Abstract
Purpose :
To study changes in gene expression after corneal cross-linking (CXL) in the rabbit cornea in vivo and to identify potential molecular signaling pathways.
Methods :
15 male New Zealand white rabbits (2.5 kg) were equally divided into 5 groups. All corneas were de-epithelialized using a hockey knife. Groups I to IV were soaked with 0.1%-riboflavin for 20 minutes, followed by UV-A irradiation at a fluence of 5.4 J/cm2, delivered at 3 mW/cm2 for 30 min (group I, standard CXL protocol), 9 mW/cm2 for 10 min (group II, accelerated), and 18 mW/cm2 for 5 min (group III, accelerated). Group IV served as riboflavin control, group V as virgin control. At one week after treatment, corneal buttons were obtained, mRNA was extracted and subjected to cDNA sequencing (RNA-seq).
Results :
CXL down-regulated enzyme activity (enolase 1, transketolase, cystatin, serine/threonine kinase) and extracellular matrix components (collagen types 1A1, 1A2, 6A2, 11A1, keratocan, fibromodulin). CXL activated pathways related to protein cross-linking (transglutaminase 2, osteonectin, cysteine-rich angiogenic inducer). Interestingly, CXL at 3mW/cm2 (Group 1) induced a more distinct change in gene expression than the accelerated CXL protocols, which induce less stiffening effect.
Conclusions :
Several target genes have been identified that might be related to the biomechanical stability of the cornea. The differential gene expression was dependent on the amount of biomechanical stiffening, suggesting the activation of mechano-sensitive pathways.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.