J Dent Hyg Sci.  2019 Jun;19(2):133-140. 10.17135/jdhs.2019.19.2.133.

Inflammatory Effect of Light-Emitting Diodes Curing Light Irradiation on Raw264.7 Macrophage

• Jeong MJ
• Kil KS
• Lee MH
• Lee SY
• Lee HJ
• Lim DS
• Jeong SJ

• KMID: 2451791
• DOI: http://doi.org/10.17135/jdhs.2019.19.2.133

Abstract

BACKGROUND
The light-emitting diode (LED) curing light used is presumed to be safe. However, the scientific basis for this is unclear, and the safety of LED curing light is still controversial. The purpose of this study was to investigate the effect of LED curing light irradiation according to the conditions applied for the polymerization of composite resins in dental clinic on the cell viability and inflammatory response in Raw264.7 macrophages and to confirm the stability of LED curing light.
METHODS
Cell viability and cell morphology of Raw264.7 macrophages treated with 100 ng/ml of lipopolysaccharide (LPS) or/and LED curing light with a wavelength of 440~490 nm for 20 seconds were confirmed by methylthiazolydiphenyl-tetrazolium bromide assay and microscopic observation. The production of nitric oxide (NO) and prostaglandin E2 (PGE2) was confirmed by NO assay and PGE2 enzyme-linked immunosorbent assay kit. Expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in total RNA and protein was confirmed by reverse transcription polymerase chain reaction and Western blot analysis.
RESULTS
The LED curing light did not affect the viability and morphology of normal Raw264.7 cells but affected the cell viability and induced cytotoxicity in the inflammation-induced Raw264.7 cells by LPS. The irradiation of the LED curing light did not progress to the inflammatory state in the inflammation-induced Raw264.7 macrophage. However, LED curing light irradiation in normal Raw264.7 cells induced an increase in NO and PGE2 production and mRNA and protein expression of IL-1β and TNF-α, indicating that it is possible to induce the inflammatory state.
CONCLUSION
The irradiation of LED curing light in RAW264.7 macrophage may induce an excessive inflammatory reaction and damage oral tissues. Therefore, it is necessary to limit the long-term irradiation which is inappropriate when applying LED curing light in a dental clinic.

Keyword

Inflammatory effect; Light-emitting diode; Light curing light; Macrophage; Raw264.7 cell

MeSH Terms

Blotting, Western
Cell Survival
Composite Resins
Dental Clinics
Dinoprostone
Enzyme-Linked Immunosorbent Assay
Interleukins
Macrophages*
Nitric Oxide
Polymerase Chain Reaction
Polymerization
Polymers
Reverse Transcription
RNA
RNA, Messenger
Tumor Necrosis Factor-alpha
Composite Resins
Dinoprostone
Interleukins
Nitric Oxide
Polymers
RNA
RNA, Messenger
Tumor Necrosis Factor-alpha