Photodynamic therapy mediated by methylene blue dye in wound healing.
OBJECTIVE
We sought to investigate the wound-healing process after photodynamic therapy (PDT) mediated by methylene blue dye (MB).


BACKGROUND
Few scientific studies show the PDT roles in wound healing.


METHODS
One hundred rats were given a circular wound on the back, inflicted with a 6-mm-diameter punch. The animals were divided into four groups: control (no treatment); dye (topical application of MB); laser (InGaAlP, 117.85 J/cm(2), 100 mW, 660 nm, single point); and PDT (topical application of MB followed by laser irradiation). After 1, 3, 5, 7, and 14 days, the cutaneous wounds were photographed and assessed with histopathologic examination by using light microscope. Changes seen in edema, necrosis, inflammation, granulation tissue, re-epithelialization, and number of young fibroblasts were semiquantitatively evaluated. The wound-area changes were measured with special software and submitted to statistical analysis.


RESULTS
The laser group demonstrated the smallest wound area at 14 days after the surgical procedure (p < 0.01). Concerning complete re-epithelialization, the laser group showed it at 5-7 days after surgery, whereas the PDT and the other groups showed it at 14 days.


CONCLUSIONS
Laser interaction with tissue is somehow changed when exposed to the MB. PDT mediated by MB was not prejudicial to wound healing, as no delay occurred compared with the control group.
Department of Oral Pathology, School of Dentistry, University of São Paulo, Brazil. sperandio@usp.br
Felipe Fornias
FF
Sperandio
Alyne
A
Simões
Ana Cecília Corrêa
AC
Aranha
Luciana
L
Corrêa
Suzana C
SC
Orsini Machado de Sousa
D000818:Animals; D001707:Biopsy, Needle; D004396:Coloring Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy / Q000379:methods; D008751:Methylene Blue / Q000494:pharmacology*; D010778:Photochemotherapy / Q000379:methods*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D014945:Wound Healing / Q000187:drug effects*; D014947:Wounds and Injuries / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy
D004396:Coloring Agents; D008751:Methylene Blue