CONTROL OF CELL DIVISION IN THE OCULAR LENS

对透镜上皮细胞年龄相关性变化的理解是重要的 因为在美国，每10例新的失明病例中就有1例是由 老年性白内障 这项工作的长期目标是确定 白内障前和伴随白内障的上皮功能变化 形成和老化。 这一资料应进一步澄清 上皮细胞在维持透镜透明度中的作用。 长期目标是确定：1）调节有丝分裂的因素 在体内和体外的透镜上皮细胞中，2）透镜 细胞解毒H2O2，和3）如果响应生长因子和能力 对H2O2的解毒能力随着年龄的增长而变化。 具体目标是确定垂体切除术的影响， 甲状腺切除术和营养不良对眼透镜有丝分裂的影响。 将分析上皮细胞的整体切片，并将有丝分裂的细胞数量 图像和DNA合成细胞定量。 IGF、T3和T4水平 将通过放射免疫测定法和血清的有丝分裂原性进行测量 将在培养的透镜细胞上测定处理的动物。 兔和人透镜细胞在体外长期生长的条件 将研究无血清培养基。 透镜细胞对 多肽生长因子和增强促有丝分裂性的因子 将测定这些肽。 结合位点的数量和 碘化胰岛素在年轻和年轻细胞上的表观解离常数 将对老兔子进行定量。 免疫学技术和分子生物学 将使用探针来证明晶状体特异性功能的保留 在培养的细胞中。 青年和老年兔透镜上皮细胞解毒机制的研究 将测定H2O2。 重点将放在GSH的作用 氧化还原循环和酶，例如GSH还原酶，GSH过氧化物酶，和 超氧化物歧化酶，这可能会随着年龄的增长而受损。 线路将 建立从小鼠编程发展白内障和年龄匹配 非白内障对照，以确定 可能代表白内障前期和白内障状况的上皮。 的 6月龄和1岁龄小鼠透镜细胞对H2O2的解毒能力 将被确定。 TEM技术将用于定位过氧化氢酶， 过氧化物酶在正常和H2O2处理的透镜上皮中的表达。

An understanding of age-related changes in the lens epithelium is important since one in ten new cases of blindness in the United States is caused by senile cataract. The long-term objective of this work is to identify functional changes in the epithelia which precede and accompany cataract formation and aging. This information should further clarify the role of epithelial cells in the maintenance of lens transparency. The long-term goals are to determine: 1) the factors that regulate mitosis in lens epithelia in vivo and in vitro, 2) the mechanism by which lens cells detoxify H2O2, and 3) if the response to growth factors and ability to detoxify H2O2 changes with age. Specific aims are to determine the influence of hypophysectomy, thyroidectomy and under-nutrition on mitosis in the ocular lens. Whole-mounts of the epithelium will be analyzed and the number of mitotic figures and DNA synthesizing cells quantitated. Levels of IGF, T3, and T4 will be measured via radioimmunoassay and the mitogenicity of serum from treated animals will be determined on cultured lens cells. The requirements for long-term growth of rabbit and human lens cells in serum-free medium will be investigated. The response of lens cells to polypeptide growth factors and to factors that enhance the mitogenicity of these peptides will be determined. The number of binding sites and apparent dissociation constant of iodinated insulin on cells from young and old rabbits will be quantitated. Immunological techniques and molecular probes will be used to demonstrate the retention of lens-specific function in cultured cells. The mechanism by which lens epithelia from young and old rabbits detoxifies H2O2 will be determined. Emphasis will be placed on the role of the GSH redox cycle and on enzymes, e.g. GSH reductase, GSH peroxidase, and superoxide dismutase, that may be impaired with age. Lines will be established from mice programmed to develop cataracts and from age-matched non-cataractous controls in an effort to determine changes in the epithelium that may typify precataractous and cataractous conditions. The H2O2 detoxifying ability of lens cells from 6-month and 1-year-old mice will be determined. TEM techniques will be used to localize catalase and peroxidase in normal and H2O2-treated lens epithelia.