and understanding the mechanisms of how a TBI alters brain function. The availability of multiple animal models of TBI is necessary to model the different aspects and severities of TBI seen in people. This manuscript describes the use of a midline closed head injury (CHI) to develop a mouse model of mild TBI. The model is considered mild because it does not produce structural brain lesions based on neuroimaging or gross neuronal loss. However, a single impact creates enough pathology that cognitive impairment is measurable at least 1 month after injury. A step-by-step protocol to induce a CHI in mice using a stereotaxically guided electromagnetic impactor is defined in the paper. The benefits of the mild midline CHI model include the reproducibility of the injury-induced changes with low mortality. The model has been temporally characterized up to 1 year after the injury for neuroimaging, neurochemical, neuropathological, and behavioral changes. The model is complementary to open skull models of controlled cortical impact using the same impactor device. Thus, labs can model both mild diffuse TBI and focal moderate-to-severe TBI with the same impactor.

The protocol describes mild traumatic brain injury in a mouse model. In particular, a step-by-step protocol to induce a mild midline closed head injury and the characterization of the animal model is fully explained.

小鼠轻度创伤性脑损伤的电磁控制闭头模型

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and ...

Assessing Changes in Synaptic Plasticity Using an Awake Closed-Head Injury Model of Mild Traumatic Brain Injury

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of closed-head mTBI in the preclinical setting to increase translatability to the clinical population. The awake closed-headed injury (ACHI) model uses a modified controlled cortical impactor to deliver closed-headed injury, inducing clinically relevant behavioral deficits without the need for a craniotomy or the use of an anesthetic.
This technique does not normally induce fatalities, skull fractures, or brain bleeds, and is more consistent with being a mild injury. Indeed, the mild nature of the ACHI procedure makes it ideal for studies investigating repetitive mTBI (r-mTBI). Growing evidence indicates that r-mTBI can result in a cumulative injury that produces behavioral symptoms, neuropathological changes, and neurodegeneration. r-mTBI is common in youths playing sports, and these injuries occur during a period of robust synaptic reorganization and myelination, making the younger population particularly vulnerable to the long-term influences of r-mTBI.
Further, r-mTBI occurs in cases of intimate partner violence, a condition for which there are few objective screening measures. In these experiments, synaptic function was assessed in the hippocampus in juvenile rats that had experienced r-mTBI using the ACHI model. Following the injuries, a tissue slicer was utilized to make hippocampal slices to evaluate bidirectional synaptic plasticity in the hippocampus at either 1 or 7 days following the r-mTBI. Overall, the ACHI model provides researchers with an ecologically valid model to study changes in synaptic plasticity following mTBI and r-mTBI.

Here, it is demonstrated how an awake closed-head injury model can be used for examining the effects of repeated mild traumatic brain injury (r-mTBI) on synaptic plasticity in the hippocampus. The model replicates important features of r-mTBI in patients and is used in conjunction with in vitro electrophysiology.

使用轻度创伤性脑损伤的清醒闭合性头部损伤模型评估突触可塑性的变化

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of ...

在 mTBI 大鼠模型中验证损伤反应和行为评估

Rat Model of Closed-Head Mild Traumatic Injury and its Validation

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful insights, developing a stable and reproducible animal model is essential. In this study, we report a detailed description of a closed-head mTBI model and a representative validation method using Sprague-Dawley rats to verify the modeling effect. The model involves dropping a 550 g mass weight from a height of 100 cm directly onto the head of a rat on a destructible surface, followed by a 180-degree turn. To assess the injury, rats underwent a series of neurobehavioral assessments 10 min post-injury, including time of loss of consciousness, first seeking-behavior time, escape ability, and beam balance ability test. During the acute and subacute stages following the injury, behavioral tests were conducted to assess motor coordination ability (Beam task), anxiety (Open Field test), and learning and memory abilities (Morris Water Maze test). The closed-head mTBI model produced a consistent injury response with minimal mortality and replicated real-life situations. The validation method effectively verified the model development and ensured the stability and consistency of the model.

作者聚焦:推进创伤性脑损伤研究 - 用于准确复制和快速评估的闭头模型 

Here, we present a closed-head mild traumatic brain injury (mTBI) rat model and its validation exhibiting remarkable similarity to human mTBI concerning behavioral manifestations during the acute and subacute stages.

闭合头轻度创伤大鼠模型及其验证

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful ...