ABSTRACT

Dry eye disease (DED) is a chronic and progressive lesion on the ocular surface and induces symptoms, such as burning sensation, itchy eyes, heavy eyes, tired eyes, dry feeling, facial flushing, and blurred vision. The present study was performed to develop DED biomarkers using metabolomics in a rat model. DED was induced by injecting scopolamine and exposing rats to a dry condition. Scopolamine (12 mg/kg/day for 7 days) was subcutaneously injected to male Sprague–Dawley rats. The rats were placed in dry condition with air-flow and dehumidifier. Tear volume and tear breakup time (TBUT) were measured, and eyes were examined through fluorescein staining to assess DED. Mucosal damage and immune reactions were also determined. Plasma and urinary endogenous metabolites were determined using ¹H-NMR analysis. Compared with control tear and TBUT levels were significantly decreased in the DED group whereas corneal damage was significantly increased. The levels of interleukins (IL-6) and IL-1β significantly elevated in the cornea and lacrimal glands in the DED group. TNF-α was numerically increased but not significantly different between groups. Pattern recognition using principal component analysis (PCA) and orthogonal projections to latent structure-discriminant analysis (OPLS-DA) of the NMR spectra in global profiling revealed different clusters between DED and control groups. Target profiling demonstrated that PCA and OPLS-DA score plots were separated between DED and controls in plasma and urine. Subsequently, 9 plasma metabolites were selected to examine different clustering between groups, and 26 urinary metabolites were also selected. Plasma metabolites showed a non-significant rising tendency in the DED group. Urinary phenylalanine, phenylacetate, pantothenate, glycine, succinate, methanol, valine, propylene glycol, histidine, threonine, lactate, and acetate were significantly different between control and DED rats. These results may contribute to understanding the metabolic regulation that is involved in DED and might be useful for potential biomarkers related to DED in rats.

摘要

干眼症 (DED) 是眼表的一种慢性进行性病变，会引起烧灼感、眼睛发痒、眼睛沉重、眼睛疲倦、感觉干燥、面部潮红和视力模糊等症状。本研究旨在使用大鼠模型中的代谢组学开发 DED 生物标志物。DED 是通过注射东莨菪碱并将大鼠暴露在干燥条件下诱导的。将东莨菪碱（12 毫克/公斤/天，持续 7 天）皮下注射给雄性 Sprague-Dawley 大鼠。将大鼠置于有空气流动和除湿机的干燥条件下。测量泪液量和泪液破裂时间 (TBUT)，并通过荧光素染色检查眼睛以评估 DED。还测定了粘膜损伤和免疫反应。血浆和尿液内源性代谢物的测定使用¹H-NMR分析。与对照组相比，DED 组的撕裂和 TBUT 水平显着降低，而角膜损伤显着增加。DED组角膜和泪腺中白细胞介素（IL-6）和IL-1β的水平显着升高。TNF-α 在数值上有所增加，但组间没有显着差异。使用主成分分析 (PCA) 和对 NMR 光谱的潜在结构判别分析 (OPLS-DA) 进行正交投影的模式识别揭示了 DED 和对照组之间的不同集群。目标分析表明 PCA 和 OPLS-DA 评分图在血浆和尿液中的 DED 和对照之间是分开的。随后，选择了 9 种血浆代谢物来检查组间的不同聚类，26 种尿液代谢物也被选中。血浆代谢物在 DED 组中显示出不显着的上升趋势。尿液苯丙氨酸、苯乙酸盐、泛酸盐、甘氨酸、琥珀酸盐、甲醇、缬氨酸、丙二醇、组氨酸、苏氨酸、乳酸盐和乙酸盐在对照和 DED 大鼠之间显着不同。这些结果可能有助于了解 DED 中涉及的代谢调节，并可能对与大鼠 DED 相关的潜在生物标志物有用。