Nagelhout Teann J, Gamache Daniel A, Roberts Leighann, Brady Milton T, Yanni John M
Alcon Research, Ltd., Fort Worth, TX 76134, USA.
J Ocul Pharmacol Ther. 2005 Apr;21(2):139-48. doi: 10.1089/jop.2005.21.139.
The aim of this study was to establish a clinically relevant short-term animal model of dry eye with utility in identifying compounds with potential therapeutic efficacy.
Rabbit lacrimal glands were injected with the T-cell mitogen Concanavalin A (Con A) and inflammation, tear function, and corneal epithelial cell integrity were subsequently assessed. The inflammatory response was characterized by quantifying biochemical markers of inflammation ex vivo and by confirming inflammatory cell influx by histology. Matrix metalloproteinase-9 (MMP-9) and proinflammatory cytokines IL-1beta, IL-8, and TGF-beta1 were quantified in tissue extracts. Tear function was monitored by measuring tear fluorescein clearance and tear breakup time (TBUT). Corneal epithelial cell integrity was determined by quantifying the uptake of methylene blue dye following the exposure of rabbits to a low-humidity environment. The anti-inflammatory corticosteroid, dexamethasone, was administered topically as indicated for each study.
Histopathologic evaluation of lacrimal glands injected with Con A revealed a pronounced inflammatory process characterized by lymphocytic infiltration, multifocal necrosis, and fibroplasia. Elevated levels of MMP-9 and cytokines IL-1beta, IL-8, and TGF-beta1 were detected in the lacrimal gland and cornea. Inflammation of the rabbit lacrimal gland following an injection of Con A significantly reduced tear clearance and TBUT and increased susceptibility to desiccation-induced corneal damage. Dexamethasone was prophylactically and therapeutically effective in this inflammation model of dry eye, restoring tear function and inhibiting corneal injury following topical ocular application.
Characteristics of this rabbit lacrimal gland inflammation model of dry eye are consistent with the current understanding of dry eye as a local ocular surface inflammatory response to abnormal tear volume and composition. These results suggest that this rabbit model of dry eye may be employed to assess the therapeutic efficacy of mechanistically diverse agents on clinically relevant signs of ocular surface disease. These methods were strategically developed to be applicable for advancing drug discovery for a broad spectrum of dry eye patients.
本研究的目的是建立一种具有临床相关性的短期干眼动物模型，用于鉴定具有潜在治疗效果的化合物。
向兔泪腺注射T细胞有丝分裂原伴刀豆球蛋白A（Con A），随后评估炎症、泪液功能和角膜上皮细胞完整性。通过在体外定量炎症生化标志物以及通过组织学确认炎症细胞浸润来表征炎症反应。在组织提取物中对基质金属蛋白酶-9（MMP-9）和促炎细胞因子白细胞介素-1β（IL-1β）、白细胞介素-8（IL-8）和转化生长因子-β1（TGF-β1）进行定量。通过测量泪液荧光素清除率和泪膜破裂时间（TBUT）来监测泪液功能。在兔暴露于低湿度环境后，通过定量亚甲蓝染料的摄取来确定角膜上皮细胞的完整性。根据每项研究的指示，局部给予抗炎皮质类固醇地塞米松。
对注射Con A的泪腺进行组织病理学评估显示出明显的炎症过程，其特征为淋巴细胞浸润、多灶性坏死和纤维增生。在泪腺和角膜中检测到MMP-9以及细胞因子IL-1β、IL-8和TGF-β1的水平升高。注射Con A后兔泪腺的炎症显著降低了泪液清除率和TBUT，并增加了对干燥诱导的角膜损伤的易感性。地塞米松在这种干眼炎症模型中具有预防和治疗效果，局部眼部应用后可恢复泪液功能并抑制角膜损伤。
这种兔泪腺炎症性干眼模型的特征与目前将干眼理解为对异常泪液量和成分的局部眼表炎症反应一致。这些结果表明，这种兔干眼模型可用于评估作用机制多样的药物对眼表疾病临床相关体征的治疗效果。这些方法经过精心开发，适用于推进针对广泛干眼患者的药物研发。
