Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea.
Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea.
Invest Ophthalmol Vis Sci. 2018 Jul 2;59(8):3239-3248. doi: 10.1167/iovs.18-23786.
Acanthamoeba keratitis is a well-known intractable corneal infectious disease. We investigated the anti-Acanthamoeba effect of exogenous nitric oxide (NO).
Acanthamoeba castellanii was axenically cultured and exposed to various concentrations of NO donors, such as sodium nitrite, sodium nitroprusside (SNP), and NO-releasing silica nanoparticles (coated in branched polyethylene imine, size:100 nm), for 1 to 7 days (sodium nitrite and SNP: 0, 0.1, 1, 10, 100, and 1000 μM; silica nanoparticles: 0, 6.25, 12.5, 25, 50, and 100 μg/mL). Human corneal epithelial cells (HCECs) were cultured and exposed to sodium nitrite, SNP (0, 0.1, 1, 10, 100, and 1000 μM), and silica nanoparticles for 1, 2, and 3 days.
Sodium nitrite and SNP showed a dose-dependent inhibitory effect on A. castellanii viability. A more prominent inhibitory effect was observed with SNP (less than 10% of organisms survived at 7-day culture with 1000 μM) compared with sodium nitrite. However, more cytotoxicity on HCEC was observed with SNP. NO-releasing silica nanoparticles were successfully internalized into the amoebic cytoplasm and accumulated in large vacuoles. Although blank silica nanoparticles had no inhibitory effect on A. castellanii viability, NO-releasing silica nanoparticles showed a dose-dependent amoebicidal effect. Furthermore, no cystic transformation of A. castellanii was observed under a phase contrast microscope or transmission electron microscope after exogenous NO treatment.
Our results demonstrated the anti-Acanthamoeba effect of exogenous NO. This finding suggests that NO-releasing drug platforms, including nano-carriers, can be a promising therapeutic strategy for Acanthamoeba keratitis.
棘阿米巴角膜炎是一种众所周知的难治性角膜感染性疾病。我们研究了外源性一氧化氮（NO）对棘阿米巴的抗作用。
采用无共生体培养法培养棘阿米巴，并将其暴露于不同浓度的NO 供体中，如亚硝酸钠、硝普酸钠（SNP）和释放 NO 的硅纳米颗粒（涂有支化聚乙烯亚胺，粒径：100nm），作用 1 至 7 天（亚硝酸钠和 SNP：0、0.1、1、10、100 和 1000μM；硅纳米颗粒：0、6.25、12.5、25、50 和 100μg/mL）。培养人角膜上皮细胞（HCEC）并暴露于亚硝酸钠、SNP（0、0.1、1、10、100 和 1000μM）和硅纳米颗粒中 1、2 和 3 天。
亚硝酸钠和 SNP 对棘阿米巴活力表现出剂量依赖性抑制作用。与亚硝酸钠相比，SNP 表现出更显著的抑制作用（7 天培养时，1000μM 组仅有不到 10%的生物存活）。然而，SNP 对 HCEC 的细胞毒性更大。释放 NO 的硅纳米颗粒成功地被内吞到阿米巴细胞质中，并在大空泡中积累。尽管空白硅纳米颗粒对棘阿米巴活力没有抑制作用，但释放 NO 的硅纳米颗粒表现出剂量依赖性杀阿米巴作用。此外，在透射电子显微镜下，用外源性 NO 处理后，棘阿米巴未见囊泡转化。
我们的研究结果证明了外源性 NO 的抗棘阿米巴作用。这一发现表明，包括纳米载体在内的释放 NO 的药物平台可能是棘阿米巴角膜炎的一种有前途的治疗策略。
