Structural and ultrastructural features of early skin damage after local high-dose radiation exposure

Introduction. Research on skin radiation injury remains topical due to the development of X-ray diagnosis and therapy in medical practice. Materials and methods. We studied structural and ultrastructural features of high-dose ionizing radiation exposure to the skin (110 Gy, X-ray) at early stages of damage (days 3, 8, and 14). The study was conducted on Wistar rats (N=39) that were exposed to a single irradiation on the interscapular skin region with an LNK–268 (RAP 100–10) X-ray machine (Russia). To analyze the morphologic changes, light (hematoxylin and eosin stain and toluidine blue stain) and transmission electron microscopy were used. Results. Regardless of clinical manifestations on day 3, subepidermal edema, intercellular edema and epithe-lial layer contact disruption, mitochondria damage to the keratinocytes, and dermal histiocytes developed in the area of radiation exposure. These signs intensified by days 8 and 14, leading to tissue death both at the central and peripheral parts of irradiation. On days 8–14, damage to the vascular endothelial cells became noticeable, the mitochondrial death being the major one. Morphometric data indicate an increase both in the epidermis edema up to its desquamation by day 14 and in total cellularity due to various forms of leukocytes in the papillary and reticular dermis. Conclusion. Local 110-Gy irradiation leads to irreversible changes in the cells and their necrosis within two weeks that may result in ulcer formation later in life. Keywords: radiation ulcer, damage, skin, cell death, ultrastructure