LACTATE, PYRUVATE, PH AND K+ IN CORNEAL EDEMA

角膜水肿中的乳酸、丙酮酸、PH 和 K

• 批准号: 3262171
• 负责人: JOSEPH W HUFF
• 金额: $ 7.09万
• 依托单位: UNIVERSITY OF MISSOURI-ST. LOUIS
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-09-30 至 1989-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3262171
• 关键词: acid base balance; cell osmotic pressure; contact lens; cornea edema; corneal endothelium; corneal epithelium; corneal stroma; eye bank /preservation; lactate dehydrogenases; lactates; microelectrodes; microscopy; potassium; pyruvate dehydrogenase; pyruvates; spectrometry

The relative ratio of anaerobic and aerobic corneal carbohydrate metabolism, as indicated by the lactate: pyruvate (L/P) ratio, increases during corneal epithelial hypoxia and contact lens wear, and this is acompanied by ATP depletion. During and following mid-term eyebank storage, corneal energy depletion and lactate accumulation have also been reported to accompany the corneal degradation of endothelial and epithelial function. The proposed experiments are designed to determine whether or not these type of edema are due to a) an osmotic effect of lactate accumulation due to an altered L/P ratio, b) a lactic acidosis, or c) a lactic acidosis accompanied by cellular "rundown" of epithelial and/or stromal K+ gradients. If L, L/P, or stromal pH or K+ activity are altered by simulated contact lens wear, epthelial hypoxia, or eyebank-induced storage in isolated rabbit corneas, these timecourse and reversibility changes will be studied and correlated with corneal thickness changes (swelling or deswelling rates). Furthermore, "stromal" loading in deepithelialized normoxic corneas will be used to determine whether the measured L, pH or K+ activity, placed at a normal stroma, can inhibit endothelium-mediated deturgescenece to account for the edema. If so, then their effects on endothelial hydraulic conductivity will be examined to determine whether the action is on "pump" or "leak". In other experiments two lactate dehydrogenase (LDH) inhibitors (3.2mM sodium oxamate and 3.2mM disodium oxalate) and two pyruvate dehydrogenase (PDH) stimulates (3.2mM sodium dichloracetate and 3.2mM sodium 2-chloropropionate) will be assessed for their ability to prevent or reverse these forms of corneal edema (and the associated ionic effects, if detected above). L and P will be assayed spectrophotometrically in homogenized corneal extracts and expressed both as umoles/g wet weight and as umoles/mg corneal protein. Stormal pH and K+ activity will be expressed in terms of pH and meq/liter, as determined from double barrelled glass liquid ion exchange microelectrodes. Specular microscopy will be used to determine corneal swelling and deswelling rates. Together, these studies will provide insight regarding the etiologies and prevention of contact lens- and eyebank storage-induced corneal edema.

角膜厌氧和需氧的相对比例 碳水化合物代谢，如乳酸：丙酮酸所示 (L/P) 比率，在角膜上皮缺氧期间增加，并且 佩戴隐形眼镜，这会伴随着 ATP 的消耗。 在中期眼库存储期间和之后，角膜能量 据报道，乳酸消耗和乳酸积累也会导致 伴随角膜内皮细胞和上皮细胞的退化 功能。 所提出的实验旨在确定 这些类型的水肿是否是由于 a) 渗透压所致 L/P 比率改变导致乳酸积累的影​​响，b) 乳酸性酸中毒，或 c) 乳酸性酸中毒伴有 上皮和/或基质 K+ 梯度的细胞“流失”。 如果 L、L/P 或基质 pH 或 K+ 活性发生改变 模拟隐形眼镜佩戴、上皮缺氧或 眼库诱导的离体兔角膜储存，这些 将研究时间进程和可逆性变化 与角膜厚度变化（肿胀或 消肿率）。 此外，“基质”加载 去上皮的常氧角膜将用于确定 无论测量的 L、pH 或 K+ 活性，均置于正常条件下 基质，可以抑制内皮介导的水肿 考虑到水肿。 如果是这样，那么它们的影响 将检查内皮水力传导率 确定操作是针对“泵”还是“泄漏”。 在其他方面 实验两种乳酸脱氢酶 (LDH) 抑制剂 (3.2mM 草酸钠和 3.2mM 草酸二钠）和二丙酮酸盐 脱氢酶 (PDH) 刺激（3.2mM 二氯乙酸钠和 3.2mM 2-氯丙酸钠）将被评估其 预防或逆转这些形式的角膜水肿的能力（以及 相关的离子效应（如果上面检测到）。 L 和 P 将 在均质角膜中进行分光光度测定 提取物并表示为umoles/g湿重和 umoles/mg 角膜蛋白。 暴风雨 pH 值和 K+ 活性将 以 pH 值和毫克当量/升表示，由下式确定 双筒玻璃液体离子交换微电极。 镜面显微镜将用于确定角膜肿胀 和消肿率。 这些研究将共同​​提供 关于接触的病因和预防的见解 晶状体和眼库储存引起的角膜水肿。