Neuroprotection of the retina through application of carbon monoxide releasing molecules (CO-RM) after retinal ischemia and reperfusion injury.

术后认知功能障碍和神经系统显著性的一个根本原因最常被认为是脑缺血和再灌注（I/R）损伤，发生在麻醉期间或由于所有年龄段患者的手术干预。我们选择眼作为一个神经器官，其功能部分与大脑相当，以分析和抵消I/R相关的神经元损伤。由于诸如视网膜中央动脉阻塞或糖尿病性视网膜病变的疾病引起的眼部I/R损伤最终导致视网膜的神经元破坏，最经常导致视力损害。由于其高度特化，视网膜中的神经元细胞对眼内稳态的失衡反应最敏感。到目前为止，这些高度特化的神经元细胞的任何形式的再生似乎几乎是不可能的。我们的实验室最近表明，吸入一氧化碳（CO）预处理在视网膜I/R模型中发挥保护作用。I/R损伤后7天，与接受室内空气的对照组相比，CO预处理组的视网膜神经节细胞（RGC）死亡减少了52%。在I/R损伤后0- 3 h吸入CO同样减轻RGC损失。在初步的实验中，我们已经表明，炎症反应的抑制CO结合半胱天冬酶-3活性的衰减。相比之下，I/R损伤前/后不存在CO导致炎性蛋白的显著更高表达以及视网膜胶质细胞的巨大活化和增殖。尽管有这种描述，这些影响的分子病因仍然知之甚少。据推测，负责的途径包括可溶性鸟苷酸环化酶（sGC）和丝裂原活化蛋白激酶（MAPK）的激活。除了吸入性应用的一氧化碳（CO）由于其潜在的毒副作用而使其临床应用受到限制外，一氧化碳释放分子（CO-RM）似乎也具有细胞保护作用，因此越来越受到人们的关注，而且新的CO-RM --如ALF-186 --是水溶性的，并且在体内显示出长期有效性。视网膜I/R损伤后局部（玻璃体内）和全身给予CO-RM ALF 186的优点及其对视网膜神经元的神经保护特性迄今尚未研究。基于这些事实，我们将研究以下假设：假设1：ALF 186的全身应用导致视网膜I/R后处理大鼠模型中神经元细胞死亡和炎症的减少。假设2：ALF 186的保护特性由MAPK、sGC及其抑制视网膜神经炎症的潜力介导。假设三：局部应用ALF 186（玻璃体内）能够减少后调节视网膜I/R大鼠模型中的神经元细胞死亡和视网膜炎症。

One fundamental reason of postoperative cognitive dysfunction and neurological conspicuousness is most often presumed to cerebral ischemia- and reperfusion (I/R) injuries, occurring during anesthesia or due to surgical interventions in patients of all ages. We chose the eye as a neuronal organ, which in function is partly comparable to the brain, to analyze and counteract I/R related neuronal damage. Ocular I/R injuries due to diseases such as central retinal artery occlusion or diabetic retinopathy ultimately result in neuronal destruction of the retina, most often leading to visual impairment. Because of their high specialization neuronal cells in the retina react most sensitive regarding dysbalance of ocular homeostasis. Any form of regeneration of these highly specialized neuronal cells seemed almost impossible, so far. Our lab has recently shown that preconditioning with inhalative carbon monoxide (CO) exerts protective effects in a retinal I/R model. Seven days after I/R injury, retinal ganglion cell (RGC) death decreased by 52% in the CO-preconditioning group compared with controls receiving room air. CO inhalation after 0-3h after I/R injury likewise attenuated RGC loss. In preliminary experiments, we have shown that the inflammatory response is inhibited by CO combined with an attenuation of caspase-3 activity. By contrast, the absence of CO before/after I/R injury led to significantly higher expression of inflammatory proteins and to a tremendous activation and proliferation of retinal glia cells. Despite this description, the molecular etiologies of these effects remain poorly understood. It is assumed that responsible pathways include the activation of the soluble guanylyl cyclase (sGC) and the mitogen activated protein kinases (MAPK). Apart from the inhalative application of CO, which still triggers reservations about its clinical application due to its potential toxic side effects, carbon monoxide releasing molecules (CO-RM) seem to exert cytoprotective effects as well, thus gaining increasingly attention.Furthermore, new CO-RM - like ALF-186 - are now water-soluble and show longstanding effectiveness in vivo. The advantages of topic (intravitreally) and systemic administration of the CO-RM ALF186 after retinal I/R injury and its neuroprotective properties on retinal neurons have not been investigated so far.Based on these facts, we will investigate the following hypotheses:Hypothesis 1: The systemic application of ALF186 leads to a reduction in neuronal cell death and inflammation in a postconditioning retinal I/R rat model. Hypothesis 2: The protective properties of ALF186 are mediated by the MAPK, the sGC and by its potential to suppress neuroinflammation in the retina. Hypothesis 3: Topical application of ALF186 (intravitreally) is able to reduce neuronal cell death and retinal inflammation in a postconditioning retinal I/R rat model.