title: Safety assessment of oral photodynamic therapy in rats.
abstract: Photodynamic therapy (PDT) is based on the synergism of a photosensitive drug (a photosensitizer) and visible light to destroy target cells (e.g., malignant, premalignant, or bacterial cells). The aim of this study was to investigate the response of normal rat tongue mucosa to PDT following the topical application of hematoporphyrin derivative (Photogem®), Photodithazine®, methylene blue (MB), and poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with MB. One hundred and thirty three rats were randomly divided in various groups: the PDT groups were treated with the photosensitizers for 10 min followed by exposure to red light. Those in control groups received neither photosensitizer nor light, and they were subjected to light exposure alone or to photosensitizer alone. Fluorescent signals were obtained from tongue tissue immediately after the topical application of photosensitizers and 24 h following PDT. Histological changes were evaluated at baseline and at 1, 3, 7, and 15 days post-PDT treatment. Fluorescence was detected immediately after the application of the photosensitizers, but not 24 h following PDT. Histology revealed intact mucosa in all experimental groups at all evaluation time points. The results suggest that there is a therapeutic window where PDT with Photogem®, Photodithazine®, MB, and MB-loaded PLGA nanoparticles could safely target oral pathogenic bacteria without damaging normal oral tissue.
authors.affiliation: Department of Clinical Analysis, School of Pharmaceutical Sciences, University of São Paulo State (UNESP), 1621 Expedicionarios do Brasil Street, Araraquara, Sau Paulo, 14801-960, Brazil. fontanacr@fcfar.unesp.br
authors.forename: Carla R
authors.initials: CR
authors.lastname: Fontana
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lerman
authors.forename: Niraj
authors.initials: N
authors.lastname: Patel
authors.forename: Clovis
authors.initials: C
authors.lastname: Grecco
authors.forename: Carlos A de Souza
authors.initials: CA
authors.lastname: Costa
authors.forename: Mansoor M
authors.initials: MM
authors.lastname: Amiji
authors.forename: Vanderlei S
authors.initials: VS
authors.lastname: Bagnato
authors.forename: Nikolaos S
authors.initials: NS
authors.lastname: Soukos
mesh_terms: D000284:Administration, Oral; D000818:Animals; D005453:Fluorescence; D005944:Glucosamine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D017324:Hematoporphyrin Derivative / Q000008:administration & dosage / Q000494:pharmacology; D019344:Lactic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage / Q000627:therapeutic use; D009061:Mouth Mucosa / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D053758:Nanoparticles / Q000008:administration & dosage; D010778:Photochemotherapy / Q000009:adverse effects* / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D011100:Polyglycolic Acid / Q000008:administration & dosage / Q000494:pharmacology; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017208:Rats, Wistar
chemical_list: D017319:Photosensitizing Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; C047635:N-methylglucosamine; D019344:Lactic Acid; D017324:Hematoporphyrin Derivative; D005944:Glucosamine; D008751:Methylene Blue