Resumen de Immediate histological and biomechanical changes in human corneal tissue after riboflavin-UVA collagen cross-linking
María Ángeles del Buey Sayas, Elena Lanchares, José Angel Cristóbal Bescós, Santiago Ramón y Cajal Junquera, Carmen Yus Gotor, Begoña Calvo Calzada
PURPOSE: To study the immediate biomechanical and histological effects of riboflavin/ultraviolet A (UVA) irradiation-induced collagen cross-linking (CXL) on healthy human corneal tissue.
SETTING: Laboratory study. Collaborative effort of two hospitals and several departments and research centres related to the University of Zaragoza.
METHODS: Mechanical tensile tests and histological analysis were performed ex vivo in deepithelialized healthy human corneal tissue treated with riboflavin solution (0.01% riboflavin- 5-phosphate and 20% dextran T-500) followed by 30 minutes UVA irradiation. A similar study was completed on untreated de-epithelialized healthy human corneal tissue. Both histological and mechanical analyses were performed immediately after treatment. Corneal biomechanical properties were compared by measuring the stress-strain behaviour of the two specimens, using stress data at 6%, 8%, 10% and 12% stretch.
RESULTS: Analysis of the stress-strain curves showed a different corneal response between the treated and untreated samples. The treated corneal tissue was 1.8, 1.6, 1.7 and 1.5-fold stiffer than the untreated sample at 6%, 8%, 10% and 12% stretch, respectively. Histological analysis of the cross-linked sample showed compaction of the tissue, and interlamellar spaces appeared to be smaller compared to the control sample. Keratocyte destruction was observed in the treated tissue even at deep stromal level.
CONCLUSIONS: UVA-induced collagen cross-linking has an immediate biomechanical and histological effect on treated healthy human corneal tissue. Stiffening of the tissue, keratocyte destruction and stromal compacting were observed.
