An organotypic model of traumatic brain injury

在过去的十年里，人们已经见证了大量的科学活动，以研究创伤性脑损伤的分子机制，这是由压倒性的证据驱动的，即通过药物抑制细胞凋亡的神经保护有可能显着降低脑创伤的影响。系统研究神经保护剂的关键条件是 一种准确表征的临床相关体外脑损伤模型。尽管有这种明显的需求，但将这种确定的、现实的创伤传递到体外标记中的标本的能力远远落后于用于测量反应的分子和生化测定的复杂性。在神经生物学家和生物工程师的共同努力下，我们开发了 一种使器官型脑培养物经受角加速度诱导的剪切损伤的体外脑损伤模型。在该模型中，器官型脑培养物真实地模拟了三维细胞基质中的体内表观异质细胞群，而角加速度诱导的剪切应变提供了一个可扩展的、定义的和临床上可接受的模型。 相关机械损伤。 我们假设我们的器官型脑培养物的加速度模型可以真实地再现创伤性脑损伤，其中所传递的剪切应变幅度可以在细胞水平上量化。运用我们的模型，我们将能够确定细胞类型特异性损伤的脆弱性，并确定caspase-8和caspase-9是否影响脑创伤后的细胞死亡。 我们建议完成我们的新型脑损伤系统的正式实验表征，包括评估所提供的角加速度大小和确定器官型标本的组成特性（目的1）。所得到的实验源数据将直接适用于制定一个现实的分析模型，该模型允许在主要机械损伤期间的任何时间点对整个脑标本的剪切损伤进行计算模拟（目标2）。基于并伴随着这种严格的系统表征，我们将运用脑损伤模型来建立剂量/反应历史（目标3），我们将描述继发于机械损伤的缺氧性脑损伤的影响（目标4）。最后，我们将使用我们的arganotypic创伤模型来确定caspase-8和caspase-9的神经保护潜力（目的5）。 成功完成后，这种综合研究方法的结果将产生一个良好的特征，可扩展，可重复和临床相关的脑损伤模型。考虑到目前正在开发的旨在抑制主要机械性脑损伤的继发性效应级联的治疗性干预的巨大兴趣，我们的器官型创伤模型将直接解决对良好表征的实验性脑损伤的快速增长的需求。 系统提供一个临床相关的创伤性损伤-并可能证明是至关重要的发现半胱天冬酶为基础的神经保护机制。

The past decade has witnessed intense scientific activity to investigate molecular mechanisms of traumatic brain injury, driven by overwhelming evidence that neuropotection by pharmacological inhibition of apoptosis has the potential to dramatically reduce the effects of brain trauma. Key requisite for the systematic investigation of neuroprotective agents is an accurately characterized, clinically relevant in vitro brain injury model. Despite this obvious need, the ability to deliver such defined, realistic trauma to specimens in vitrolags far behind the sophistication of molecular and biochemical assays used to measure the response. In a collaborative effort between neurobiologists and bioengineers, we therefore developed an in vitrobrain injury model which subjects organotypic brain cultures to angular acceleration-induced shear injury. In this model, organotypic brain cultures realistically model the in vivoapparent heterogeneous cell population in a three-dimensional cellular matrix, while angular acceleration-induced shear strain delivers a scalable, defined, and clinically relevant mechanical insult. We hypothesize that our acceleration model of organotypic brain cultures can realistically reproduce traumatic brain injury, where the delivered shear strain magnitude can be quantified on a cellular level. Exercising our model, we will be able to determine cell type specific injury vulnerability, and to determine if caspase-8 and caspase-9 affect cell death following brain trauma. We propose to complete a formal experimental characterization of our novel brain injury system, including assessment of the delivered angular acceleration magnitude and determination of the constitutive properties of the organotypic specimen (Aim 1). The resulting experimental source data will be directly applicable to formulate a realistic analytical model that allows computational simulation of the shear injury throughout the brain specimen for any point in time during the primary mechanical insult (Aim 2). Based on and concomitant to this rigorous system characterization, we will exercise the brain injury model to establish a dose/response history (Aim 3), and we will delineate the effects of hypoxic brain injury (Aim 4), secondary to the mechanical insult. Finally, we will employ our arganotypic trauma model to determine the neuroprotective potential of caspase-8 and caspase-9 (Aim 5). Upon successful completion, the results of this integrative research approach will yield a well-characterized, scalable, reproducible and clinically relevant brain injury model. Considering the vast interest in therapeutic interventions now under development aimed at inhibiting the cascade of secondary effects of primarily mechanical brain injuries, our organotypic trauma model will directly address the rapidly increasing demand for a well characterized, experimental system to deliver a clinically relevant traumatic insult - and may prove crucial for the discovery of caspase-based neuroprotective mechanisms.