Photodynamic therapy for pythiosis

Autor(es)

Pires, Layla ^[1] ; Bosco, Sandra de M. G. ^[2] ; da Silva Junior, Nelson F. ^[3] ; Kurachi, Cristina ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, Phys Inst Sao Carlos, Dept Microbiol & Imunol, BR-18618970 Botucatu, SP - Brazil

^[2] Univ Estadual Paulista, Inst Biociencias Botucatu, Dept Microbiol & Imunol, BR-18618970 Botucatu, SP - Brazil

^[3] Univ Sao Paulo, Escola Engn Sao Carlos, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: VETERINARY DERMATOLOGY; v. 24, n. 1, p. 130+, FEB 2013.
• Citações Web of Science: 4

Resumo

Background Pythiosis is a life-threatening disease caused by Pythium insidiosum. Photodynamic therapy (PDT) is an alternative treatment to surgery that uses the interaction of a photosensitizer, light and molecular oxygen to cause cell death. Objectives To evaluate the effect of PDT on the in vitro growth of P.insidiosum and in an in vivo model of pythiosis. Methods For in vitro studies, two photosensitizers were evaluated: a haematoporphyrin derivative (Photogem (R)) and a chlorine (Photodithazine (R)). Amphotericin B was also evaluated, and the control group was treated with sterile saline solution. All experiments (PDT, porphyrin, chlorine and light alone, amphotericin B and saline solution) were performed as five replicates. For in vivo studies, six rabbits were inoculated with 20,000 zoospores of P.insidiosum, and an area of 1 cm3 was treated using the same sensitizers. The PDT irradiation was performed using a laser emitting at 660 nm and a fluence of 200 J/cm2. Rabbits were clinically evaluated daily and histopathological analysis was performed 72 h after PDT. Results For in vitro assays, inhibition rates for PDT ranged from 60 to 100% and showed better results in comparison to amphotericin B. For the in vivo assays, after PDT, histological analysis of lesions showed a lack of infection up to 1 cm in depth. Conclusions and clinical importance In vitro and in vivo studies showed that PDT was effective in the inactivation of P.insidiosum and may represent a new approach to treating pythiosis. (AU)

• Processo FAPESP: 08/03511-8 - Avaliação do Efeito Fotodinâmico sobre o Crescimento in vitro de Pythium insidiosum
• Beneficiário: Layla Pires
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica