Edvardsson Rasmussen Jesper, Lundström Patrik, Eriksson Per Olof, Rask-Andersen Helge, Liu Wei, Laurell Göran
Otorhinolaryngology and Head and Neck Surgery, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
Front Mol Neurosci. 2022 Mar 22;15:842132. doi: 10.3389/fnmol.2022.842132. eCollection 2022.
Furosemide is a loop diuretic used to treat edema; however, it also targets the Na-K-Cl cotransporter-1 (NKCC1) in the inner ear. In very high doses, furosemide abolishes the endocochlear potential (EP). The aim of the study was to gain a deeper understanding of the temporal course of the acute effects of furosemide in the inner ear, including the protein localization of Fetuin-A and PEDF in guinea pig cochleae.
Adult guinea pigs were given an intravenous injection of furosemide in a dose of 100 mg per kg of body weight. The cochleae were studied using immunohistochemistry in controls and at four intervals: 3 min, 30 min, 60 min and 120 min. Also, cochleae of untreated guinea pigs were tested for Fetuin-A and PEDF mRNA using RNAscope technology.
At 3 min, NKCC1 staining was abolished in the type II fibrocytes in the spiral ligament, followed by a recovery period of up to 120 min. In the stria vascularis, the lowest staining intensity of NKCC1 presented after 30 min. The spiral ganglion showed a stable staining intensity for the full 120 min. Fetuin-A protein and mRNA were detected in the spiral ganglion type I neurons, inner and outer hair cells, pillar cells, Deiters cells and the stria vascularis. Furosemide induced an increased staining intensity of Fetuin-A at 120 min. PEDF protein and mRNA were found in the spiral ganglia type I neurons, the stria vascularis, and in type I and type II fibrocytes of the spiral ligament. PEDF protein staining intensity was high in the pillar cells in the organ of Corti. Furosemide induced an increased staining intensity of PEDF in type I neurons and pillar cells after 120 min.
The results indicate rapid furosemide-induced changes of NKCC1 in the type II fibrocytes. This could be part of the mechanism that causes reduction of the EP within minutes after high dose furosemide injection. Fetuin-A and PEDF are present in many cells of the cochlea and probably increase after furosemide exposure, possibly as an otoprotective response.
呋塞米是一种用于治疗水肿的袢利尿剂；然而，它也作用于内耳中的钠-钾-氯共转运体-1（NKCC1）。在非常高的剂量下，呋塞米会消除内淋巴电位（EP）。本研究的目的是更深入地了解呋塞米在内耳中的急性作用的时间进程，包括胎球蛋白-A（Fetuin-A）和色素上皮衍生因子（PEDF）在豚鼠耳蜗中的蛋白质定位。
给成年豚鼠静脉注射剂量为每千克体重100毫克的呋塞米。在对照组以及3分钟、30分钟、60分钟和120分钟这四个时间间隔使用免疫组织化学研究耳蜗。此外，使用RNAscope技术检测未处理豚鼠耳蜗中的Fetuin-A和PEDF mRNA。
在3分钟时，螺旋韧带中的II型纤维细胞中的NKCC1染色消失，随后有长达120分钟的恢复期。在血管纹中，NKCC1的染色强度在30分钟后最低。螺旋神经节在整个120分钟内染色强度稳定。在螺旋神经节I型神经元、内毛细胞和外毛细胞、柱细胞、Dieters细胞和血管纹中检测到Fetuin-A蛋白和mRNA。呋塞米在120分钟时诱导Fetuin-A染色强度增加。在螺旋神经节I型神经元、血管纹以及螺旋韧带的I型和II型纤维细胞中发现了PEDF蛋白和mRNA。在柯蒂氏器的柱细胞中PEDF蛋白染色强度较高。呋塞米在120分钟后诱导I型神经元和柱细胞中PEDF染色强度增加。
结果表明呋塞米可迅速诱导II型纤维细胞中NKCC1的变化。这可能是高剂量呋塞米注射后数分钟内导致内淋巴电位降低的机制的一部分。Fetuin-A和PEDF存在于耳蜗的许多细胞中，并且在呋塞米暴露后可能增加，可能作为一种耳保护反应。
