Role of corneal epithelium in riboflavin/ultraviolet-A mediated corneal cross-linking treatment in rabbit eyes.
OBJECTIVE
To evaluate the role of corneal epithelium in riboflavin/ultraviolet-A (UVA) mediated corneal collagen cross-linking treatment.


METHODS
Fifty New Zealand rabbits were divided into 5 groups: UVA treatment with or without corneal epithelium, UVA+riboflavin treatment with or without corneal epithelium, and control without any treatment. All rabbits were sacrificed after irradiation and subsequently 4 mm × 10 mm corneal strips were harvested for biomechanical evaluation.


RESULTS
UVA irradiation alone did not enhance the maximal stress and Young's modulus of corneal specimens with (3.15 ± 0.56 mpa, 1.00 ± 0.09 mpa) or without (3.53 ± 0.85 mpa, 0.94 ± 0.21 mpa) the corneal epithelium, compared to specimens in the control group (4.30 ± 0.68 mpa, 1.03 ± 0.24 mpa). However, UVA irradiation combined with riboflavin significantly increased the maximal stress and Young's modulus of corneal specimens with (5.27 ± 1.09 mpa, 1.23 ± 0.23 mpa, P < 0.05) or without (7.16 ± 1.88 mpa, 1.42 ± 0.16 mpa, P < 0.05) corneal epithelium when compared to the control group. The maximal stress and Young's modulus of cornea in UVA+riboflavin and "epithelium-off" group were 35.9% and 15.4% higher compared to the UVA+riboflavin and "epithelium-on" group, respectively (P < 0.05).


CONCLUSIONS
Our study shows that UVA+riboflavin treatment significantly affects the biomechanical properties of the cornea with and without epithelial removal. However, corneas without epithelium seem to benefit more compared to corneas with the epithelium.
Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China.
Xiangchen
X
Tao
Haiqun
H
Yu
Yong
Y
Zhang
Zhiwei
Z
Li
Vishal
V
Jhanji
Shouxiang
S
Ni
Ya
Y
Wang
Guoying
G
Mu
D000818:Animals; D003315:Cornea / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D019573:Epithelium, Corneal / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D005123:Eye / Q000187:drug effects* / Q000473:pathology; D011817:Rabbits; D012256:Riboflavin / Q000008:administration & dosage*; D014467:Ultraviolet Therapy
D012256:Riboflavin