Department of Cardiology, Dong-A University College of Medicine, Busan, Korea.
J Korean Med Sci. 2013 Mar;28(3):402-8. doi: 10.3346/jkms.2013.28.3.402. Epub 2013 Mar 4.
Aquaporins (AQPs) are expressed in myocardium and the implication of AQPs in myocardial water balance has been suggested. We investigated the expression patterns of AQP subtypes in normal myocardium and their changes in the process of edema formation and cardiac dysfunction following myocardial infarction (MI). Immunostaining demonstrated abundant expression of AQP1, AQP4, and AQP6 in normal mouse heart; AQP1 in blood vessels and cardiac myocytes, AQP4 exclusively on the intercalated discs between cardiac myocytes and AQP6 inside the myocytes. However, neither AQP7 nor AQP9 proteins were expressed in CD1 mouse myocardium. Echocardiography revealed that cardiac function was reduced at 1 week and recovered at 4 weeks after MI, whereas myocardial water content determined by wet-to-dry weight ratio increased at 1 week and rather reduced below the normal at 4 weeks. The expression of cardiac AQPs was up-regulated in MI-induced groups compared with sham-operated control group, but their time-dependent patterns were different. The time course of AQP4 expression coincided with that of myocardial edema and cardiac dysfunction following MI. However, expression of both AQP1 and AQP6 increased persistently up to 4 weeks. Our findings suggest a different role for cardiac AQPs in the formation and reabsorption of myocardial edema after MI.
水通道蛋白（AQPs）在心肌中表达，AQPs 在心肌水平衡中的作用已被提出。我们研究了正常心肌中 AQP 亚型的表达模式及其在心肌梗死后水肿形成和心功能障碍过程中的变化。免疫染色显示 AQP1、AQP4 和 AQP6 在正常小鼠心脏中大量表达；AQP1 存在于血管和心肌细胞中，AQP4 仅存在于心肌细胞之间的闰盘上，AQP6 位于心肌细胞内。然而，在 CD1 小鼠心肌中未表达 AQP7 和 AQP9 蛋白。超声心动图显示，心肌梗死后 1 周心功能降低，4 周后恢复，而心肌含水量（以湿重/干重比表示）在 1 周时增加，在 4 周时低于正常。与假手术对照组相比，MI 诱导组的心脏 AQP 表达上调，但它们的时间依赖性模式不同。AQP4 的表达时间与 MI 后心肌水肿和心功能障碍的时间一致。然而，AQP1 和 AQP6 的表达持续增加至 4 周。我们的研究结果表明，心脏 AQP 在 MI 后心肌水肿的形成和重吸收中具有不同的作用。
