Anti-inflammatory effect of 635 nm irradiations on in vitro direct/indirect irradiation model.

Low-level laser therapy (LLLT) has been promoted for its beneficial effects on tissue healing and pain relief. As during laser treatment it is possible to irradiate only a small area of the surface body or wound and, correspondingly, of a very small volume of the circulating blood, it is necessary to explain how its photomodification can lead to a wide spectrum of therapeutic effects. To establish the experimental model for indirect irradiation, irradiation with 635 nm was performed on immortalized human gingival fibroblasts (IGFs) in the presence of Porphyromonas gingivalis lipopolysaccharides (LPS). The irradiated medium was transferred to non-irradiated IGFs which were compared with direct irradiated IGFs. The protein expressions were assessed by Western blot, and prostaglandin E2 (PGE2 ) was measured using an enzyme-linked immunoassay. Reactive oxygen species (ROS) were measured by DCF-DA; cytokine profiles were assessed using a human inflammation antibody array. Cyclooxygenase-2 (COX-2) protein expression and PGE2 production were significantly increased in the LPS-treated group and decreased in both direct and indirect irradiated IGFs. Unlike direct irradiated IGFs, ROS level in indirect irradiated IGFs was decreased by time-dependent manners. There were significant differences of released granulocyte colony-stimulating factor (G-CSF), regulated on activated normal T-cell expressed and secreted (RANTES), and I-TAC level observed compared with direct and indirect irradiated IGFs. In addition, in the indirect irradiation group, phosphorylations of C-Raf and Erk1/2 increased significantly compared with the direct irradiation group. Thus, we suggest that not only direct exposure with 635 nm light, but also indirect exposure with 635 nm light can inhibit activation of pro-inflammatory mediators and may be clinically useful as an anti-inflammatory tool.

In vitro bactericidal effects of 625, 525, and 425 nm wavelength (red, green, and blue) light-emitting diode irradiation.

OBJECTIVE: The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria. BACKGROUND DATA: Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described. Before conducting clinical trials, the appropriate wavelength with reasonable dose and exposure time should be established. MATERIALS AND METHODS: The bactericidal effects of 625, 525, and 425 nm wavelength LED irradiation were investigated in vitro for the anaerobic bacterium Porphyromonas gingivalis and two aerobes (Staphylococcus aureus and Escherichia coli DH5α). Average power output was 6 mW/cm(2) for 1 h. The bacteria were exposed to LED irradiation for 1, 2, 4, and 8 h (21.6, 43.2, 86.4, and 172.8 J/cm(2), respectively). LED irradiation was performed during growth on agar and in broth. Control bacteria were incubated without LED irradiation. Bacterial growth was expressed in colony-forming units (CFU) and at an optical density at 600 nm in agar and broth. RESULTS: The bactericidal effect of LED phototherapy depended upon wavelength, power density, bacterial viable number, and bacteria species. The bactericidal effect of 425 and 525 nm irradiation varied depending upon the bacterial inoculation, compared with unirradiated samples and samples irradiated with red light. Especially, P. gingivalis and E. coli DH5α were killed by 425 nm, and S. aureus growth was inhibited by 525 nm. However, the wavelength of 625 nm was not bactericidal for P. gingivalis, E. coli DH5α, or S. aureus. CONCLUSIONS: Irradiation at 625 nm light was not bactericidal to S. aureus, E. coli, and P. gingivalis, whereas wavelengths of 425 and 525 nm had bactericidal effects. S. aureus was also killed at 525 nm.

Effect of 635 nm irradiation on high glucose-boosted inflammatory responses in LPS-induced MC3T3-E1 cells.

Hyperglycemia occurs in patients with poorly controlled diabetes mellitus and contributes to bone resorption and increased susceptibility to bacterial infections. Hyperglycemia can incite low-grade inflammation that can contribute to the resorption of bone, especially the periodontal bone. The increased susceptibility to periodontal infections can contribute to bone resorption through the activation of osteoclasts. In this study, the osteoblastic, clonal cell line, MC3T3-E1, was used in an in vitro model of hyperglycemia and lipopolysaccharide-induced reactive oxygen species generation to determine the potential anti-inflammatory effect of 635 nm light-emitting diode (LED) irradiation or whether 635 nm LED irradiation can be a potential anti-inflammatory treatment. LED irradiation of MC3T3-E1 cells stimulated with lipopolysaccharide in a high glucose-containing medium decreased the level of cyclooxygenase gene and protein expression and reduced the level of prostaglandin E2 expression by decreasing the amount of reactive oxygen species generation. LED irradiation also inhibited the osteoclastogenesis in MC3T3-E1 cells by regulating the receptor activator of nuclear factor kappa-B ligand and osteoprotegerin. These findings reveal the mechanisms which are important in the pathogenesis of diabetic periodontitis and highlight the beneficial effects of 635 nm LED irradiation in reducing the adverse effects of diabetic periodontitis.

Modulation of lipopolysaccharide-induced NF-κB signaling pathway by 635 nm irradiation via heat shock protein 27 in human gingival fibroblast cells.

Heat shock protein-27 (HSP27) is a member of the small HSP family which has been linked to the nuclear factor-kappa B (NF-κB) signaling pathway regulating inflammatory responses. Clinical reports have suggested that low-level light therapy/laser irradiation (LLLT) could be an effective alternative treatment to relieve inflammation during bacterial infection associated with periodontal disease. However, it remains unclear how light irradiation can modulate the NF-κB signaling pathway. We examined whether or not 635 nm irradiation could lead to a modulation of the NF-kB signaling pathway in HSP27-silenced cells and analyzed the functional cross-talk between these factors in NF-κB activation. The results showed that 635 nm irradiation led to a decrease in the HSP27 phosphorylation, reactive oxygen species (ROS) generation, I-κB kinase (IKK)/inhibitor of κB (IκB)/NF-κB phosphorylation, NF-κB p65 translocation and a subsequent decrease in the COX-1/2 expression and prostaglandin (PGE(2) ) release in lipopolysaccharide(LPS)-induced human gingival fibroblast cells (hGFs). However, in HSP27-silenced hGFs, no obvious changes were observed in ROS generation, IKK/IκB/NF-κB phosphorylation, NF-κB p65 translocation, nor in COX-1/2 expression, or PGE(2) release. This could be a mechanism by which 635 nm irradiation modulates LPS-induced NF-κB signaling pathway via HSP27 in inflammation. Thus, HSP27 may play a role in regulating the anti-inflammatory response of LLLT.

Dichloromethane fraction from Gardenia jasminoides: DNA topoisomerase 1 inhibition and oral cancer cell death induction.

CONTEXT: A growing body of evidence shows that compounds of plant origin have the ability to prevent cancer. The fruit of gardenia, Gardenia jasminoides Ellis (Rubiaceae), has long been used as a food additive and herbal medicine, and its pharmacological actions, such as protective activity against oxidative damage, cytotoxic effect, and anti-inflammatory and anti-tumor activity, have already been reported. OBJECTIVE: The purpose of the present study was to investigate the presence of DNA topoisomerase 1 inhibitor in various solvent fractions of Gardenia extract and examine the induction of oral cancer cell death upon treatment with Gardenia extract. MATERIALS AND METHODS: The methanol extract of Gardenia was partitioned with n-hexane, dichloromethane, ethyl acetate, n-butanol, and water. RESULTS: In the DNA topoisomerase 1 assay, n-hexane and dichloromethane fractions inhibited topoisomerase 1 and led to a decrease in the cell viability of KB cells. The dichloromethane fraction (0.1 mg/mL) also showed 77% inhibition of cell viability in KB cells compared with HaCaT cells. Treatment with dichloromethane fraction led to apoptotic cell death as evidenced by flow cytometric analysis and morphological changes. In addition, treatment with Gardenia extract dichloromethane fraction led to the partial increase of caspase-3, caspase-8 and caspase-9 activities and the cleavage of poly (ADP-ribose) polymerase. CONCLUSION: Taken together, these results suggest that the dichloromethane fraction from Gardenia extract induces apoptotic cell death by DNA topoisomerase 1 inhibition in KB cells. These findings suggest the possibility that Gardenia extract could be developed as an anticancer modality.

The anti-inflammatory mechanism of 635 nm light-emitting-diode irradiation compared with existing COX inhibitors.

BACKGROUND AND OBJECTIVES: Inhibition of cyclooxygenase (COX) and prostaglandin E(2) (PGE(2)) protects cells against cell injury in specific pathophysiological situations: inflammation and oxidative stress. Although the anti-inflammatory effects have been reported in clinical fields for specific wavelength irradiation during wound healing, the physiological mechanism has not been clarified yet. The aim of the present study is to investigate the anti-inflammatory mechanism of 635 nm light-emitting-diode (LED) irradiation compared with existing COX inhibitors. STUDY DESIGN/MATERIALS AND METHODS: The present study investigated anti-inflammatory effects of 635 nm irradiation on PGE(2) release, COX and phospholipase A(2) (PLA(2)) expression, and reactive oxygen species (ROS) dissociation in arachidonic acid (AA)-treated human gingival fibroblast (hGF). These results were compared with their existing COX inhibitors: indomethacin and ibuprofen. The PGE(2) release was measured by enzyme immunoassay, the COX expression was measured by western blot and reverse transcriptase polymerase chain reaction (RT-PCR), and ROS level was measured by flow cytometry, laser scanning confocal microscope and RT-PCR. RESULTS: Results showed that 635 nm irradiation and existing COX inhibitors inhibit expression of COX and PGE(2) release. Unlike indomethacin and ibuprofen, 635 nm irradiation leads to a decrease of ROS levels and mRNA expression of cytosolic phospholipase A(2) (cPLA(2)) and secretary phospholipase A(2) (sPLA(2)). CONCLUSION: Taken together, 635 nm irradiation, unlike indomethacin and ibuprofen, can directly dissociate the ROS. This inhibits cPLA(2), sPLA(2), and COX expression, and results in the inhibition of PGE(2) release. Thus, we suggest that 635 nm irradiation inhibits PGE(2) synthesis like COX inhibitor and appears to be useful as an anti-inflammatory tool.