Treatment of oral candidiasis with methylene blue-mediated photodynamic therapy in an immunodeficient murine model

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002 Feb;93(2):155-60. doi: 10.1067/moe.2002.120051.


Objectives: The purpose of this study was to evaluate the efficacy of using methylene blue (MB)-mediated photodynamic therapy to treat oral candidiasis in an immunosuppressed murine model, mimicking what is found in human patients.

Study design: Seventy-five experimental mice with severe combined immunodeficiency disease were inoculated orally with Candida albicans by swab 3 times a week for a 4-week period. On treatment day, mice were cultured for baseline fungal growth and received a topical oral cavity administration of 0.05 mL MB solution at one of the following concentrations: 250, 275, 300, 350, 400, 450, or 500 microgram/mL. After 10 minutes the mice were recultured and underwent light activation with 664 nm of diode laser light with a cylindrical diffuser. After photodynamic therapy the mice were cultured again for colony-forming units per milliliter and then killed, their tissue harvested for histopathology.

Results and conclusions: The results indicate an MB dose-dependent effect. Concentrations from 250 to 400 microgram/mL reduced fungal growth but did not eliminate Candida albicans. MB concentrations of 450 and 500 microgram/mL totally eradicated Candida albicans from the oral cavity, resulting in reductions from 2.5 log(10) and 2.74 log(10) to 0, respectively. These results suggest that MB-mediated photodynamic therapy can potentially be used to treat oral candidiasis in immunodeficient patients.

Publication types

  • Evaluation Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antifungal Agents / pharmacology
  • Azoles / pharmacology
  • Candida albicans / drug effects
  • Candidiasis, Oral / drug therapy*
  • Candidiasis, Oral / microbiology
  • Colony Count, Microbial
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Drug Resistance, Fungal
  • Methylene Blue / administration & dosage*
  • Methylene Blue / therapeutic use
  • Mice
  • Mice, Nude
  • Mice, SCID
  • Photochemotherapy / methods*
  • Photosensitizing Agents / administration & dosage*
  • Photosensitizing Agents / therapeutic use


  • Antifungal Agents
  • Azoles
  • Photosensitizing Agents
  • Methylene Blue