Biomechanical effect of ultraviolet-A-riboflavin cross-linking on simulated human corneal stroma model and its correlation with changes in corneal stromal microstructure.
Biomechanics
Corneal cross-linking
Human corneal stroma
Transmission electron microscopy
Journal
Experimental eye research
ISSN: 1096-0007
Titre abrégé: Exp Eye Res
Pays: England
ID NLM: 0370707
Informations de publication
Date de publication:
08 2020
08 2020
Historique:
received:
11
02
2020
revised:
11
05
2020
accepted:
02
06
2020
pubmed:
23
6
2020
medline:
14
1
2021
entrez:
23
6
2020
Statut:
ppublish
Résumé
In this study, we established an experimental human corneal stroma model of simulated cornea tissue composed of thin anterior cornea strips layers obtained from small incision lenticular extraction (SMILE) surgery. We investigated the biomechanical effect of ultraviolet-A- riboflavin cross-linking at different depths of corneal stroma model and correlated it with stromal microstructural changes examined by transmission electron microscopy (TEM). Corneal strips were harvested from fresh human corneal lenticules obtained after SMILE surgery. Experimental models (n = 34) were established by superimposing the corneal lenticule strips until their thickness reached close to 500 μm. Corneal cross-linking (CXL) was performed subsequently using standard or accelerated protocol. Elasticity and viscosity were quantified using stress-strain extensometer. TEM was used to visualize the collagen fiber diameter and interfibrillar spacing. The relative change in Young's modulus (rel. ΔE) decreased nonlinearly with increasing stromal depth both in the standard and accelerated groups. Compared to the sham controls, the rel. ΔE in standard and accelerated CXL groups increased significantly in the anterior 400 μm and 275 μm depth, respectively. Also, the relative change in stress (rel. ΔS) was significantly lower after standard and accelerated CXL compared to sham controls. Depth analysis showed similar results for the elastic effect. TEM images showed a small, non-significant increase in fibril diameter. The interfibrillar spacing decreased significantly after standard and accelerated CXL in the anterior-mid stromal region. We noted that the increase of corneal stiffness correlated with decrease in interfibrillar spacing after CXL. The stiffening effect was depth dependent. The effect of accelerated CXL was less in the deep corneal stromal regions compared to standard CXL.
Identifiants
pubmed: 32565111
pii: S0014-4835(20)30368-7
doi: 10.1016/j.exer.2020.108109
pii:
doi:
Substances chimiques
Cross-Linking Reagents
0
Photosensitizing Agents
0
Collagen
9007-34-5
Riboflavin
TLM2976OFR
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
108109Informations de copyright
Copyright © 2020. Published by Elsevier Ltd.