Effect of blue light on the proliferation of human gingival fibroblasts

Taoufik, K.; Mavrogonatou, E.; Eliades, T.; Papagiannoulis, L.; Eliades, G.; Kletsas, D.

doi:10.1016/j.dental.2007.10.006

« Previous Next »Dental Materials
Volume 24, Issue 7 , Pages 895-900, July 2008

Effect of blue light on the proliferation of human gingival fibroblasts

K. Taoufik
- Department of Paediatric Dentistry, School of Dentistry, University of Athens, Greece
E. Mavrogonatou
- Laboratory of Cell Proliferation and Ageing, Institute of Biology, National Center for Scientific Research ‘Demokritos’, Aghia Paraskevi, Athens, Greece
T. Eliades
- Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Greece
L. Papagiannoulis
- Department of Paediatric Dentistry, School of Dentistry, University of Athens, Greece
G. Eliades
- Department of Biomaterials, School of Dentistry, University of Athens, Greece
D. Kletsas
- Laboratory of Cell Proliferation and Ageing, Institute of Biology, National Center for Scientific Research ‘Demokritos’, Aghia Paraskevi, Athens, Greece
- Corresponding author. Tel.: +30 2106503565; fax: +30 2106511767.

Received 11 September 2007; received in revised form 29 October 2007; accepted 29 October 2007.

Abstract

Objectives

Previous studies have reported that blue light, under conditions similar to those used for orthodontic bonding, influences several aspects of cellular physiology. The purpose of this study was to investigate the effect of the exposure to blue light curing sources, i.e. halogen, light emitting diode (LED) and plasma arc irradiation, on the proliferation of human gingival fibroblasts.

Methods

Primary cultures of human gingival fibroblasts were exposed to halogen, LED and plasma arc irradiation for 240, 180 and 120s, respectively. The effect of blue light on DNA synthesis and cell proliferation was estimated by tritiated thymidine incorporation and direct cell counting, respectively. The possible involvement of an oxidative stress on the effect of blue light irradiation was studied by using N-acetyl-cysteine. Finally the formation of DNA double-strand breaks after irradiation was studied by immunofluorescence with an antibody against histone H₂A.x phosphorylated in Ser139.

Results

Blue light showed no immediate effect on the regulation of DNA synthesis. However, exposure of cells to these light sources inhibits cell proliferation measured one week after irradiation. This phenomenon is not attributed to the formation of DNA double strand breaks and cannot be annulled by N-acetyl-cysteine.

Significance

The results presented here indicate a mild inhibition of gingival fibroblasts’ proliferation after exposure to blue light and necessitate further study to clarify the exact mechanism underlying this effect.

Keywords: Blue light, Gingival fibroblatsts, Proliferation, DNA breaks, Oxidative stress