Direct visualization of longitudinal effects of drug therapy on white matter in diffuse injured brain

描述(由申请人提供)：该项目将提供高含量的数据，将用于基础和临床前研究。基础研究方面：我们将使用一种高分辨率、皮质下、活体成像的新方法来填补在细胞水平上弥漫性创伤性脑损伤在活体小鼠皮质下白质中动态变化的关键知识空白，损伤后60天。这些知识将使我们对脑外伤后发生的进行性退行性变有新的认识，并为未来的联合药物治疗优化治疗窗口。我们将使用位于皮质下白质束上的永久植入的微透镜在活体小鼠身上获得这些图像，并使用多光子显微镜通过该透镜定期成像。我们将揭示以前未曾见过的轴突变性、小胶质细胞渗透和激活的时空动力学，以及该区域细胞分辨率的微血管变化。临床前方面：我们还将使用我们观察到的三个关键结果来评估一种目前处于临床前试验中的药物的疗效。这种名为米诺环素的药物是FDA批准的抗生素，在小鼠实验性创伤性脑损伤几小时内单次给药时，可以减少轴突损失和小胶质细胞的激活。我们假设，损伤后3天给予的剂量将具有显著的(1)减少轴突丢失和(2)减少小胶质细胞激活的相同的治疗益处。我们进一步假设米诺环素将导致微循环速率的显著改善。扩大这种有希望的药物的治疗窗口将更好地将其转化为临床。

DESCRIPTION (provided by applicant): This project will provide high-content data that will be used for both basic and preclinical research. BASIC RESEARCH ASPECT: We will use a novel method of high-resolution, subcortical, in vivo imaging to fill critical gaps in knowledge about th dynamics of diffuse traumatic brain injury at a cellular level in subcortical white matter in live mice over a 60-day period post-injury. This knowledge will give us new insights into understanding the progressive degeneration that happens after TBI and for optimizing therapeutic windows for future combination drug therapy. We will obtain these images in live mice using a permanently implanted microlens positioned over a subcortical white matter tract and periodically image through this lens using a multiphoton microscope. We will reveal previously unseen spatio-temporal dynamics of axon degeneration, microglia infiltration and activation, and microvascular changes with cellular resolution in this region. PRECLINICAL ASPECT: We will also use 3 key outcomes from our observations to evaluate the efficacy of a drug which is now in preclinical trials. This drug, minocycline, is an FDA-approved antibiotic that has reduced axonal loss and microglial activation when given in a single dose within a few hours of experimental traumatic brain injury in mice. We hypothesize that a dose given 3 days post-injury will have the same therapeutic benefits of significantly (1) reducing axonal loss and (2) reducing microglial activation. We further hypothesize that minocycline will result in significant improvement in microcirculation rates. Widening the therapeutic window for this promising drug will better position it for translation to the clinic.