GENE EXPRESSION PROFILING OF FIMA FIMBRIAE IN PORPHYROMONAS GINGIVALIS STRAINS IN RESPONSE TO PHOTO-ACTIVATED DISINFECTION THERAPY

Background and Aim:The endodontic infection therapy majorly aims to eradicate the microbial pathogens. Photo-activated disinfection (PAD), also known as antimicrobial photodynamic therapy, is an alternative antimicrobial modality used to control the microorganisms causing endodontic infections. The present study assessed the effects of PAD on expression profiling of the gene associated with the biofilm formation being the most essential virulence factor in Porphyromonas gingivalis strain cells.Methods:Sixteen clinical strains of P. gingivalis that were isolated in vivo, were further photosensitized with toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizing agents, which were excited with specific wavelength of light based on the photosensitizer. After evaluating sub-lethal dose of PAD (sPAD), its effects on the fimA gene expression were assessed using real-time quantitative reverse transcription PCR (qRT-PCR).Results:In this study, maximum values of sPAD against P. gingivalis were 6.25 μg/mL TBO at a fluency of 171.87 J/cm2, 15.6 μg/mL ICG at fluency of 15.6 J/cm2, and 25 μg/mL MB at fluency of 93.75 J/cm2. MB-, TBO-, and ICG-sPAD could cause about 4.6-, 14.4-, and 17.3-fold suppression of fimA expression, respectively. P. gingivalis strains expressed less virulence in cells surviving PAD.Conclusion:The gene expression profiling reduced in the bacterial cells, wherein greater reduction was observed for ICG-sPAD than TBO- and MB-sPAD.

Keywords:

gene expression , indocyanine green , methylene blue , photo-activated disinfection , Porphyromonas gingivalis , toluidine blue O