Ultrastructural and mechanical effects of collagen cross-linking treatment on human corneo-scleral tissues

S. Choi, G.B. Jung, Y. Cheong, J.H. Shin, K.H. Jin, H.K. Park
Kyung Hee University, KR

Keywords: collagen cross-linking treatment, riboflavin-UVA, corneo-scleral collagens, atomic force microscopy

Summary:

The aim of this study was to quantitatively examine the immediate effects of a photooxidative collagen cross-linking treatment with photosensitizer riboflavin and 370 nm UVA light in in vitro rabbit dermal collagen fibrils. These effects would be measured at the corneo-scleral stroma based on clinical corneal cross-linking procedures on the morphological and mechanical response level using histology, thickness, and atomic force microscopy analyses. Five parameters including the density, area, thickness, adhesion force, and stiffness of corneo-scleral tissues before and after riboflavin-UVA catalyzed collagen cross-linking treatment were investigated. The riboflavin-UVA catalyzed collagen cross-linking treatment led to an increase in the area and density of both corneal (>108%) and scleral (>118%) stromal collagens as well as an increase in tissue thickness (>107%), but it is not significantly. Furthermore, riboflavin-UVA catalyzed collagen cross-linking treatment led to an increased biomechanical response of corneo-sclera; 125% for corneal stiffness and 108% for scleral stiffness, and 124% for corneal adhesion force and 122% for scleral adhesion force, p > 0.05. The collagen cross-linking treatment through riboflavin-sensitized photoreaction may cause morphological and biomechanical property changes in the collagen fibril network of the cornea as well as the sclera, due to the stromal edema and interfibrillar spacing narrowing.