Affiliations 

  • 1 Laboratory of New Model Organism (NeMo LAB), Department of Earth, Environmental and Life Sciences, University of Genova, Genova, Italy
  • 2 School of Biosciences and Veterinary Medicine, University of Camerino, Camerino,Macerata, Italy
  • 3 Laser Therapy Centre, Department of Surgical and Diagnostic Sciences (D.I.S.C), University of Genova, Genova, Italy; Faculty of Therapeutic Stomatology, Institute of Dentistry, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
  • 4 Laser Therapy Centre, Department of Surgical and Diagnostic Sciences (D.I.S.C), University of Genova, Genova, Italy; University of Technology MARA, Department of Dentistry, Sungai Buloh, Malaysia
  • 5 Department of Experimental Medicine, University of Genova, Genova, Italy
  • 6 Department of Orthopaedic Dentistry, Sechenov First Moscow State Medical University, Trubetzkaya St., 8, Bd. 2, 119991 Moscow, Russian Federation
  • 7 Laser Therapy Centre, Department of Surgical and Diagnostic Sciences (D.I.S.C), University of Genova, Genova, Italy
  • 8 Laser Therapy Centre, Department of Surgical and Diagnostic Sciences (D.I.S.C), University of Genova, Genova, Italy; Department of Orthopaedic Dentistry, Sechenov First Moscow State Medical University, Trubetzkaya St., 8, Bd. 2, 119991 Moscow, Russian Federation. Electronic address: andrea.amaroli.71@gmail.com
J. Photochem. Photobiol. B, Biol., 2019 Oct;199:111627.
PMID: 31536925 DOI: 10.1016/j.jphotobiol.2019.111627

Abstract

Photobiomodulation relies on the transfer of energy from incident photons to a cell photoacceptor. For many years the concept of photobiomodulation and its outcome has been based upon a belief that the sole receptor within the cell was the mitochondrion. Recently, it has become apparent that there are other photoacceptors operating in different regions of the electromagnetic spectrum. Alternative photoacceptors would appear to be water and mechanisms regulating calcium homeostasis, despite a direct effect of laser photonic energy on intracellular calcium concentration outwith mitochondrial activity or influence, have not been clearly demonstrated. Therefore, to increase the knowledge of intracellular‑calcium and laser photon interaction, as well as to demonstrate differences in irradiation profiles with modern hand-pieces, we tested and compared the photobiomodulatory effect of 808 nm and 980 nm diode laser light by low- and higher-energy (60s, 100 mW/cm2, 100 mW/cm2, 500 mW/cm2, 1000 mW/cm2, 1500 mW/cm2, 2000 mW/cm2) irradiated with a "standard" (Gaussian fluence distribution) hand-piece or with a "flat-top" (uniform fluence) hand-piece. For this purpose, we used the eukaryote unicellular-model Dictyostelium discoideum. The 808 nm and 980 nm infrared laser light, at the energy tested directly affect the stored Ca2+ homeostasis, independent of the mitochondrial respiratory chain activities. From an organism perspective, the effect on Ca2+-dependent signal transduction as the regulator of spore germination in Dictyostelium, demonstrates how a cell can respond quickly to the correct laser photonic stimulus through a different cellular pathway than the known light-chromophore(mitochondria) interaction. Additionally, both hand-piece designs tested were able to photobiomodulate the D. discoideum cell; however, the hand-piece with a flat-top profile, through uniform fluence levels allows more effective and reproducible effects.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.