Wang Xiaokun, Majumdar Shoumyo, Ma Garret, Sohn Jeeyeon, Yiu Samuel C, Stark Walter, Al-Qarni Awad, Edward Deepak P, Elisseeff Jennifer H
Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States 2Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, Maryland, United States.
Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, Maryland, United States 3Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States.
Invest Ophthalmol Vis Sci. 2017 Aug 1;58(10):3887-3895. doi: 10.1167/iovs.16-21292.
To evaluate the crosslinking effect of functionalized chondroitin sulfate (CS) in an ex vivo rabbit cornea model.
Chondroitin sulfate molecules were chemically modified with the N-hydroxysuccinimide (NHS) group. Enucleated rabbit eyes were crosslinked with 2, 5, or 10 mg/mL CS-NHS solution for 30 or 60 minutes. The CS-NHS penetration, corneal swelling ratio, Young's modulus, and ultrastructure of the crosslinked corneas were characterized. In addition, rabbit corneas were further treated with a collagenase-chondroitinase solution to create an ex vivo keratoconus (KC)-like model. The KC model corneas were crosslinked with a standard riboflavin-ultraviolet (UV) method or alternatively with CS-NHS. Corneal mechanics, ultrastructure, and keratocyte gene expression were evaluated after UV and CS-NHS crosslinking.
CS-NHS effectively penetrated into the corneal stroma within 60 minutes of treatment initiation. CS-NHS crosslinking reduced the swelling ratio by 35%, increased Young's modulus by 20%, and increased collagen fibril diameter and density. CS-NHS crosslinking improved corneal mechanics of KC model corneas to levels comparable to those with UV crosslinking. Moreover, CS-NHS crosslinking demonstrated significant downregulation of proinflammatory gene expression of keratocytes, indicating a potential protective effect imparted by CS-NHS during crosslinking.
Our results demonstrated that CS-NHS can reinforce normal and KC model corneal mechanics, and restore collagen density and alignment in KC model corneas without causing extensive keratocyte apoptosis and proinflammatory gene upregulation. Therefore, CS-NHS crosslinking can potentially provide an effective, safe, and biocompatible means of corneal reinforcement.
在体外兔角膜模型中评估功能化硫酸软骨素（CS）的交联效果。
用N - 羟基琥珀酰亚胺（NHS）基团对硫酸软骨素分子进行化学修饰。将摘除的兔眼用2、5或10 mg/mL的CS - NHS溶液交联30或60分钟。对交联角膜的CS - NHS渗透率、角膜肿胀率、杨氏模量和超微结构进行表征。此外，用胶原酶 - 软骨素酶溶液进一步处理兔角膜，以建立体外圆锥角膜（KC）样模型。KC模型角膜用标准核黄素 - 紫外线（UV）方法或CS - NHS进行交联。在UV和CS - NHS交联后评估角膜力学、超微结构和角膜细胞基因表达。
CS - NHS在治疗开始后60分钟内有效渗透到角膜基质中。CS - NHS交联使肿胀率降低了35%，杨氏模量增加了20%，并增加了胶原纤维直径和密度。CS - NHS交联将KC模型角膜的角膜力学改善到与UV交联相当的水平。此外，CS - NHS交联显示角膜细胞促炎基因表达显著下调，表明CS - NHS在交联过程中具有潜在的保护作用。
我们的结果表明，CS - NHS可以增强正常和KC模型角膜的力学性能，并恢复KC模型角膜中的胶原密度和排列，而不会引起广泛的角膜细胞凋亡和促炎基因上调。因此，CS - NHS交联可能提供一种有效、安全且生物相容的角膜强化方法。
