Electron Microscopic Studies of Crystalline Lenses

描述(申请人提供)：我们研究计划的长期目标是阐明脊椎动物晶状体的正常形态，因为它与人类晶状体功能有关。这些信息作为进一步研究年龄相关和/或晶体病理变化如何表现为晶体光学质量下降(焦点锐度降低和光散射增加)最终导致特定白内障的基线。在过去的三个授权期中，我们已经表明，根据缝合解剖，有四种不同类型的镜片。缝线复杂程度的变化与晶状体的光学质量有关。此外，我们还展示了发育过程中后缝线的畸形(常染色体隐性视网膜色素变性[ARRP])，由于一些眼科手术(玻璃体切除术)、系统性疾病(糖尿病)以及调节长期神经和行为可塑性的慢性治疗，这些都会导致后囊下白内障(PSC)的形成。更重要的是，我们发现，至少部分PSC可以通过显著恢复晶状体光学质量来预防或逆转。在这笔赠款的未来五年中提出的研究旨在扩大我们以前的研究，并实现以下具体目标：1)在已建立的动物模型中，表征白内障(通常在短期形成的PSC占所有患者的50%)和长期出现的核硬化性白内障(占所有老年患者的50%)作为玻璃体切除或小梁切除并发症的结构/功能关系；2)首次研究了幼年和老年鸟类(鸡)、非灵长类动物、哺乳动物(兔)、灵长类动物(猴子和狒狒)和人类晶状体中晶状体缝线与动态聚焦(调节和非调节)之间的关系；以及3)继续阐明MIP、MP19、Cx46和CX50基因敲除小鼠晶状体发育和生长过程中主要纤维膜蛋白对晶状体功能的贡献。在这些研究中，我们将利用我们实验室开发的改进的十二烷基硫酸钠-断裂标记制备方案，首次确保沿纤维长度(晶状体上和晶状体外缝合)以及整个纤维发育和生长过程中的主要膜蛋白进行免疫标记。所有动物研究的结果在推断人类状况时必须是合格的。然而，如果在上述动物模型研究中，导致PSC、核硬化和先天性白内障形成的因素与人类条件下存在的因素相似，那么通过我们开发并在实验室常规应用的技术，对晶状体结构和功能之间的关系有更多的了解，应该会导致对人类白内障的早期发现和改善临床治疗，而无论其病因是什么。

DESCRIPTION (provided by applicant): The long term objective of our research program is to elucidate the normal morphology in vertebrate lenses as it relates to human lens function. This information serves as the baseline for additional study of how age-related and/or pathological changes in lenses are manifested as compromised lens optical quality (decreased sharpness of focus and increased light scatter) leading ultimately to the development of specific cataracts. In the last three grant periods we have shown that on the basis of sutural anatomy, there are four different types of lenses. Variations in sutural complexity correlate with lens optical quality. Furthermore, we have shown how malformation of posterior sutures during development (autosomal recessive retinitis pigmentosa [ARRP]), as a consequence of some ocular surgery (vitrectomy), systemic disease (diabetes), and chronic treatment to mediate long-lasting neural and behavioral plasticity, all lead to posterior subcapsular cataract (PSC) formation. More importantly, we have found that at least some of these PSCs can be prevented or reversed with significant restoration of lens optical quality. The studies proposed in the next five years of this grant are designed to expand on our previous studies and accomplish the following specific aims: 1) to characterize the structure/function relationship of cataracts (PSCs typically formed in the short term [>50% of all patients) and nuclear sclerotic cataracts that arise in the long term (>50% of all older patients) as a complication of vitrectomy or trabeculectomy in an established animal model; 2) to characterize, for the first time, the relationship between lens sutures and dynamic focusing (accommodation and non-accommodation) in young vs. old avian (chicken), non-primate, mammalian (rabbit), primate (monkey and baboon)and human lenses; and 3) to continue to elucidate the contributions of the major fiber membrane proteins to lens function during development and growth in MIP, MP19, Cx46 and Cx50 knockout mice. In these studies we will utilize an improved preparative protocol for SDS-fracture labelling developed in our laboratory, that guarantees, for the first time, immunolabelling of the major membrane proteins along fiber length (on and off lens sutures) and throughout fiber development and growth. The results of all animal studies must be qualified when extrapolating to the human condition. However, if the factors that are responsible for PSC, nuclear sclerotic and congenital cataract formation in the above studies using animal models are similar to those that exist in the human condition, then a greater understanding of the relationship between lens structure and function afforded by techniques that we have developed and routinely apply in our laboratory, should lead to earlier detection and improved clinical management of cataracts in humans irrespective of their etiopathology.