Viau Sabrina, Maire Marie-Annick, Pasquis Bruno, Grégoire Stéphane, Fourgeux Cynthia, Acar Niyazi, Bretillon Lionel, Creuzot-Garcher Catherine P, Joffre Corinne
Eye and Nutrition Research Group, UMR1129 FLAVIC, ENESAD, INRA, Université de Bourgogne, Dijon, France.
Graefes Arch Clin Exp Ophthalmol. 2008 Jun;246(6):857-67. doi: 10.1007/s00417-008-0784-9. Epub 2008 Mar 21.
The aim of this study was to set up an animal model of dry eye showing disturbance in several components of the lacrimal functional unit, and to describe the time course of the appearance of clinical signs and inflammatory markers.
Dry eye was induced in 6-week-old female Lewis rats by a systemic and continuous delivery of scopolamine via osmotic pumps implanted subcutaneously. We first determined the appropriate dose of scopolamine (6, 12.5, or 25 mg/day) for 28 days. In a second set of experiments, we determined markers after 1, 2, 3, 7, 10, 17, or 28 days of a 12.5-mg/day dose. Clinical signs of corneal dryness were evaluated in vivo using fluorescein staining. MHC II expression and mucin Muc5AC production were detected on the conjunctival epithelium using immunostaining. The level of IL-1beta, IL-6, TNF-alpha, and IFN-gamma mRNA was evaluated by real-time polymerase chain reaction in conjunctiva and exorbital lacrimal gland (LG). Lipids were extracted from the exorbital LG for fatty acid analysis.
Daily scopolamine doses of 12.5 mg and 25 mg applied for a 28-day period induced keratitis, a decrease in Muc5AC immunostaining density in the conjunctival epithelium, and modifications in the fatty acid composition of the exorbital LG. Animals treated with a 12.5-mg/day dose of scopolamine exhibited an increase in corneal fluorescein staining after 2, 10, and 28 days. All animals exhibited unilateral or bilateral keratitis after 17 days. In the conjunctival epithelium, a significant decrease in Muc5AC immunostaining density was observed at early and late time points, and MHC II expression tended to be increased after 1, 7, 10, and 28 days, without reaching statistical significance. The levels of TNF-alpha, IL-1beta and IL-6 mRNA were increased with scopolamine treatment in both conjunctiva and exorbital LG. Arachidonic acid and the Delta5 desaturase index were significantly increased in the exorbital LG of dry eye animals at each time point.
This systemic and continuous scopolamine-induced model of dry eye in the rat may represent a helpful tool to investigate moderate dry eye, and makes a contribution in the field of dry eye study.
本研究的目的是建立一种泪液功能单位多个成分出现紊乱的干眼动物模型，并描述临床体征和炎症标志物出现的时间进程。
通过皮下植入渗透泵全身持续给予东莨菪碱，诱导6周龄雌性Lewis大鼠患干眼。我们首先确定了连续28天给予东莨菪碱的合适剂量（6、12.5或25毫克/天）。在第二组实验中，我们确定了给予12.5毫克/天剂量1、2、3、7、10、17或28天后的标志物。使用荧光素染色在体内评估角膜干燥的临床体征。使用免疫染色检测结膜上皮细胞上的MHC II表达和粘蛋白Muc5AC的产生。通过实时聚合酶链反应评估结膜和眶外泪腺（LG）中IL-1β、IL-6、TNF-α和IFN-γ mRNA的水平。从眶外泪腺中提取脂质用于脂肪酸分析。
连续28天每天给予12.5毫克和25毫克东莨菪碱可诱发角膜炎，结膜上皮细胞中Muc5AC免疫染色密度降低，眶外泪腺脂肪酸组成发生改变。给予12.5毫克/天剂量东莨菪碱治疗的动物在第2、10和28天后角膜荧光素染色增加。17天后所有动物均出现单侧或双侧角膜炎。在结膜上皮细胞中，在早期和晚期时间点观察到Muc5AC免疫染色密度显著降低，MHC II表达在第1、7、10和28天后有增加趋势，但未达到统计学意义。在结膜和眶外泪腺中，东莨菪碱治疗后TNF-α、IL-1β和IL-6 mRNA水平升高。在每个时间点，干眼动物眶外泪腺中的花生四烯酸和Δ⁵去饱和酶指数均显著升高。
这种全身连续给予东莨菪碱诱导的大鼠干眼模型可能是研究中度干眼的有用工具，为干眼研究领域做出了贡献。
