Effect of photodynamic therapy based on indocyanine green on expression of apoptosis-related genes in human gingival fibroblast cells

Background: Periodontal diseases refer to inflammation of the gingiva, induction of Apoptosis in human gingival fibroblast cells, destruction of the surrounding tissues, and early bone loss resulting in infections due to the pathogenic activity of the Microorganisms and the host immune inflammatory responses. Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an adjunct treatment therapy for periodontal infections.

Aim: To prove the lack of side effects of PDT on periodontal tissues, we investigated the expression of Bax and Bcl-2 genes that are involved in Apoptosis after the PDT on human gingival fibroblast (HGF) cells.

Materials and methods: In this study the effect of PDT based on indocyanine green (ICG) as a photosensitizer with the diode laser were tested on the expression of Bax and Bcl-2 genes in monolayers of HGF cells. The effects of PDT on the expression of Bax and Bcl-2 genes were evaluated by real-time quantitative Reverse transcription PCR.

Results: The results of the genes expression analysis revealed that ICG-PDT at concentrations 1000μg/mL, induced the significant expression of Bax in HGF cells; however, the laser irradiation as well as ICG showed no significant effects on the expression of these genes. Treatment with ICG alone, laser irradiation and ICG-PDT caused no observable Bcl-2 gene expression changes between the tested and control groups.

Conclusion: Our findings indicate that ICG-PDT at 1000μg/mL of ICG with the exposure time of 60s for the diode laser would appear to be an inducer of Apoptosis in HGF at transcriptome level.