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MECHANISMS OF RETINAL PHOTOTOXICITY

视网膜光毒性的机制

基本信息

批准号：
3261588
负责人：
ROBERT J STEPHENS
金额：
$ 27.08万
依托单位：
SRI INTERNATIONAL
依托单位国家：
美国
项目类别：
财政年份：
1985
资助国家：
美国
起止时间：
1985-07-01 至 1993-10-31
项目状态：
已结题

项目摘要

Long-term objective: to identify--and eventually control--the cytotoxic molecule(s) formed on irradiation of the retina with visible light, causing photosensitive cells to degenerate. The theoretical mechanism being tested is based on the concept of lipid peroxidation and the formation of intermediates that are toxic to the photoreceptor cells and, under certain conditions, to the retinal pigment epithelium (RPE). Specific aims: to 1) quantitate hydroperoxides and aldehydes of linoleic and docosahexaenoic acids that have been identified in the retina and photoreceptor cells and extend this research to products from other significant PUFAs found in photosensitive cells; 2) synthesize mass-labeled molecules as standards for quantifying peroxidation products by GC-MS; 3) quantitate PUFA change resulting from photic exposure; 4) determine cytotoxicity of primary and secondary products of peroxidation in vitro and in vivo; 5) determine if nutritional vitamins E and A, Se, or carotenoids are able to modulate the production of products of PUFA oxidation; 6) assess the antioxidant-metabolic state of the photosensitive cells by determining their content of reduced glutathione--vitamins E and C, and the level of activity of superoxide dismutase and glutathione peroxidase. To accomplish these aims, albino and pigmented rats will be maintained on the AIN-76A formulated diet as a control diet or adjusted to specific levels of nutrients to evaluate their effect on lipid peroxidation. Rearing room illumination will be cyclical (10L:14D) with an intensity of approximately 25 fc. Exposure regimens will be one of the following: 1) 3-8 hrs at 1000 fc, 2) 2-4 days continuously at 200 fc, or 3) 2-6 weeks continuously at 25 fc. Freeze-dried retinas will be microdissected into: "whole retina," neural retina, photoreceptor cells, outer segments, RPE, and choroid. Samples of each layer will be used for the analysis of PUFAs, products of peroxidation or antioxidants by GC or by GC- MS. Traditional biochemical procedures will be used to evaluate specific cellular enzymes and glutathione. Structural analysis will include light and electron microscopy. It may be that virtually everyone is subject to subclinical light damage to their retinas. Daily accumulated light damage appears to be aggravated by nutritional deficiencies and extended exposure to light (i.e., electric illumination). This work seeks to understand the basic mechanisms of retinal phototoxic degeneration in order to better evaluate its importance and to open routes to control it, thus preserving retinal health.

长期目标：识别并最终控制视网膜照射时形成的细胞毒性分子可见光，导致感光细胞退化。这正在测试的理论机制基于脂质的概念过氧化反应和有毒中间体的形成感光细胞，并且在某些条件下，视网膜色素上皮（RPE）。具体目标： 1) 定量亚油酸和二十二碳六烯酸的氢过氧化物和醛已在视网膜和感光细胞中鉴定出将这项研究扩展到发现的其他重要多不饱和脂肪酸的产品在光敏细胞中； 2) 合成质量标记分子为通过 GC-MS 定量过氧化产物的标准； 3）定量光暴露引起的 PUFA 变化； 4）确定过氧化初级产物和次级产物的细胞毒性体外和体内； 5) 确定是否营养维生素E和A， Se 或类胡萝卜素能够调节产品的生产 PUFA氧化； 6）评估抗氧化代谢状态通过测定其还原光敏细胞的含量谷胱甘肽——维生素E和C，以及活性水平超氧化物歧化酶和谷胱甘肽过氧化物酶。为了实现这些目标，白化老鼠和色素老鼠将被维持 AIN-76A 配方饮食作为对照饮食或调整到特定的营养水平以评估其效果关于脂质过氧化。饲养室照明将是循环的 (10L:14D)，强度约为 25 fc。接触治疗方案将是以下之一：1) 1000 fc 3-8 小时，2) 200 fc 下连续 2-4 天，或 3) 连续 2-6 周 25 足球俱乐部。冻干的视网膜将被显微解剖成：“整个视网膜，”神经视网膜，感光细胞，外节，RPE，和脉络膜。每层的样品将用于分析 PUFA、过氧化产物或抗氧化剂的 GC 或 GC- 多发性硬化症。将使用传统的生化程序来评估特定的细胞酶和谷胱甘肽。结构分析将包括光学显微镜和电子显微镜。可能几乎每个人都受到亚临床光的影响视网膜受损。每日累积的光损伤出现营养缺乏和长期接触会加剧照明（即电照明）。这项工作旨在了解视网膜光毒性变性的基本机制为了更好地评估其重要性并开辟通往控制它，从而保持视网膜健康。