LACTATE, PYRUVATE, PH AND K+ IN CORNEAL EDEMA

无氧角膜与有氧角膜的相对比例 碳水化合物代谢，如乳酸所示：丙酮酸 (L/P)比值，在角膜上皮缺氧和 隐形眼镜佩戴，并伴随着ATP耗竭。 在中期眼库储存期间和之后，角膜能量 耗竭和乳酸积累也被报告为 伴随着角膜内皮和上皮细胞的降解 功能。拟议中的实验旨在确定 无论这些类型的浮肿是否由a)渗透性引起 L/磷比值改变对乳酸蓄积的影响，b) 乳酸中毒，或c)乳酸中毒伴发 上皮性和/或间质性K+梯度的细胞“破损”。 如果L、L/P或基质pH或K+活性因 模拟配戴隐形眼镜，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，并 与角膜厚度变化(肿胀或 脱水率)。此外，“基质”加载到 深度石化的常氧角膜将被用来确定 无论是测得的L、pH还是K+活度，放置在正常 间质，可抑制血管内皮细胞介导的去肿胀 导致了水肿症。如果是这样，那么它们对 将检测内皮细胞的水力传导性，以 确定操作是在“泵”上还是“泄漏”上。在其他 试验两种乳酸脱氢酶(LDH)抑制剂(3.2 mM 草酸钠和3.2 mM草酸二钠)和两个丙酮酸 脱氢酶(PDH)刺激(3.2 mM二氯乙酸钠和 3.2 mM 2-氯丙酸钠)将被评估为 预防或逆转这些形式的角膜水肿的能力(和 相关离子效应，如果上面检测到的话)。L和P·威尔 用分光光度法测定匀浆角膜中的含量 提取物和表示为每克湿重的分子数和 Umoles/mg角膜蛋白。暴风雨的pH值和K+活度将 以酸碱度和MEQ/升表示，由 双桶玻璃液体离子交换微电极。 将使用镜面显微镜来确定角膜肿胀。 和脱水率。总而言之，这些研究将提供 对接触的病因和预防的洞察 晶状体和眼库储存所致的角膜水肿。

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.