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The minimum influences for murine normal joint tissue by novel bactericidal treatment and photodynamic therapy using
Takanori Iriuchishima1, Akiyoshi Saito, Shin Aizawa
1Department of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan. sekaiwoseisu@yahoo.co.jp
Objective:
In this study, we examined the effect of photodynamic therapy (PDT) using Na-pheophorbide a (Na-Phde a) on normal joint tissue.
Background Data:
The treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection is a serious issue. Recently, an experimental in vivo and in vitro model for the inactivation of MRSA by PDT using a photosensitizer, Na-Phde a, has been developed.
Materials And Methods:
The knee joints of mice were injected with 560 or 280 micromol/L of Na-Phde a. Thirty minutes after injection, percutaneous laser irradiation was applied for 5 min using a semiconductor laser (power: 125 mW; wavelength: 664 nm; total energy: 12 J/cm2). The joint perimeter and body weight of the treated mice were monitored, and histological evaluation was also done.
Results:
Joint swelling was observed up to 3 wk after PDT (p < 0.05). On histology 1 wk post-PDT, the treated knees were found to have inflammatory changes, primarily in synovial tissue. Eight weeks after PDT, the synovitis was no longer present. No significant effects were observed on cartilage, bone marrow, or menisci.
Conclusions:
The results of this experiment showed that PDT with Na-Phde a induced arthritis for a short time after treatment. However, this arthritis was reversible, and the PDT did not appear to induce osteoarthritic changes in normal joint tissue. These findings indicate that PDT using Na-Phde a caused minimal but reversible changes in joint tissue, suggesting that it would be a safe and useful treatment for bacterial septic arthritis.
Insights
Photodynamic therapy (PDT) with Na-pheophorbide a (Na-Phde a) caused temporary, reversible joint inflammation in mice. This safe and effective treatment showed no long-term damage to normal joint tissues.
Area of Science:
- Biomedical research
- Photochemistry
- Orthopedics
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) infections pose a significant clinical challenge.
- Photodynamic therapy (PDT) is being explored as a novel treatment modality.
- A photosensitizer, Na-pheophorbide a (Na-Phde a), has shown promise for MRSA inactivation in experimental models.
Purpose of the Study:
- To evaluate the effects of Na-Phde a-mediated photodynamic therapy (PDT) on normal joint tissues.
- To assess the safety and potential side effects of PDT in a preclinical setting.
Main Methods:
- Mice knee joints were injected with Na-Phde a at concentrations of 560 or 280 micromol/L.
- Percutaneous laser irradiation (664 nm, 125 mW, 5 min) was applied 30 minutes post-injection.
- Joint swelling, body weight, and histological changes in knee joints were monitored.
Main Results:
- Transient joint swelling was observed for up to 3 weeks post-PDT (p < 0.05).
- Histological analysis revealed temporary inflammatory changes, primarily in the synovial tissue, within 1 week.
- No significant long-term effects were noted on cartilage, bone marrow, or menisci by 8 weeks.
Conclusions:
- PDT using Na-Phde a induced transient, reversible arthritis in normal joint tissue.
- The treatment did not result in osteoarthritic changes, indicating a favorable safety profile.
- These findings suggest PDT with Na-Phde a is a potentially safe and effective option for treating bacterial septic arthritis.
