原著

著者

Katsuaki TAIRA, Akiyosi SAITO, Toru YAMAMOTO, Takanori IRIUCHISHIMA,
Shin AIZAWA*, Masataka NAKAZATO** and Junnosuke RYU
Department of Orthopaedic Surgery, Nihon University School of Medicine
*Department of Anatomy, Nihon University School of Medicine
**Chlorophyll Reserch Institute Co., Ltd

要旨

Photodynamic therapy (PDT) has been established as a novel treatment method for methicillin-resistant Staphylococcusaureus (MRSA) infection. To elucidate the efficacy of combined use of a semiconductor laser with thephotosensitizer Na-pheophorbide a (Na-Phde a), in vivo bactericidal studies were carried out using a murinemodel of MRSA arthritis. Three experimental groups were used; 1) treatment with a combination of intra-articularinjection of Na-Phde a and percutaneous laser irradiation (PDT group), 2) treatment with only intra-articular injectionof Na-Phde a, (Na-Phde a group), and 3) treatment with laser irradiation and intra-articular injection of physiologicalsaline (laser group). The control group received intra-articular injection of physiological saline withoutlaser irradiation. Bactericidal effects were assessed at 3 days after MRSA injection by bacterial culture of synovialfluid, and histopathological examination of the joints. The results among the groups were compared in order toevaluate the therapeutic efficacy of PDT with Na-Phde a and laser irradiation for MRSA arthritis. Bacterial culturestudies revealed the presence of bacteria in 1 of 10 joints after treatment with PDT, thus demonstrating the bactericidaleffects of PDT. Conversely, bacterial growth was detected in the Na-Phde a, laser and control groups. Histopathologicalstudy revealed slight neutrophil extravasation but no remarkable changes in the cartilage of the PDTgroup, thus confirming the therapeutic efficacy of PDT. The other groups exhibited neutrophil infiltration anddestruction of cartilage. These in vivo experimental results indicate that PDT with a combination of Na-Phde a andpercutaneous laser irradiation is a useful treatment for MRSA arthritis.

keyword

Photodynamic Therapy (PDT), Na-Pheophorbide a (Na-Phde a), Model of MRSA arthritis, diode
laser