利用交聯反應治療角膜病變之研究

Abstract

核黃素/紫外線膠原蛋白交聯術已普遍得到認可是治療圓錐角膜及其他角膜異位症安全又有效的療法。核黃素於其中扮演光敏劑的角色，對於波長370nm的光能具最大吸收峰值，當其受到波長370nm的紫外光照射、激發時，核黃素會因而產生自由基導致組織中的膠原纖維進行物理交聯，因而使逐漸變薄和弱化的角膜基質被硬化。然而，有鑑於紫外線照射的傷害力，此種光交聯法仍有許多潛在風險。因此，許多研究團隊開始改用化學交聯劑，作為光交聯的替代方案，以提高角膜的機械性質及硬度。在本研究中，我們選擇了三種不同的化學交聯劑，旨在比較這些化學交聯法和核黃素/紫外線交聯法對牛角膜的生物物理、生物化學、生物力學和光譜學性質的影響。研究結果顯示，無論我們使用哪種交聯方法，牛角膜的機械強度都有顯著的變化，對於酵素酶的消化抵抗力也有增加，但是對於角膜的含水行為來講並無太大的改變，此外，從傅立葉轉換紅外光譜的分析結果看來，角膜交聯後力學強度的提升及對酵素酶消化抵抗力的提升很有可能是因為多了碳氫鍵的生成。

Riboflavin/UVA collagen cross-linking has already been recognized as a safe and effective therapy for the progressive keratoconus and other corneal ectatic disorders. The thinning and weakening corneal stroma can be stiffened when the photosensitizer riboflavin excited by UVA at its absorption peak of 370 nm creates free radicals resulting in cross-linking of collagen fibers. However, there are still some potential risks for the corneal and the ocular tissues with UVA irradiation. Therefore, searching other chemical cross-linking alternatives have become emergent to enhance biomechanical properties and stiffness of cornea in addition to riboflavin/UVA collagen cross-linking. In this research, we chose three different chemical cross-linkers and aimed to compare their safety and effectiveness caused by these chemical cross-linking and riboflavin/UVA collagen cross-linking on the biophysical, biochemical, biomechanical and spectroscopy properties of bovine cornea. Our results suggest that there are significant change in the mechanical strength of bovine cornea and its resistance against enzyme digestion in all of the cross-linking methods. However, there is no difference of the hydration behavior of cornea after cross-linking treated among them except the group cross-linked by BDDE. In addition, from the FT-IR spectrum that the enhancement of biomechanical property of cornea and the resistance to enzyme digestion are possibly due to the formation of carbon-oxygen linkage between collagen and cross-linker.