IADR Abstract Archives
Photobiomodulatory Effect of Low Level Light on Oral Fibroblasts
Objectives: Low level light therapy (LLLT) is a non-invasive treatment that utilises light in the near infra-red (NIR) and infra-red (IR) spectrum to promote tissue healing and reduce inflammation. Recently, LLLT has shown some promise in treating the chronic inflammatory oral disease periodontitis. This project aims to investigate the effect of LLLT on one of the most abundant cell types in periodontium: human gingival fibroblasts (HGFs).
Methods: Primary HGFs were incubated overnight in 96-well plates (7000 cells/well). Cells were left untreated or stimulated with Escherichia coli Lipopolysaccharide (E.coli LPS, 0.1-1µg/ml) to induce inflammation and subsequently irradiated with a specialised LED array (400nm-830nm, 24mW/cm2, 30-480s, 0.72-11.52J/cm2). The effect of light on cell metabolic activity as a marker for tissue healing (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT)), inflammation (interlukin-8 (IL-8), enzyme linked immunosorbent assay (ELISA)) and reactive oxygen species (ROS) production were assessed 24hrs post irradiation. Data were then analysed using one way ANOVA followed by a post-hoc tukey test (Sigma plot).
Results: Irradiation for 240s (5.76J/cm2) induced a 12% increase in cell metabolic activity at 400nm relative to the non-irradiated (N-IR) control (p<0.05). Irradiation of untreated HGFs for 240s at 450nm caused a 15% increase in ROS production and a 27% increase in IL-8 secretion relative to the non-irradiated control (p<0.05). Conversely, irradiation of LPS treated cells for 240s at 450nm induced a decrease in IL-8 secretion of 31.8% relative to control (p<0.05). Phototherapy for 240s at 525nm also induced a decrease in ROS production of 8% relative to the non-irradiated control (p<0.05).
Conclusions: LLLT has a biomodulatory effect on HGFs where light induces a decrease in ROS and IL-8 production under inflammatory conditions but induces an increase when cells are left unstimulated. This could prove beneficial in reducing inflammation in periodontitis.
Methods: Primary HGFs were incubated overnight in 96-well plates (7000 cells/well). Cells were left untreated or stimulated with Escherichia coli Lipopolysaccharide (E.coli LPS, 0.1-1µg/ml) to induce inflammation and subsequently irradiated with a specialised LED array (400nm-830nm, 24mW/cm2, 30-480s, 0.72-11.52J/cm2). The effect of light on cell metabolic activity as a marker for tissue healing (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT)), inflammation (interlukin-8 (IL-8), enzyme linked immunosorbent assay (ELISA)) and reactive oxygen species (ROS) production were assessed 24hrs post irradiation. Data were then analysed using one way ANOVA followed by a post-hoc tukey test (Sigma plot).
Results: Irradiation for 240s (5.76J/cm2) induced a 12% increase in cell metabolic activity at 400nm relative to the non-irradiated (N-IR) control (p<0.05). Irradiation of untreated HGFs for 240s at 450nm caused a 15% increase in ROS production and a 27% increase in IL-8 secretion relative to the non-irradiated control (p<0.05). Conversely, irradiation of LPS treated cells for 240s at 450nm induced a decrease in IL-8 secretion of 31.8% relative to control (p<0.05). Phototherapy for 240s at 525nm also induced a decrease in ROS production of 8% relative to the non-irradiated control (p<0.05).
Conclusions: LLLT has a biomodulatory effect on HGFs where light induces a decrease in ROS and IL-8 production under inflammatory conditions but induces an increase when cells are left unstimulated. This could prove beneficial in reducing inflammation in periodontitis.