Inactivation of Proteolytic Enzymes from Porphyromonas gingivalis Using Light-activated Agents

Area of Science:

• Microbiology
• Periodontology
• Photochemistry

Background:

• Porphyromonas gingivalis is a primary causative agent of periodontitis.
• Toluidine blue O (TBO) is a photosensitizer that can be activated by red light.
• Previous research indicates TBO and red light exhibit bactericidal effects against P. gingivalis.

Purpose of the Study:

• To investigate the impact of red light irradiation in the presence of TBO on the proteolytic enzyme activity of P. gingivalis.
• To assess the potential of photodynamic therapy in mitigating the virulence of P. gingivalis.

Main Methods:

• Bacterial suspensions of P. gingivalis were exposed to 633 nm red light with varying concentrations of TBO.
• Proteolytic activity was quantified by measuring azocasein hydrolysis at different time points.
• Enzyme activity was analyzed following TBO-mediated photodynamic treatment.

Main Results:

• Exposure to 126 J of red light and 12.5 µg/ml TBO resulted in a 100% reduction in proteolytic enzyme activity.
• The primary virulence factor of P. gingivalis, its proteolytic enzymes, were significantly inactivated.

Conclusions:

• Red light combined with TBO effectively inactivates the proteolytic activity of P. gingivalis.
• Photodynamic therapy presents a promising strategy for reducing the pathogenic role of P. gingivalis in periodontitis.
• This approach may be crucial in managing periodontitis by targeting key virulence factors.