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Invest Ophthalmol Vis Sci. 2020 Feb 7;61(2):7. doi: 10.1167/iovs.61.2.7.
Confirm that the corneal endothelial pump uses a lactate-coupled water efflux mechanism.
Corneal thickness, lactate efflux, and stromal [lactate] were measured in de-epithelialized swollen and nonswollen ex vivo-mounted rabbit corneas perfused with bicarbonate-rich and bicarbonate-free Ringers, ouabain, or acetazolamide to determine if the relationships among these parameters were similar to previous data using intact corneas. The role of barrier function was tested by perfusion with calcium-free EGTA. Predictions of [lactate] in endothelial dystrophy were examined in the Slc4a11 knock out mouse.
De-epithelialized corneal swelling, lactate efflux, and stromal [lactate] in response to bicarbonate-free Ringers, ouabain, and acetazolamide perfusion had the same relationship as in intact corneas. The absolute amount of lactate efflux and stromal [lactate] in the de-epithelialized corneas was about half of intact corneas. De-epithelialized, swollen corneas deswelled fully with bicarbonate-rich, partially in the presence of acetazolamide, but continued to swell with bicarbonate-free or ouabain. The relationship among corneal thickness, lactate efflux, and [lactate] was the same as with nonswollen de-epithelialized corneas. In intact corneas swollen by perfusion with calcium-free EGTA, the relationship between swelling and lactate flux was the inverse of control corneas. The relationship between corneal swelling and [lactate] of intact corneas exposed to ouabain, but perfused with 7 mM lactate to simulate aqueous humor, was the same as without lactate. Corneal [lactate] in Slc4a11 knock out was twice that of wild type.
The corneal endothelial pump works via a lactate efflux mechanism that requires an intact osmotic barrier.
证实角膜内皮泵采用乳酸盐偶联的水外排机制。
对去上皮化肿胀和非肿胀的离体兔角膜进行测量，以评估角膜厚度、乳酸盐外排和基质[乳酸盐]，所用方法为用碳酸氢盐丰富和不含碳酸氢盐的林格氏液、哇巴因或乙酰唑胺对其进行灌流，以确定这些参数之间的关系是否与之前使用完整角膜的研究数据相似。通过用无钙 EGTA 进行灌流来检测屏障功能的作用。在 Slc4a11 敲除小鼠中检查内皮营养不良的 [乳酸盐]预测。
去上皮化角膜肿胀、对不含碳酸氢盐的林格氏液、哇巴因和乙酰唑胺灌流的乳酸盐外排以及基质[乳酸盐]的反应与完整角膜相同。去上皮化角膜的乳酸盐外排量和基质[乳酸盐]的绝对量约为完整角膜的一半。用碳酸氢盐丰富的溶液，去上皮化、肿胀的角膜完全去肿胀，部分情况下用乙酰唑胺，但用不含碳酸氢盐或哇巴因时继续肿胀。角膜厚度、乳酸盐外排和[乳酸盐]之间的关系与非肿胀的去上皮化角膜相同。在通过用无钙 EGTA 灌流肿胀的完整角膜中，肿胀与乳酸盐通量之间的关系与对照角膜相反。用哇巴因使完整角膜肿胀，但用 7mM 乳酸盐模拟房水进行灌流时，角膜肿胀与[乳酸盐]之间的关系与无乳酸盐时相同。Slc4a11 敲除的角膜 [乳酸盐]是野生型的两倍。
角膜内皮泵通过需要完整渗透屏障的乳酸盐外排机制起作用。
