The Role of Adenosine in Retinal Ischemia

描述（由申请人提供）：此竞争性修订申请为原始资助申请RO1EY10343提出的新目标寻求额外资金。最初的申请是为了进一步研究大鼠视网膜体内缺血预处理（IPC）的机制而寻求资金。IPC是一个短暂的缺血期，能够诱导对损伤性缺血的强耐受性。因此，IPC提供了神经保护，对其机制的研究有望导致临床可翻译的预防缺血性损伤的方法。视网膜动脉或静脉闭塞、青光眼、动脉粥样硬化或全身性疾病（如糖尿病）的视网膜缺血可能导致严重的视力丧失。由于这些疾病的治疗仍不令人满意，激活内源性神经保护机制的前景令人兴奋，对预防这些导致严重残疾的疾病具有重要意义。我们最近还观察到，在损伤性缺血后进行短暂的缺血刺激可以诱导更强的神经保护，这与预处理中使用的方案相反。这种效应被称为后条件作用。本提案中提出的初步数据支持后适应（Post-C）的保护作用，但也表明其机制虽然相关，但可能与IPC不同。研究后c的机制有可能对视网膜内源性神经保护产生新的见解。此外，与IPC不同，Post-C本身可以在缺血发作后直接应用于临床。因此，我们提出了一个竞争性修订，将我们的研究扩展到一个新的特定目标，即研究Post-C的机制。我们假设后c通过激活MAP激酶改变了缺血后再灌注时视网膜细胞的分子环境。这个竞争性修订的研究设计建立在当前资助的拨款中使用的基础上，增加了对MAP激酶的详细研究。我们将使用当前开发的创新方法，即使用干扰RNA在体内产生MAP激酶亚型的靶向，特异性敲低。结合先进的视网膜功能电生理评估、组织学检查以及细胞死亡和分子机制的表征，我们将使用一个强大而稳健的模型来阐明一种有希望诱导视网膜内源性神经保护的方法的机制。

DESCRIPTION (provided by applicant): This competitive revision application seeks additional funding for new aims that are being proposed for original grant application RO1EY10343. The original application sought funds to further our studies of the mechanisms of ischemic preconditioning (IPC) in the rat retina in vivo. IPC is a brief period of ischemia that is capable of inducing robust tolerance to the effects of damaging ischemia. Thus, IPC provides neuroprotection, and the study of its mechanisms is expected to lead to clinically translatable means to prevent ischemic injury. Significant visual loss may result from retinal ischemia in retinal arterial or venous occlusion, glaucoma, atherosclerosis, or in systemic disorders such as diabetes mellitus. Because treatment of these disorders remains unsatisfactory, the prospect of activating endogenous neuroprotective mechanisms is exciting and of significance to preventing these disorders that result in significant disability. We also recently observed that an even more robust neuroprotection could be induced by placing the brief ischemic stimulus AFTER the damaging ischemia, which is the reverse of the protocol used in preconditioning. This effect is known as post- conditioning. Preliminary data presented in this proposal support the protective effect of post-conditioning (Post-C), but also suggest that the mechanisms, while related, may not be the same as IPC. Examining mechanisms of Post-C has the potential to yield new insights into endogenous neuroprotection in the retina. Moreover, Post-C, unlike IPC, may itself be directly applied clinically, after an episode of ischemia. Accordingly, we propose a competitive revision that will expand our studies into a new specific aim, i.e., to examine the mechanisms of Post-C. We hypothesize that Post-C alters the molecular environment of retinal cells during reperfusion following ischemia, via activation of MAP kinases. The research design in this competitive revision builds upon that used in the currently funded grant, adding detailed study of the MAP kinases. We will use innovative methodology developed during the current period, i.e., the use of interfering RNA to procude a targeted, specific knock down in vivo of MAP kinase subtypes. Combining state of art retinal functional electrophysiological assessment, histological examination, and characterization of cell death and molecular mechanisms by both well established and newer technologies, we will use a powerful and robust model to elucidate the mechanisms of a promising means to induce endogenous neuroprotection in the retina. PUBLIC HEALTH RELEVANCE: Combining state of art retinal functional electrophysiological assessment, histological examination, and characterization of cell death and molecular mechanisms by both well established and newer technologies, we will use a powerful and robust model to elucidate the mechanisms of a promising means to induce endogenous neuroprotection in the retina.