Analisi morfologica degli effetti di radiazioni ionizzanti su epidermide umana in un modello anatomico di colture organotipiche

Skin is a target organ for crucial side-effects of radiotherapy and the early effects on epidermis remain to be fully elucidated. Organotypic cultures of human skin can help in defining the early effects difficult to study in humans. To characterize our model, we performed a keratinocyte proliferation analysis in a time course study and then in irradiated samples. We evaluated the effects on terminal differentiation, intercellular adhesion and apoptosis by immunofluorescence and ultrastructural analysis. Bioptic fragments (n=8) were obtained from cosmetic surgery of young healthy women, cultured in Transwell, and harvested 24 or 48 hours after exposure to a single 2 Gy dose of gamma-rays. Epidermal proliferation progressively decreased in the time course study and significantly inhibited 24 hrs after gamma-rays. Patterns of CK10, INV, Dsg1 and Dsc1 proteins distribution were comparable in all samples. P53 was similarly detected in scattered positive keratinocytes in the spinous layer of 24 hrs samples, whilst in 48 hrs irradiated samples was expressed starting from basal layer. TEM analysis indicated that no desmosomal ultrastructural modifications occurred. In 24hrs irradiated skin the basal layer was undamaged but a condensation of intermediate filaments and apoptosis were evident in the upper spinous layers. In 48hrs irradiated skin apoptotic nuclei started from the basal layer. The epidermal homeostasis is rapidly altered by a single clinical dose of gamma-rays.