Abstract
Purpose:
To evaluate whether different UV-A treatment intensities on human corneas (ex vivo) soaked through iontophoresis procedure performed with a new hypotonic solution of riboflavin + enhancer, determine different morphological and biochemical response on the corneal tissue (epithelium, keratocytes, collagen and nerve fibers and endothelium).
Methods:
Fifteen human cadaver corneas were divided in 3 different groups according to methods of soaking and UV-A intensity used: Group 1- four corneas, treated with the new riboflavin formulation using iontophoresis for 5 minutes and an irradiance power of 3 mW/cm2 for 30 minutes; Group 2 - four corneas treated with the new riboflavin formulation using iontophoresis for 5 minutes and an irradiance power of 10 mW/cm2 for 9 minutes; Group 3 - four corneas treated with the new riboflavin formulation using iontophoresis for 5 minutes without irradiance power; Group 4 - three untreated corneas utilized as control. All samples were prepared for immunohistochemical and biomolecular analysis using different markers as β catenin, connexin 43, CD34, vimentin/desmin and collagen I.
Results:
Group 3 didn’t show corneal modifications and the appearance was similar to the control corneas. The crosslinking groups (Group 1 and Group 2) showed variable changes in the stroma, mainly due to keratocytes apoptosis and in relationship with the intensity of the treatment. No corneas showed signs of fibrosis with a negative Desmin-Vimentin staining. No endothelial damage was evidenced in the treated groups, nor nerve fiber alterations.
Conclusions:
On the basis of this ex-vivo study, iontophoresis can be considered a potential delivery tool for riboflavin penetration in the corneal stroma. Variable morphological changes are related to different intensity of energy.
Keywords: 479 cornea: clinical science