title: Phototoxic action of light emitting diode in the in vitro viability of Trichophyton rubrum.
abstract: BACKGROUND
  Trichophyton rubrum is the most common agent of superficial mycosis of the skin and nails causing long lasting infections and high recurrence rates. Current treatment drawbacks involve topical medications not being able to reach the nail bed at therapeutic concentrations, systemic antifungal drugs failing to eradicate the fungus before the nails are renewed, severe side effects and selection of resistant fungal isolates. Photodynamic therapy (PDT) has been a promising alternative to conventional treatments.
  
  
  OBJECTIVE
  This study evaluated the in vitro effectiveness of toluidine blue O (TBO) irradiated by Light emitting diode (LED) in the reduction of T. rubrum viability.
  
  
  METHODS
  The fungal inoculums' was prepared and exposed to different TBO concentrations and energy densities of Light emitting diode for evaluate the T. rubrum sensibility to PDT and production effect fungicidal after photodynamic treatment. In addition, the profiles of the area and volume of the irradiated fungal suspensions were also investigated.
  
  
  RESULTS
  A small reduction, in vitro, of fungal cells was observed after exposition to 100 µM toluidine blue O irradiated by 18 J/cm² Light emitting diode. Fungicidal effect occurred after 25 µM toluidine blue O irradiation by Light emitting diode with energy density of 72 J/cm². The analysis showed that the area and volume irradiated by the Light emitting diode were 52.2 mm² and 413.70 mm³, respectively.
  
  
  CONCLUSIONS
  The results allowed to conclude that Photodynamic therapy using Light emitting diode under these experimental conditions is a possible alternative approach to inhibit in vitro T. rubrum and may be a promising new treatment for dermatophytosis caused by this fungus.
authors.affiliation: Universidade de Itaúna, Itaúna, MG, Brazil.
authors.forename: José Cláudio Faria
authors.initials: JC
authors.lastname: Amorim
authors.forename: Betania Maria
authors.initials: BM
authors.lastname: Soares
authors.forename: Orley Araújo
authors.initials: OA
authors.lastname: Alves
authors.forename: Marcus Vinícius Lucas
authors.initials: MV
authors.lastname: Ferreira
authors.forename: Gerdal Roberto
authors.initials: GR
authors.lastname: Sousa
authors.forename: Lívio de Barros
authors.initials: Lde B
authors.lastname: Silveira
authors.forename: André Costa Cruz
authors.initials: AC
authors.lastname: Piancastelli
authors.forename: Marcos
authors.initials: M
authors.lastname: Pinotti
mesh_terms: D004307:Dose-Response Relationship, Radiation; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D014048:Tolonium Chloride / Q000627:therapeutic use*; D014249:Trichophyton / Q000528:radiation effects*
chemical_list: D017319:Photosensitizing Agents; D014048:Tolonium Chloride