Postconditioning promotes recovery in the neurovascular unit after stroke

项目摘要/摘要 缺血后处理的定义是一系列短暂的缺血-再灌注的保护性发作。 在长时间的脑缺血侮辱之后。到目前为止，大多数实验研究都集中在 缺血后处理的急性机制，主要在24小时内。然而，它的作用和机制 卒中后大脑中较长时间的后处理仍有待充分阐明。我们的假设是 缺血后处理促进卒中后神经血管单位的恢复，部分是通过增加 在星形胶质细胞中产生BDNF和MMP9，从而促进神经发生和血管生成。这些因素 可能允许后处理放大神经发生和血管生成，从而改善中风的恢复。 我们的初步数据显示，后处理在3天和2周时具有神经保护作用，增加 神经发生和血管生成并上调Akt、MMP9和BDNF蛋白表达水平，尤其是 梗死灶周围皮质内的反应性星形胶质细胞。我们将在这些试点数据的基础上，追求两个目标。 目的1：研究条件化后对体外培养的星形胶质细胞保护神经元能力的影响。 我们将使用原代细胞培养和培养液转移实验来检验后处理的假设 增强星形胶质细胞产生BDNF和MMP9的能力，从而保护神经元并促进 他们在缺氧缺糖后的神经再生能力恢复。 目的2：探讨条件化后对星形胶质细胞分泌BDNF和MMP9的影响。 中风的活体康复。我们将使用大鼠局灶性脑缺血模型在体内验证这一假设 后处理增加卒中恢复期星形胶质细胞产生BDNF和MMP9。我们将评估 通过阻断MMP9和/或BDNF并跟踪随后对神经恢复的影响来确定因果关系。为了测试 后处理通过星形胶质细胞源性脑源性神经营养因子促进神经发生和血管生成的假说 和MMP9，我们将抑制星形细胞产生BDNF和MMP9，然后记录后续的 对神经发生、血管生成的影响，并随着时间的推移与神经学结果相关。我们还将使用 星形胶质细胞特异性脑源性神经营养因子缺陷小鼠来证实我们的假设，正如之前的评论者所建议的那样。我们 除了在KO小鼠中，缺血后处理的神经保护作用被部分阻止。 了解长期卒中康复的后处理机制是非常必要的。 此R03允许新的PI开始这条调查路线，以进一步促进开发和 翻译后处理作为中风的一种治疗方法。

Project Summary/Abstract Ischemic postconditioning is defined as a protective series of brief episodes of ischemia-reperfusion subsequent to a prolonged ischemic insult. Thus far, the majority of experimental studies have focused on the acute mechanisms of ischemic postconditioning, mostly at 24 hours. However, effects and mechanisms of postconditioning in the brain for longer periods post-stroke remain to be fully elucidated. Our hypothesis states that ischemic postconditioning promotes neurovascular unit recovery after stroke, in part by augmenting the production of BDNF and MMP9 in astrocytes, thus promoting neurogenesis and angiogenesis. These factors may allow postconditioning to amplify neurogenesis and angiogenesis, hence improving stroke recovery. Our preliminary data showed that postconditioning is neuroprotective at 3 days and 2 weeks, increases neurogenesis and angiogenesis and elevates Akt, MMP9 and BDNF protein expression levels especially in reactive astrocytes within the peri-infarct cortex. We will build on these pilot data by pursuing 2 aims. Aim 1: Investigate effects of postconditoning on the ability of astrocytes to protect neurons in vitro. We will use primary cell cultures and media transfer experiments to test the hypothesis that postconditioning amplifies the ability of astrocytes to produce BDNF and MMP9, which then protects neurons and promotes their neuroplastic recovery after oxygen-glucose deprivation. Aim 2: Investigate the effects of postconditoning on astrocytic production of BDNF and MMP9 during stroke recovery in vivo. We will use rat models of focal cerebral ischemia to verify in vivo, the hypothesis that postconditioning increases astrocytic production of BDNF and MMP9 during stroke recovery. We will assess causality by blocking MMP9 and/or BDNF and tracking the subsequent effects on neurologic recovery. To test the hypothesis that postconditioning augments neurogenesis and angiogenesis via astrocyte-derived BDNF and MMP9, we will suppress astrocytic production of BDNF and MMP9, and then document the subsequent effects on neurogenesis, angiogenesis and correlate this with neurologic outcomes over time. We will also use astrocyte specific BDNF deficient mice to confirm our hypothesis, as suggested by previous reviewers. We expect that in KO mice the neuroprotective effect of ischemic postconditioning is in part prevented. Understanding the mechanisms of postconditioning in long-term stroke recovery is fundamentally required. This R03 allows a new PI to begin this line of investigation to further contribute to the development and translation of postconditioning as a therapeutic approach for stroke.