Anti-inflammatory effects of low-level laser therapy on human periodontal ligament cells: in vitro study

Abstract

Periodontal disease is a chronic inflammatory disease that is commonly treated with surgical and nonsurgical techniques. However, both approaches have limitations. Low-level laser therapy (LLLT) has been widely applied in reducing inflammatory reactions, and research indicates that LLLT induces an anti-inflammatory effect that may enhance periodontal disease therapy. The purpose of this study was to investigate the anti-inflammatory effect of LLLT on human periodontal ligament cells (hPDLCs) in an inflammatory environment and aimed to determine the possible mechanism of action. Cells were cultured and treated with or without lipopolysaccharide (LPS) from Porphryromonas gingivalis or Escherichia coli, followed by irradiation with a gallium-aluminum-arsenide (GaAlAs) laser (660 nm) at an energy density of 8 J/cm2. Quantitative real-time polymerase chain reactions were used to assess the expression of pro-inflammatory genes, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8. The dual-luciferase reporter assay was used to examine nuclear factor-κB (NF-κB) transcriptional activity. An enzyme-linked immunosorbent assay was used to monitor the concentration of intracellular cyclic adenosine monophosphate (cAMP). Both LPS treatments significantly induced the mRNA expression of pro-inflammatory cytokines. However, LLLT inhibited the LPS-induced pro-inflammatory cytokine expression and elevated intracellular levels of cAMP. The LLLT inhibitory effect may function by downregulating NF-κB transcriptional activity and by increasing the intracellular levels of cAMP. LLLT might inhibit LPS-induced inflammation in hPDLCs through cAMP/NF-κB regulation. These results should be further studied to improve periodontal therapy.

Cyclic compression emerged dual effects on the osteogenic and osteoclastic status of LPS-induced inflammatory human periodontal ligament cells according to loading force

“…The miRNA expression patterns were investigated in the inflammatory hPDLCs induced by 0, 0.5, 1.0, 1.5 and 2.0 μg/ml of LPS [23]. What's more, the scholars also applied 0, 10, 20, 50, and 100 μg/ml of LPS on hPDLCs to make an inflammatory environment, and aimed to investigate the anti-inflammatory effect of a certain therapy [24]. So, we selected the concentrations of 0.1, 1.0, 10, 100 and 500 μg/ml to make clear the appropriate working dosage of LPS in the inflammation induction of hPDLCs in vitro.…”

Multiple sessions of antimicrobial photodynamic therapy associated with surgical periodontal treatment in patients with chronic periodontitis

“…A possible explanation for this finding is the potential beneficial effect of low-power laser on tissue healing, which inhibits the expression of proinflammatory cytokines, reducing local inflammatory reactions. 45 Among the limitations of the present study, probably the 90-day interval for reassessment of the therapeutic effects is too long for confirmation of microbiological results and should therefore be reconsidered. 46 A suggestion for future studies is to consider additional 30 and/or 60 postoperative days, as well as periodontal supportive care.…”

“…Despite the hypothesis of the subgingival microbiota recolonization at the end of the study, significant clinical improvement of PD and CAL in the TG was maintained at 90 postoperative days. A possible explanation for this finding is the potential beneficial effect of low‐power laser on tissue healing, which inhibits the expression of proinflammatory cytokines, reducing local inflammatory reactions …”

Cyclic compression emerged dual effects on the osteogenic and osteoclastic status of LPS-induced inflammatory human periodontal ligament cells according to loading force

“…The miRNA expression patterns were investigated in the inflammatory hPDLCs induced by 0, 0.5, 1.0, 1.5 and 2.0 μg/ml of LPS [23]. What's more, the scholars also applied 0, 10, 20, 50, and 100 μg/ml of LPS on hPDLCs to make an inflammatory environment, and aimed to investigate the anti-inflammatory effect of a certain therapy [24]. So, we selected the concentrations of 0.1, 1.0, 10, and 500 μg/ml to make clear the appropriate working dosage of LPS in the inflammation induction of hPDLCs in vitro.…”