title: Polypodium leucotomos inhibits ultraviolet B radiation-induced immunosuppression.
abstract: BACKGROUND
  An extract of the tropical fern Polypodium leucotomos (PL) administered orally to mice inhibits ultraviolet B (UVB) radiation-induced skin cancer formation. UVB-induced murine skin cancers occur, in part, because of UVB-induced immunosuppression. Thus, we examined whether PL inhibits UVB-suppression of the induction of contact hypersensitivity (CHS) locally or systemically.
  
  
  METHODS
  C57BL/6 mice received standard drinking water or water-containing PL. In the local model, mice were shaved on the dorsum and exposed to 3500 J/m(2) of UVB radiation daily for 4 days. Control mice were not irradiated. After the last irradiation they were sensitized to oxazolone topically at the irradiated site. To examine the ability of PL to inhibit systemic UVB-induced immunosuppression, mice were given 10,000 J/m(2) of UVB radiation once and immunized at a non-exposed site 3 days later. Six days after immunization (in both models), mice were challenged on the ears with oxazolone and 24/48 h ear swelling assessed.
  
  
  RESULTS
  PL in drinking water significantly reduced the inhibition of CHS observed with exposure to UVB radiation in both the local and systemic models.
  
  
  CONCLUSIONS
  The ability of PL to inhibit UVB radiation-induced immune suppression may explain, in part, its ability to inhibit UVR-induced skin cancer induction in mice.
authors.affiliation: Department of Dermatology, Weill Cornell Medical College, New York, NY 10021, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Siscovick
authors.forename: Tamar
authors.initials: T
authors.lastname: Zapolanski
authors.forename: Cynthia
authors.initials: C
authors.lastname: Magro
authors.forename: Kristel
authors.initials: K
authors.lastname: Carrington
authors.forename: Shannon
authors.initials: S
authors.lastname: Prograis
authors.forename: Marnie
authors.initials: M
authors.lastname: Nussbaum
authors.forename: Salvador
authors.initials: S
authors.lastname: Gonzalez
authors.forename: Wanhong
authors.initials: W
authors.lastname: Ding
authors.forename: Richard D
authors.initials: RD
authors.lastname: Granstein
mesh_terms: D000818:Animals; D017449:Dermatitis, Allergic Contact / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D004423:Ear / Q000473:pathology; D007108:Immune Tolerance / Q000187:drug effects* / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D010081:Oxazolone / Q000008:administration & dosage / Q000009:adverse effects; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D032494:Polypodium; D011829:Radiation Dosage; D012867:Skin / Q000276:immunology / Q000473:pathology; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D010936:Plant Extracts; D010081:Oxazolone