Application of Different Wavelengths of LED Lights in Antimicrobial Photodynamic Therapy for the Treatment of Periodontal Disease.

Therapeutic light has been increasingly used in clinical dentistry for surgical ablation, disinfection, bio-stimulation, reduction in inflammation, and promotion of wound healing. Photodynamic therapy (PDT), a type of phototherapy, has been used to selectively destroy tumor cells. Antimicrobial PDT (a-PDT) is used to inactivate causative bacteria in infectious oral diseases, such as periodontitis. Several studies have reported that this minimally invasive technique has favorable therapeutic outcomes with a low probability of adverse effects. PDT is based on the photochemical reaction between light, a photosensitizer, and oxygen, which affects its efficacy. Low-power lasers have been predominantly used in phototherapy for periodontal treatments, while light-emitting diodes (LEDs) have received considerable attention as a novel light source in recent years. LEDs can emit broad wavelengths of light, from infrared to ultraviolet, and the lower directivity of LED light appears to be suitable for plaque control over large and complex surfaces. In addition, LED devices are small, lightweight, and less expensive than lasers. Although limited evidence exists on LED-based a-PDT for periodontitis, a-PDT using red or blue LED light could be effective in attenuating bacteria associated with periodontal diseases. LEDs have the potential to provide a new direction for light therapy in periodontics.

The effect of antimicrobial photodynamic therapy using yellow-green LED and rose bengal on Porphyromonas gingivalis.

INTRODUCTION: This study aimed to investigate the effects of a new antimicrobial photodynamic therapy (aPDT) system using yellow-green light-emitting diode (YGL) and rose bengal (RB) on Porphyromonas gingivalis (Pg) in vitro. MATERIALS AND METHODS: Pg suspension mixed with RB was irradiated with YGL (565 nm) or blue light-emitting diode (BL, 470 nm) at 428 mW/cm2 in comparison with chlorhexidine (CHG) treatment. The cells were cultured anaerobically on agar plates, and the number of colony-forming units (CFU) was determined. The treated suspension was anaerobically incubated, and the cell density (OD600nm) was monitored for 24 h. Also, the viability of treated human gingival fibroblast (HGF-1) was measured using WST-8 assay. Pg morphology was observed with a scanning electron microscope. The RNA integrity number of aPDT-treated Pg was determined and gene expressions were evaluated by quantitative real-time polymerase chain reaction. RESULTS: RB + YGL (aPDT) demonstrated a significantly higher reduction of CFU, compared to RB + BL (aPDT) and CHG, furthermore the OD value rapidly decreased. Morphological changes of Pg with RB + YGL were more severe than with CHG. Although RB + YGL reduced HGF-1 viability, aPDT's impact was significantly lower than CHG's. With RB + YGL treatment, RIN values decreased; furthermore, gene expressions associated with DNA replication and cell division were remarkably decreased after 12 h. CONCLUSION: The results of this study demonstrated that a novel aPDT system using RB + YGL may have potential as a new technical modality for bacterial elimination in periodontal therapy.

Increased cell proliferation and differential protein expression induced by low-level Er:YAG laser irradiation in human gingival fibroblasts: proteomic analysis.

Erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment has demonstrated favorable wound healing effect after periodontal therapy. One of the reasons may be the positive biological effect of the low-level laser on the irradiated tissues, although the mechanism remains unclear. The aim of this study was to investigate the effect of low-level Er:YAG laser irradiation on cell proliferation and laser-induced differential expression of proteins in human gingival fibroblasts (HGFs) by proteomic analysis. In the first experiment, HGFs were exposed to low-level Er:YAG laser irradiation and the laser-induced cell proliferation and damage were evaluated on day 3. In the second experiment, proteomic analysis was performed on day 1 after irradiation. The peptides prepared from HGFs were analyzed by a hybrid ion trap-Fourier transform mass spectrometer, Mascot search engine, and UniProtKB database. A significant increase in cell proliferation without cell damage after irradiation was observed. Among the total identified 377 proteins, 59 proteins, including galectin-7, which was associated with the process of wound healing, were upregulated and 15 proteins were downregulated in laser-treated HGFs. In the third experiment, the increase in messenger RNA (mRNA) and protein expression of galectin-7 in the irradiated HGFs was validated by various analytical techniques. In addition, the effect of recombinant human galectin-7 on the modulation of HGFs proliferation was confirmed. The results indicate that low-level Er:YAG laser irradiation can promote HGF proliferation and induce a significant change in protein expression and the upregulation of galectin-7 expression may partly contribute to the increase in cell proliferation.

Effect of black-currant extract on negative lens-induced ocular growth in chicks.

AIM: To evaluate the effects of orally administered black-currant (BC) extract on the enlargement of globe component dimensions induced in chicks by wearing negative lenses. METHODS: Negative lenses (-8 D) were worn on the right eyes by 8-day-old chicks, and their fellow eyes acted as controls. BC extract and distilled water (vehicle control) were orally administered once a day for 3 days. To confirm the effect of BC anthocyanins (BCAs), they were intravenously administered once a day for 3 days. Dimensions of globe components of right eyes and fellow eyes were measured with an A-scan ultrasound instrument on the third day (day 4) after placement of the negative lenses. RESULTS: Orally administered BC extract significantly inhibited enlargement of vitreous-chamber depth, axial and ocular lengths in a dose-dependent manner when compared to controls. Intravenously administered BCAs also inhibited elongation of vitreous-chamber depth and axial length when compared to controls. CONCLUSIONS: This is the first evidence that BC extract and BCAs could inhibit enlargement of globe component dimensions in a negative lens-induced chick myopia model.

Development and validation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of four anthocyanins in human plasma after black currant anthocyanins ingestion.

Black currant anthocyanins consist of delphinidin-3-glucoside (1), delphinidin-3-rutinoside (2), cyanidin-3-glucoside (3), and cyanidin-3-rutinoside (4). A liquid chromatography tandem mass spectrometry method for simultaneous determination of four anthocyanins in human plasma was developed and validated. Samples were prepared using solid phase extraction, followed by chromatographic separation with a reverse phase C(18) column with gradient elution using mobile phases containing water, acetonitrile, and formic acid. The quantification of four anthocyanins was determined by multiple reaction monitoring using electrospray ionization. The method showed good selectivity, sensitivity (limits of quantification for four anthocyanins were 0.2 nmol/L), linearity (0.2-20 nmol/L; r > 0.999), intra- and interday precision, accuracy (<14%), and recovery (62.5-85.7%). Analyte stability was investigated in detail. This method was successfully applied to the determination of delphinidin-3-glucoside (1), delphinidin-3-rutinoside (2), cyanidin-3-glucoside (3), and cyanidin-3-rutinoside (4) concentrations in human plasma after ingestion of a single dose of black currant anthocyanins (87.9 micromol (58.8 mg) total anthocyanins).