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: 3262175
• 负责人: JOSEPH W HUFF
• 金额: $ 2.12万
• 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 1988-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3262175
• 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.

角膜厌氧菌与需氧菌的相对比值 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， 接触透镜磨损，这是伴随着ATP耗竭。 在中期眼库储存期间和之后，角膜能量 也有报道说， 伴随角膜内皮和上皮的降解 功能 所提出的实验旨在确定 这些类型水肿是否是由于a）渗透性 L/P比改变对乳酸积累的影响，B） 乳酸酸中毒，或c）乳酸酸中毒伴有 上皮和/或基质K+梯度的细胞“下降”。 如果L、L/P或基质pH或K+活性被改变， 模拟接触透镜配戴、上皮缺氧，或 在离体兔角膜中眼库诱导的储存，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 去溶胀率）。 此外，“基质”加载在 将使用深层上皮化的含氧量正常的角膜来确定 无论是测量的L、pH或K+活性，置于正常 基质，可以抑制内皮介导的去肿胀， 导致了水肿 如果是这样，那么它们对 将检查内皮水力传导性， 确定操作是在“泵”还是“泄漏”上。 换句 实验两种乳酸脱氢酶（LDH）抑制剂（3.2mM 草氨酸钠和3.2mM草酸二钠）和两种丙酮酸盐 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，如果上面检测到的话）。 L和P将 在均质化角膜中用荧光光度法测定 提取物，并表示为微摩尔/克湿重和 umoles/mg角膜蛋白。 风暴的pH值和K+活性将 以pH和meq/升表示，由 双管玻璃液体离子交换微电极。 将使用镜面反射显微镜检查确定角膜肿胀 和去膨胀率。 这些研究将提供 关于接触的病因和预防的见解 透镜和眼库储存诱导的角膜水肿。