Real-time quantitative reverse transcription-PCR analysis of expression stability of Aggregatibacter actinomycetemcomitans fimbria-associated gene in response to photodynamic therapy

Publication date: June 2017
Source:Photodiagnosis and Photodynamic Therapy, Volume 18
Author(s): Maryam Pourhajibagher, Abbas Monzavi, Nasim Chiniforush, Mohammad Moein Monzavi, Shaghayegh Sobhani, Sima Shahabi, Abbas Bahador
BackgroundAggregatibacter actinomycetemcomitans is an etiological agent of both chronic and aggressive periodontitis. Dissemination of A. actinomycetemcomitans from the oral cavity and initiation of systemic infections has led to new approaches for treatment being needed. In this study, a series of experiments presented investigated the effect of methylene blue (MB)-mediated antimicrobial photodynamic therapy (aPDT) on cell viability and expression of fimbria-associated gene (rcpA) in A. actinomycetemcomitans.Materials and methodsTo determine the dose-depended effects of aPDT, A. actinomycetemcomitans ATCC 33384 strain photosensitized with MB was irradiated with diode laser following bacterial viability measurements. Cell-surviving assay and expression ratio of rcpA were assessed by colony forming unit and real-time quantitative reverse transcription-PCR (qRT-PCR) assays, respectively.ResultsIn the current study, MB-mediated aPDT using 100μg/mL showed significant reduction in A. actinomycetemcomitans growth when compared to the control (P<0.05). Sub-lethal dose of aPDT against A. actinomycetemcomitans was 25μg/mL MB at fluency of 93.75J/cm². Sub-lethal dose of aPDT could lead to about four-fold suppression of expression of rcpA.ConclusionHigh doses of MB-mediated aPDT could potentially exhibit antimicrobial activity, and the expression of rcpA as an important virulence factor of this strain is reduced in cells surviving aPDT with MB. So, aPDT can be a valuable tool for the treatment of A. actinomycetemcomitans infections.



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