Pseudomonas aeruginosa (P. aeruginosa) keratitis is a sight-threatening and rapidly progressive corneal disease. Neutrophils and neutrophil extracellular traps (NETs) are widely thought to play a vital role in hosts’ immune defenses against bacteria, such as P. aeruginosa. The present study aimed to investigate the dynamics of the formation and the role of NETs in P. aeruginosa keratitis. First, scratched corneas of mice models were treated with 1 × 10⁸ colony-forming units (CFU)/ml of P. aeruginosa suspension or normal saline (NS). Second, after 48 h postinfection, the infected corneas were treated with TobraDex, Tobrex, 0.1% dexamethasone, or NS four times a day, respectively. Clinical examination, hematoxylin and eosin (H&E) staining, immunofluorescence staining, scanning electron microscopy, and bacterial burden testing were performed on the corneas. Tobrex reduced neutrophil infiltration and corneal P. aeruginosa burden. Dexamethasone reduced NETs, bacterial burden, and severe neutrophil infiltration. TobraDex produced a greater reduction in the amount of neutrophils, NETs, and bacterial burden and the results of Tobrex-treated group were between them. These findings corresponded with the clinical findings that TobraDex- and Tobrex-treated mice exhibited slight corneal damage, while dexamethasone-treated mice exhibited very severe corneal damage. Cumulatively, our data suggest that NETs may play a dual role of infection control and corneal damage in P. aeruginosa keratitis. Furthermore, combination treatment targeting NET formation and bacteria may serve as a way of improving the clinical outcomes of bacterial keratitis.

铜绿假单胞菌（P.aeruginosa）角膜炎是一种威胁视力并迅速进展的角膜疾病。人们普遍认为嗜中性粒细胞和嗜中性粒细胞胞外捕集器（NETs）在宿主针对铜绿假单胞菌等细菌的免疫防御中起着至关重要的作用。本研究旨在调查铜绿假单胞菌角膜炎的形成动力学和NETs的作用。首先，用1×10 ⁸菌落形成单位（CFU）/ ml铜绿假单胞菌处理小鼠模型的划伤角膜悬浮液或生理盐水（NS）。第二，感染后48小时后，每天分别用TobraDex，Tobrex，0.1％地塞米松或NS处理感染的角膜。对角膜进行了临床检查，苏木精和曙红（H＆E）染色，免疫荧光染色，扫描电子显微镜和细菌负荷测试。Tobrex减少了中性粒细胞浸润和角膜铜绿假单胞菌负担。地塞米松减少了NETs，细菌负担和严重的中性粒细胞浸润。TobraDex使嗜中性粒细胞，NET和细菌负荷的减少更大，而Tobrex治疗组的结果介于两者之间。这些发现与临床发现相对应，即TobraDex和Tobrex治疗的小鼠表现出轻微的角膜损伤，而地塞米松治疗的小鼠表现出非常严重的角膜损伤。累积地，我们的数据表明，NETs在铜绿假单胞菌角膜炎中可能起感染控制和角膜损害的双重作用。此外，针对NET形成和细菌的联合治疗可以作为改善细菌性角膜炎临床结果的一种方式。