title: Polydeoxyribonucleotide promotes cyclobutane pyrimidine dimer repair in UVB-exposed dermal fibroblasts.
abstract: BACKGROUND
  DNA is the main cellular chromophore for ultraviolet B (UVB). Its absorption leads to the generation of typical photoproducts. The most frequent types (about 80%) are cyclobutane pyrimidine dimers (CPDs). Several studies have suggested that treatment with deoxyribonucleosides can protect some cell types from DNA damage. The aim of this work was to evaluate the ability of the polydeoxyribonucleotide (PDRN) to protect human dermal fibroblasts from UVB-induced DNA damage.
  
  
  METHODS
  Human dermal fibroblasts were irradiated with 600 mJ/cm(2) of UVB radiation. Cells were analyzed at increasing time points from irradiation to study the recovery from UVB-induced DNA photodamage. Damage repair was subsequently assessed by immunocytochemical analysis of CPDs levels and by measurement of p53 protein expression.
  
  
  RESULTS
  The extracellular addition of 100 microg/ml PDRN immediately after irradiation caused a strong activation of p53 protein in the first 24 h. This signal was accompanied by an increase in CPDs repair rates at early time points of recovery.
  
  
  CONCLUSIONS
  The addition of PDRN to the culture medium supports CPDs repair probably providing a faster supply of precursors for the deoxyribonucleotide triphosphates pool necessary to UVB-damaged cells. This condition could promote the action of the salvage pathway, thereby accelerating DNA repair, but other inducible responses linked to increased p53 expression could be involved.
authors.affiliation: Department of Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Belletti
authors.forename: Jacopo
authors.initials: J
authors.lastname: Uggeri
authors.forename: Rita
authors.initials: R
authors.lastname: Gatti
authors.forename: Paolo
authors.initials: P
authors.lastname: Govoni
authors.forename: Stefano
authors.initials: S
authors.lastname: Guizzardi
mesh_terms: D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism* / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D011089:Polydeoxyribonucleotides / Q000378:metabolism / Q000494:pharmacology*; D011740:Pyrimidine Dimers / Q000378:metabolism* / Q000528:radiation effects*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D011089:Polydeoxyribonucleotides; D011740:Pyrimidine Dimers; D016159:Tumor Suppressor Protein p53; D004247:DNA