title: Protective effects of Polypodium leucotomos extract against UVB-induced damage in a model of reconstructed human epidermis.
abstract: BACKGROUND
  Polypodium leucotomos (PL) exerts potent antioxidant, photo-protective, and immune-modulatory activities. A reconstructed human epidermis (RHE) (Episkin) is a suitable model for the evaluation of acute UV-induced cell damage. No data regarding the photo-protective action of PL in this model are available.
  
  
  OBJECTIVE
  We evaluated the effects of PL on the prevention of UVB-induced cell damage assessing sunburn cells, CPD formation, p53, Ki-67, p21 expression, and epidermal growth factor (EGF) production.
  
  
  METHODS
  RHE was incubated in standard conditions. PL was topically applied at the concentration of 2 mg/cm2, immediately before UVB exposition. UVB exposition (300 mJ/cm2) was performed using a dedicated UVB lamp. Irradiated samples without PL and non-irradiated samples were used as positive and negative controls. Expression of p53, p21, and Ki-67 was evaluated with immune-histochemical methods. CPD were measured using a monoclonal antibody.
  
  
  RESULTS
  PL significantly reduced sunburned cells (-80%) in comparison with positive control. PL significantly prevented the increase in EGF production at tested times. PL significantly reduced the p53 (-80%), p21 (-84%), and Ki-67 (-48%) positive cells. Finally, PL prevented the formation of CPD (0% vs. 20% positive cells).
  
  
  CONCLUSIONS
  In this model, PL has shown to prevent UVB cell damage, the upregulation of proliferating proteins, and fully blocking the formation of CPD.
authors.affiliation: Laboratory of Biocompatibility Innovative Technologies and Advanced Therapies (BITTA), Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Torricelli
authors.affiliation: Laboratory of Biocompatibility Innovative Technologies and Advanced Therapies (BITTA), Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.affiliation: Dermatology Clinic of the University of Bologna, Bologna, Italy.
authors.forename: Pier Alessandro
authors.initials: PA
authors.lastname: Fanti
authors.affiliation: Dermatology Clinic of the University of Bologna, Bologna, Italy.
authors.forename: Emi
authors.initials: E
authors.lastname: Dika
authors.affiliation: Medical Direction Difa Cooper, Caronno Pertusella, Italy.
authors.forename: Massimo
authors.identifier: http://orcid.org/0000-0001-7559-1202
authors.initials: M
authors.lastname: Milani
mesh_terms: D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000096:biosynthesis; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008954:Models, Biological; D010936:Plant Extracts / Q000494:pharmacology*; D032494:Polypodium; D011740:Pyrimidine Dimers / Q000378:metabolism; D013471:Sunburn / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D019394:Ki-67 Antigen; D010936:Plant Extracts; D011740:Pyrimidine Dimers; D016159:Tumor Suppressor Protein p53; D004815:Epidermal Growth Factor
keywords: Polypodium leucotomos; photoprotection; ultraviolet skin damage