Purpose

Allergic conjunctivitis is the most common cause leading to ocular redness (OR). Herein, using an animal model of allergic OR, we evaluated the therapeutic efficacy of topical blockade of substance P (SP) in treating red eye.

Methods

Allergic OR was induced in guinea pigs with topical histamine. Ocular SP was blocked using a specific SP receptor (neurokinin-1 receptor, NK1R) antagonist, L-703,606, via topical application 10 min before or 10 min after histamine instillation. Animal eyes were examined and a series of images were taken for up to 60 min post-OR induction. The severity of redness was analyzed using the quantitative ocular redness index (ORI). At the end of clinical examination, conjunctival tissues were collected for histological examination of conjunctival blood vessels and infiltrating eosinophils and neutrophils. In addition, SP concentration was quantified in the tear fluid and expression levels of inflammatory cytokines were assessed in the conjunctival tissues.

Results

Topical histamine application successfully induced red eye, evidenced by the significantly increased ORI during the observation period, with peak values at 10 min, along with significantly increased levels of SP in the tears. Topical treatment with L-703,606, either before histamine application or at the time of peak ORI, effectively reduced ORI and suppressed conjunctival blood vessel dilation, along with decreased eosinophil and neutrophil infiltration, and inflammatory cytokine expression in the conjunctiva, as well as reduced SP levels in the tears.

Conclusions

Topical blockade of SP effectively prevents and treats allergy-related ocular redness by suppressing blood vessel dilation and allergic inflammation.

中文翻译：

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局部P物质阻断对实验性过敏性红眼的治疗效果

目的

过敏性结膜炎是导致眼睛发红 (OR) 的最常见原因。在此，我们使用过敏性眼病动物模型，评估了局部P物质（SP）阻断治疗红眼的疗效。

方法

用局部组胺诱导豚鼠发生过敏性 OR。在组胺滴注前 10 分钟或组胺滴注后 10 分钟，通过局部应用，使用特异性 SP 受体（神经激肽-1 受体，NK1R）拮抗剂 L-703,606阻断眼部 SP 。在手术诱导后长达 60 分钟内检查动物眼睛并拍摄一系列图像。使用定量眼部发红指数（ORI）分析发红的严重程度。临床检查结束时，收集结膜组织，对结膜血管和浸润性嗜酸性粒细胞、中性粒细胞进行组织学检查。此外，还对泪液中的 SP 浓度进行了定量，并评估了结膜组织中炎症细胞因子的表达水平。

结果

局部应用组胺成功诱发红眼，观察期间 ORI 显着增加（10 分钟达到峰值），泪液中 SP 水平显着增加。在组胺应用之前或 ORI 峰值时，使用 L-703,606 进行局部治疗，可有效降低 ORI 并抑制结膜血管扩张，同时减少嗜酸性粒细胞和中性粒细胞浸润，减少结膜中炎症细胞因子的表达，并减少SP眼泪中的水平。

结论

局部阻断 SP 可通过抑制血管扩张和过敏性炎症来有效预防和治疗过敏相关的眼部发红。