MOLECULAR BIOLOGY OF DIABETIC CATARACT FORMATION

描述（改编自申请人摘要）：糖尿病性白内障是一种 严重和代价高昂的全球性健康问题。细胞内渗透胁迫 与糖尿病性白内障的病因有关。的定义 导致并发症的基本分子和细胞过程的顺序 糖尿病性白内障的发病率尚未确定。有机物的积累 渗透剂（山梨糖醇、肌醇、牛磺酸）通常保护透镜免受 通过维持细胞内渗透压稳态来调节渗透压失衡。在 在维持透镜内环境稳定的过程中，透镜上皮层保存 本身通过利用几种渗透补偿机制，而 皮下纤维细胞，可能是因为神经调节能力减弱， 肿胀和水泡。为了获得一个现实的观点的病理生理影响， 一种新的糖尿病性白内障转基因动物模型 对探讨渗透压增高的发病机制和治疗有重要意义 白内障形成我们成功地将牛 钠/肌醇协同转运蛋白基因（bSMIT）， 显示转基因在发育中的透镜纤维中功能性表达。Lens 纤维肿胀和随后的白内障形成提供了一种生理学上的 模拟人类糖尿病性白内障进展的替代物。小心 对小鼠透镜区域发育和早发性肿胀的仔细检查允许 验证透镜纤维不能 监管机构。转基因植物的分子生物学和病理生理学 显示糖尿病性白内障的小鼠模型将通过关联 通过原位杂交和偶联反向杂交测定bSMIT基因表达水平 转录/聚合酶链反应与晶状体内的内容， 游离肌醇。透镜形态学之后将是光和电子 使用显微镜评价转基因和非转基因同窝仔 胚胎晶状体通过六个月大的老鼠的晶状体。低 转基因表达小鼠，正常饲养时不形成透镜混浊 和饮食，将通过补充肌醇的饮食来这样做。的 确定糖尿病患者病理生理学中的事件顺序 白内障形成将确定干预部位， 开发创新的药物制剂，以预防或阻止 糖尿病性白内障的进展。其中一种干预措施是激活氯化物 通道，其增强氯化物排出和肌醇流出。本研究 建议测试增强肌醇流出的潜在有用性 通过氯离子通道作为药物治疗的手段， 渗透胁迫

DESCRIPTION (Adapted from applicant's abstract): Diabetic cataract is a significant and costly worldwide health problem. Intracellular osmotic stress has been implicated in the etiology of diabetic cataract. The definition of the sequence of basic molecular and cellular processes leading to the complications of diabetic cataract have yet to be established. The accumulation of organic osmolytes (sorbitol, myo-inositol, taurine) normally protects the lens against osmotic imbalance by maintaining intracellular osmotic homoeostasis. In the course of maintaining lens homeostasis, the lens epithelial layer preserves itself by utilizing several osmotic compensatory mechanisms, whereas the subjacent fiber cells, likely because of a diminished capacity to osmoregulate, swell and bleb. To obtain a realistic view of the pathophysiological impact of osmotic stress on diabetic cataract formation, a novel transgenic animal model has been developed useful to exploring the pathogenesis and therapy of osmotic cataractogenesis. We have successfully introduced the bovine sodium/myo-inositol cotransporter gene (bSMIT) in several mouse lines and have shown the transgene is functionally expressed in developing lens fibers. Lens fiber swelling and consequent cataractous formation provide a physiological surrogate that simulates the progression of human diabetic cataract. Careful scrutiny of mouse lens regional development and early-onset swelling allows for verification of the hypothesis that the lens fibers are incapable of osmoregulation. The molecular biology and the pathophysiology of the transgenic mouse model exhibiting diabetic cataract will be linked by correlating the level of bSMIT gene expression via in situ hybridization and coupled reverse transcription/polymerase chain reaction with the intralenticular content of free myo-inositol. Lens morphology will be followed by light and electron microscopic evaluation of transgenic and nontransgenic littermates using embryonic lenses up through lenses from six month-old mice. Low transgene-expressing mice, which do not form lens opacities with normal rearing and diet, will be made to do so with a myo-inositol supplemented diet. The determination of the sequence of events in the pathophysiology of diabetic cataract formation will identify sites of intervention and allow for the development of innovative pharmacological agents to prevent or halt the progression of diabetic cataract. One such intervention is to activate chloride channels, which enhances both chloride exit and myo-inositol efflux. This study proposes to test the potential usefulness of enhancing myo-inositol efflux through chloride channels as a means for drug therapy to relieve intrafiber osmotic stress.