title: Long-term effects of local ionizing radiation treatment on Langerhans cells in mouse footpad epidermis.
abstract: Langerhans cells (LC) were studied with ADPase histochemistry in sheets of hind footpad epidermis from groups of CBA/H mice. Single, local 20-Gy doses of 250-kV x-rays were administered to the right hind feet of the mice when they were 3-4 months old, and LC were counted at intervals ranging from 2 to 24 months later. In unirradiated mice, aged 5-19 months, the mean density of LC in footpad was 1521-1617 cells/mm2. It dropped to 1137 +/- 86 cells/mm2 (mean +/- SE) in untreated 28-month-old mice. At times from 2-15 months after irradiation, normal mean densities of LC were present in footpad epidermis. On average, LC numbers were subsequently reduced to 1078 +/- 65/mm2 by 19 months after irradiation (71% of the cells in age-matched controls) and to 789 +/- 53/mm2 by 24 months (59% of the cells in age-matched controls). Loss of cells was focal. Chronic radiation-induced fibrosis and damage to circulatory function in skin may have contributed to impaired replacement of LC from bone marrow precursors. The possibility that late radiation-related depletion of the LC population permits development of skin tumors as a delayed consequence of exposure to ionizing radiation is discussed.
mesh_terms: D000367:Age Factors; D000818:Animals; D001081:Apyrase / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004817:Epidermis / Q000528:radiation effects*; D005260:Female; D005528:Foot; D007801:Langerhans Cells / Q000201:enzymology / Q000528:radiation effects*; D051379:Mice; D008808:Mice, Inbred CBA; D012880:Skin Pigmentation / Q000528:radiation effects; D013997:Time Factors; D014965:X-Rays
chemical_list: D001081:Apyrase