ENVIRONMENTAL LIGHT AND RETINAL MEMBRANE DEVELOPMENT

这项建议的长期目标是更好地理解 可见光诱导光感受器细胞损伤的机制 光照后发生的修复和恢复过程。 我们将研究年龄和轻养育环境对 维持一年的大鼠视网膜光损伤 弱周期光或暗的受控条件。我们的重点将是 关于光在核中引发的事件和视觉细胞的反应 作为氧化的标记或标记光感受器细胞 死亡。为了研究强光照射对人体的氧化作用 视网膜，将比较大鼠对光损伤的敏感性 不同年龄，有或没有抗氧化剂前处理。标准 将使用连续光曝光技术，以及曝光 加速光损伤过程的范例。我们将测试 老年大鼠适应饲养条件突变的能力 与幼年动物相比，为了抵抗轻微的伤害， 从微弱的周期光到黑暗，反之亦然。世俗的 光致视网膜损伤与修复的关系及临床意义 将对光照后的恢复进行研究，以了解事件 这会导致视觉细胞死亡或存活。生物化学指标 视觉细胞丢失，包括视紫红质分析和视觉细胞DNA 内容，将由协作形态评估进行补充 对视觉细胞和视网膜色素上皮的损害。我们 将研究DNA损伤的时间进程和相互关系 修复、应激蛋白反应、信使核糖核酸诱导和酶活性 在光照期间和在光照后的黑暗恢复期。 这将通过限制性内切酶的Southern分析来完成 光感受器中表达或不表达的基因片段，通过 溴化乙锭用于视网膜总DNA链断裂的泊松分析 染色琼脂糖凝胶电泳法，并用高效液相色谱法测定氧化 鸟苷核苷。西方的、北方的分析 电泳法分离的视觉转导和热休克蛋白 而mRNAs将与被认为是 对视觉细胞功能很重要。这项建议的具体目的 主要有：(1)测定年龄和抗氧化剂的影响 (二甲基硫脲)强损伤时对特定分子的处理 饲养长达12个月的大鼠在弱循环光或 在黑暗中。(2)确定年龄和光线变化的影响 影响光感受器的特定分子的培养条件 细胞功能和光损伤敏感性。(三)确定时间 暴露后视觉细胞修复和损伤恢复的过程 对有或没有RPE损伤的大鼠进行强烈的可见光照射。这个 光诱导视紫红质介导的脑内事件的特征 年轻和老年大鼠的光感受器可能提供有用的洞察 动物的光损伤机制及其与光损伤的关系 长期光学史与老年性视细胞丧失之间的关系 人类。

The long term objectives of this proposal are a better understanding of the mechanisms of visible light induced photoreceptor cell damage and of the processes of repair and recovery that occur following light exposure. We will study the influences of age and light rearing environment on retinal light damage in rats maintained for up to one year under carefully controlled conditions of weak cyclic light or darkness. Our focus will be on light initiated events in the nucleus and on visual cell responses that serve as markers of oxidation or that mark the photoreceptor cell for death. To examine the oxidative effects of intense light exposure in the retina, comparisons of light damage susceptibility will be made in rats of various ages, with or without antioxidant pretreatment. Standard techniques of continuous light exposure will be used, as well as exposure paradigms that accelerate the light damage process. We will test the ability of older rats to adapt to an abrupt change in rearing conditions and to resist light damage in comparison to young animals, following a change from weak cyclic light to darkness and vice versa. The temporal relationship between light initiated retinal damage and repair and recovery following light exposure will be studied to understand the events which lead to visual cell death or survival. Biochemical measures of visual cell loss, including rhodopsin analysis and visual cell DNA content, will be complemented by collaborative morphological evaluations of damage in the visual cells and in the retinal pigment epithelium. We will study the time course and interrelationships of DNA damage and repair, stress protein responses, mRNA induction and enzyme activities during light and during the dark recovery period following light exposure. This will be accomplished by Southern analysis of restriction enzyme fragments from genes expressed or not expressed in photoreceptors, by Poisson analysis of total retinal DNA strand breaks using ethidium bromide stained agarose gel electrophoresis, and by HPLC determination of oxidized guanosine nucleosides. Western, and Northern analysis of electrophoretically separated visual transduction and heat shock proteins and mRNAs will be used along with kinetic analysis of enzymes thought to be important for visual cell function. The specific aims of this proposal are: (1) To determine the effects of age and antioxidant (dimethylthiourea) treatment on specific molecules during damaging intense light exposure of rats reared for up to 12 months in weak cyclic light or in darkness. (2) To determine the effects of age and a change in light rearing conditions on specific molecules which can impact photoreceptor cell function and light damage susceptibility. (3) To determine the time course of visual cell repair and recovery from damage following exposure to intense visible light in rats with or without RPE damage. The characterization of light induced-rhodopsin mediated events in the photoreceptors of young and older rats may provide useful insights into the mechanisms of light damage in animals and into the relationship between long term light history and age related visual cell loss in humans.