Morphological assessment of changes in the cornea of experimental animals after ultraviolet corneal cross-linking

Purpose. To investigate the dynamics of morphological changes in the rat cornea after its ultraviolet cross-linking using various photosensitizer solutions. Material and methods. Studies were conducted on 20 rats in three groups. In the first group, 0.1% Riboflavin solution was used for saturation, in the second – 0.1% Riboflavin and 20% dextran; the third – intact (control). A UV cross-linking model (370 nm, 3 mW/cm2, 10 min) with corneal deepithelization with a diameter of 3 mm was used. Histomaterial processing was performed according to the standard procedure on the 3rd, 7th, and 30th days after surgery. Histological sections 1-4 microns thick were prepared on a rotary microtome RM 2145 (Leica Microsystems, Germany), stained with hematoxylin-eosin and using the van Gieson method. Light microscopy was performed using a LEICA DM 2500 microscope with a Leica DFC 450 digital camera (Leica Microsystems, Germany). Results. The main morphological changes in the rat cornea after UV cross-linking with 0.1% Riboflavin solution were associated with loosening of bundles of collagen fibers. This was caused by the development of stroma edema in the early postoperative period (3-7 days), which persisted up to 30 days of the experiment. A morphological feature of the use of Dextralink solution in corneal cross-linking is less pronounced stroma disfoliation, which is associated with the dehydrating effect of dextran. In both groups, a decrease in the density of stroma keratocytes was found. Key words: cornea, ultraviolet corneal cross-linking, corneal morphology.