Radiobiology of the Skin: Review of Some Effects on Epidermis and Hair

Abstract

Significant doses of ionizing radiation produce an acute skin reaction characterized by erythema, epilation, and dry or moist desquamation with or without erosions. These early acute changes are dose-dependent and reflect damage to the germinative cells of the epidermis and to the cutaneous vasculature. Studies in the pig, for example, have shown that the degenerative phase of cell loss (2-3 weeks) results from reproductive failure in germinative cells and a sharp reduction in the proliferation rate of basal cell "survivors." D0 values for epidermal cells in different species generally range from 100-140 rads. Cell maturation and ascension rates in the suprabasilar layers are largely unaffected. A regenerative phase of cell replacement, characterized by sharply increased cell replication rates, occurs from the 3rd to 5th postradiation weeks. The postregenerative phase of hyperplasia reflects a temporary overshoot of cell density above control levels; a subsequent decrease in hyperplasia indicates feedback control of cellular proliferation. Postradiation changes in the highly proliferative anagen hair matrix cell populations result in hair dysplasia, slowed growth rates, impaired metabolic processes, and alopecia. Dosages of 700-800 rads or more induce some degree of permanent hair loss. G0 telogen matrix cells are 2-3 times more radioresistant than proliferating anagen matrix cells, but may "store" radiation damage for prolonged periods. Altered matrix cell uptake of amino acids, the incidence of dysplasia, and the degree of alopecia occurring after irradiation have all been used as quantitative biological end-points for the general study of cellular radiation effects, as well as studies on the enhancement of or protection against radiation damage provided by certain pharmacologic or physical agents.

Radiation dermatitis: Clinical presentation, pathophysiology, and treatment 2006

“…Mitotic activity in the germinal cells of the sebaceous glands, hair follicles, and epidermis is inhibited, and basal layer stem cells are depleted. 9,19,29,41 Prostaglandins and thiol compounds are potentially radioprotective agents that have been used to protect normal tissue, with varying degrees of success. In animal models, both have been used to protect hair follicles and other skin structures.…”

Biodosimetric quantification of short-term synchrotron microbeam versus broad-beam radiation damage to mouse skin using a dermatopathological scoring system

“…Zhong et al [7] stated that the \integrated microbeam doses, (which for low valley doses) can be approximated as the in-beam dose times the ratio of the beam width to beam spacing". There exists a vast body of literature over several decades on the acute effects of radiation therapy on skin tissue (radiodermatitis), some of which have been documented in review articles [14,15] and text books [16][17][18][19]. McKee et al [20] state:…”

Comparative Study Between Topical Applications of Liposomally Entrapped Dna Repair Enzymes and Thymidine Dinucleotides as Radioprotectors

“…Moreover, large number of langerhans cells was present in irradiated rat skin and disappeared with topical treatment. Studies in the pig skin, showed that postregenerative phase of hyperplasia reflect a temporary overshoot of cell density above control levels; a subsequent decrease in hyperplasia indicates feedback control of cellular proliferation 14 . Collagen is known to constitute 70% of dry skin mass, which is either collagen type I, III and VI.…”