title: Short-term exposure to UV-A, UV-B, and UV-C irradiation induces alteration in cytoskeleton and autophagy in human keratinocytes.
abstract: Ultraviolet radiation (UV) induces a series of morphological and ultrastructural alterations in human epidermis. Alterations observed in irradiated keratinocytes in morphological studies done before were cell retraction with loss of intercellular interactions, surface blebbing, and eventually cell death by apoptosis. The aim of this study was to investigate effect of UV-A, UV-B, and UV-C irradiation on the cytoskeleton of human keratinocytes. Keratinocytes were obtained by exfoliative scrubbing procedure from buccal mucosa of healthy individuals, and treated with UV-A, UV-B, and UV-C radiation. Afterward, treated cell were labeled with anti-alfa-tubulin and anti-human-cytokeratin and analyzed by light and confocal microscopy. The intensity of the cytokeratin labeling was found to be much higher in all irradiated cells than in control cells as observed by light microscope and measured with the Image J program. This measurement showed that with the decrease in the wavelengths of UV irradiation the intensity of the labeling of cells increases. Although the authors expected to find the collapse of microtubules toward the cell nucleus or their rearrangement in UV-treated cells, these alterations were not verified on cell smears labeled with anti-alfa tubulin observed by confocal microscope. When they used electron microscopy to examine in more detail the morphology of irradiated cells, they did not find apoptotic cells, but found features of autophagy in UV-treated keratinocytes. The authors assume that autophagy found as a result of UV radiation of human keratinocytes acts as a cytoprotective mechanism against UV-induced apoptosis.
authors.affiliation: Institute of Histology and Embryology, Medical Faculty Belgrade, University of Belgrade, Belgrade, Serbia.
authors.forename: Milan
authors.initials: M
authors.lastname: Misovic
authors.forename: Dusan
authors.initials: D
authors.lastname: Milenkovic
authors.forename: Tamara
authors.initials: T
authors.lastname: Martinovic
authors.forename: Darko
authors.initials: D
authors.lastname: Ciric
authors.forename: Vladimir
authors.initials: V
authors.lastname: Bumbasirevic
authors.forename: Tamara
authors.initials: T
authors.lastname: Kravic-Stevovic
mesh_terms: D000328:Adult; D001343:Autophagy / Q000528:radiation effects*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000528:radiation effects* / Q000648:ultrastructure*; D008297:Male; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult