Dermal dysplasia, hypotrichosis, and dorsal skin ulcers in adult NMRI-mice after X-irradiation in utero.

Prenatal X-irradiation in mice leads to a marked incidence of hypotrichosis and alopecia in offspring, when irradiation occurs during the stage of late organogenesis (day 11-13 p.c.). In addition, severe ulcerative dermatitis occurs in offspring starting at 2 months of age, with marked preference for those animals, which have been irradiated at least during days 11-13 p.c. This occurs without any dose dependence; application of doses between 2.4 Gy and 7.2 Gy results in approximately similar incidence rates of skin ulcers (range between 39.1 and 48.0%). There is no sex preference and no dependence on housing. At autopsy no special abnormalities were found in the internal organs with the exception of frequent signs of amyloidosis. This disease pattern could also be produced in germ-free animals. The intracutanous administration of skin extracts from affected animals into unirradiated mice leads to a marked infiltration of leukocytes. It is therefore suggested that prenatal X-irradiation induces a distinct dysplasia of the epidermis, which is followed by an endogenous leukotactic activity.