Дегидротермический кросслинкинг стромальных графтов роговицы свиньи: влияние температуры на основные трансплантологические свойства. экспериментальное исследование

Abstract

Purpose. To evaluate the effect of DHT crosslinking of stromal corneal grafts at temperatures of 60, 100, 140, 180 and 220°C on their principal applicability in keratoplasty. Material and methods. A corneoscleral disc was excised from a porcine eye (< 12 h post-mortem) with epithelium and Descemet's membrane removed, dried, and a 10 mm central corneal graft was cut out. Dry grafts (n = 36) were divided into 6 groups of 6 samples: in five groups they were kept under vacuum for 3 days at 60, 100, 140, 180, 220 °C; 6th group – untreated control; then the grafts were immersed in phosphate-buffered saline for 24 h. Parameters evaluated: gross appearance, image quality from 5 m, light transmission, water content, central thickness, suture retention load. A test for epithelialization was performed ex vivo after 3 days in fresh porcine cornea organ culture. Results. The 220 °C mode caused charring destruction of the material. The grafts after 180 °C (10 g) became significantly weaker than the 10–0 nylon thread (90 g). In the range of 60–140 °C suture retention load significantly lowered from 913 g (control) down to 137 g (140 °C). Grafts increased their light transmission from 30 % (control) up to 75 % (140 °C); the central thickness went from 3000 (control) down to 320 um (140 °C), water content decreased from 94 % (control) down to 44 % (140 °C). Subjective image quality of the grafts after treatment at 60, 100, and 140 °C increased and grafts allowed distinguishing optotypes 0,3, 1,0 and 1,0 decimal, respectively. In organ culture control grafts and grafts after 60 and 100 °C treatment were covered with epithelial cells. 140 °C samples showed smooth surface with no cells upon. Сonclusion. Grafts after dehydrothermal treatment at temperatures 220 and 180 °C are principally not suitable for surgery. Grafts after 140 °C treatment do not pass epithelialization test. Grafts after 100 °C and lower can be used for keratoplasty. Keywords: crosslinking, corneal surgery, grafts, epithelial cells