Institute of Functional and Clinical Anatomy, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
Institute of Functional and Clinical Anatomy, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany; Sechenov University, Department of Operative Surgery and Topographic Anatomy, Moscow, Russia.
Ann Anat. 2022 Aug;243:151954. doi: 10.1016/j.aanat.2022.151954. Epub 2022 May 7.
Urea is a component of tear fluid showing a significantly decreased concentration in dry eye disease. The urea content of tear fluid may depend on urea transporters. The purpose of this study was to examine the expression of urea transporter B (UT-B) at the ocular surface and in the lacrimal glands.
UT-B protein and mRNA expression was investigated in human, porcine, and murine samples. Immunohistochemical staining for UT-B was performed on paraffin sections of human, porcine, and murine corneas, eyelids, and lacrimal glands (n = 5 each). Reverse transcriptase polymerase chain reaction was conducted to detect UT-B mRNA in human and murine cornea, conjunctiva, Meibomian gland, and lacrimal gland (n = 5 each).
UT-B protein expression was comparable in all three species. It was found in the corneal epithelium and endothelium, in the conjunctival epithelium, in the end pieces and excretory ducts of the lacrimal gland, Meibomian gland, and in the glands of Moll and Zeis. The glands of Zeis and the Meibomian glands showed intense UT-B signals in the basal layers of the alveolar epithelia and in the cells of the ductal epithelia. UT-B mRNA was detected in all samples analyzed.
UT-B is expressed by the cells and tissues of the ocular surface and in the lacrimal glands. Potential changes in urea transporter expression might have implications for the pathogenesis of dry eye disease. Since comparable results were obtained for all species investigated, the presented findings may open the door for DED-relevant experimentation on porcine and murine model systems.
尿素是泪液的成分之一，在干眼症中其浓度显著降低。泪液中的尿素含量可能取决于尿素转运体。本研究旨在检查眼部表面和泪腺中尿素转运体 B（UT-B）的表达。
在人、猪和鼠的样本中研究了 UT-B 蛋白和 mRNA 的表达。对人、猪和鼠角膜、眼睑和泪腺的石蜡切片进行了 UT-B 的免疫组织化学染色（n=5 个样本）。通过逆转录聚合酶链反应检测了人眼和鼠眼角膜、结膜、睑板腺和泪腺中的 UT-B mRNA（n=5 个样本）。
UT-B 蛋白表达在这三个物种中是可比的。它存在于角膜上皮和内皮、结膜上皮、泪腺的终末段和排泄管、睑板腺以及莫尔氏腺和 Zeis 腺中。Zeis 腺和睑板腺在肺泡上皮的基底层和导管上皮的细胞中显示出强烈的 UT-B 信号。在所有分析的样本中均检测到 UT-B mRNA。
UT-B 由眼部表面的细胞和组织以及泪腺表达。尿素转运体表达的潜在变化可能对干眼症的发病机制有影响。由于对所有研究的物种均获得了可比的结果，因此本研究结果可能为猪和鼠模型系统的干眼症相关实验开辟了道路。
