Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China.
Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China; Department of Ophthalmology, Cangzhou Central Hospital, Cangzhou, China.
Cytokine. 2023 Nov;171:156356. doi: 10.1016/j.cyto.2023.156356. Epub 2023 Sep 18.
To investigate the antifungal and anti-inflammatory effects of quercetin in Aspergillus fumigatus (A. fumigatus) keratitis.
Draize eye test was performed in mice to evaluate the toxicity of quercetin, and the antifungal effects on A. fumigatus were assessed via scanning electron microscopy (SEM), propidium iodide uptake, and adherence assay. In fungal keratitis (FK) mouse models, immunostaining was performed for investigating toll-like receptor 4 (TLR-4) expression and macrophage infiltration. Real-time PCR, ELISA, and Western blot were used to evaluate the expression of pro-inflammatory factors IL-1β, TNF-α, and IL-6 in infected RAW264.7 cells. Cells were also treated with TLR-4 siRNA or agonist CRX-527 to investigate mechanisms underlying the anti-inflammatory activity of quercetin.
Quercetin at 32 μM was non-toxic to corneal epithelial and significantly inhibited A. fumigatus growth and adhesion, and also altered the structure and reduced the number of mycelia. Quercetin significantly reduced macrophage infiltration in the mouse cornea, and attenuated the expression of TLR-4 in the corneal epithelium and stroma of mice with keratitis caused by A. fumigatus. In RAW264.7 cells infected by A. fumigatus, quercetin downregulated TLR-4 along with pro-inflammatory factors IL-1β, TNF-α, and IL-6. RAW cells with TLR-4 knockdown had reduced expression of factors after A. fumigatus infection, which was decreased even further with quercetin treatment. In contrast, cells with CRX-527 had elevated inflammatory factors compared to control, which was significantly attenuated in the presence of quercetin.
Quercetin plays a protective role in mouse A. fumigatus keratitis by inhibiting fungal load, disrupting hyphae structure, macrophage infiltration, and suppressing inflammation response in macrophages via TLR-4 mediated signaling pathway.
研究槲皮素对烟曲霉（A. fumigatus）角膜炎的抗真菌和抗炎作用。
通过 Draize 眼试验评估槲皮素的毒性，通过扫描电子显微镜（SEM）、碘化丙啶摄取和黏附试验评估其对烟曲霉的抗真菌作用。在真菌性角膜炎（FK）小鼠模型中，通过免疫染色法检测 Toll 样受体 4（TLR-4）表达和巨噬细胞浸润。采用实时 PCR、ELISA 和 Western blot 法检测感染 RAW264.7 细胞后促炎因子白细胞介素 1β（IL-1β）、肿瘤坏死因子-α（TNF-α）和白细胞介素 6（IL-6）的表达。还通过 TLR-4 siRNA 或激动剂 CRX-527 处理细胞，以研究槲皮素抗炎活性的作用机制。
32μM 槲皮素对角膜上皮无毒性，显著抑制烟曲霉生长和黏附，并改变菌丝结构和减少菌丝数量。槲皮素显著减少小鼠角膜中的巨噬细胞浸润，并减轻烟曲霉诱导角膜炎小鼠角膜上皮和基质中 TLR-4 的表达。在被烟曲霉感染的 RAW264.7 细胞中，槲皮素下调 TLR-4 及其下游促炎因子 IL-1β、TNF-α 和 IL-6。感染烟曲霉后，TLR-4 敲低的 RAW 细胞因子表达减少，用槲皮素处理后进一步减少。相反，用 CRX-527 处理的细胞与对照相比炎症因子升高，而用槲皮素处理后则明显降低。
槲皮素通过抑制真菌负荷、破坏菌丝结构、巨噬细胞浸润以及通过 TLR-4 介导的信号通路抑制巨噬细胞中的炎症反应，在烟曲霉诱导的小鼠角膜炎中发挥保护作用。
