Purpose: The aim of this investigation was to describe the alterations in oral mucosa after radiotherapy.
Methods and materials: Biopsies were taken from patients before irradiation, at 60 Gy, and 6-12 months after radiotherapy. Histomorphological evaluation of the vessels was performed, and endothelial expression of ICAM-1, VCAM-1, and E-selectin was also evaluated, as well as distribution of LFA-1-, Mac-1-, VLA-4-, RM3/1-, 27E10-, and 25F9-bearing cells in the subepithelial tissue.
Results: The expression of ICAM-1 was downregulated after radiotherapy, whereas the percentage of LFA-1- and VLA-4-bearing cells increased. VCAM-1 remained at low levels. The subepithelial infiltration was still dominated by RM3/1-positive macrophages. The number of vessels decreased, while the lumina of the remaining vessels in the deeper connective layer increased.
Conclusions: The late effects of radiotherapy are characterized by a decreased number of blood vessels and by significantly different expression patterns of the adhesion molecules studied, and of integrins and macrophage subpopulations compared to the conditions before irradiation and at 60 Gy.