title: Paramecium: a promising non-animal bioassay to study the effect of 808 nm infrared diode laser photobiomodulation.
abstract: OBJECTIVE
  Photobiostimulation and photobiomodulation (PBM) are terms applied to the manipulation of cellular behavior using low intensity light sources, which works on the principle of inducing a biological response through energy transfer. The aim of this investigation was to identify a laboratory assay to test the effect of an infrared diode laser light (808 nm) on cell fission rate.
  
  
  METHODS
  Sixty cells of Paramecium primaurelia were divided in two groups of 30. The first group (test group) was irradiated, at a temperature of 24°C, for 50 sec by a 808 nm diode laser with a flat top handpiece [1 cm of spot diameter, 1 W in continuous wave (CW), 50 sec irradiation time, 64 J/cm(2) of fluence]. The second group (control group) received no laser irradiation. All cells were transferred onto a depression slide, fed, and incubated in a moist chamber at a temperature of 24°C. The cells were exposed and monitored for 10 consecutive fission rates. Changes in temperature and pH were also evaluated.
  
  
  RESULTS
  The exposed cells had a fission rate rhythm faster than the control cells, showing a binary fission significantly (p<0.05) shorter than unexposed cells. No significant effects of laser irradiation on pH and temperature of Paramecium's lettuce infusion medium were observed.
  
  
  CONCLUSIONS
  The 808 nm infrared diode laser light, at the irradiation parameters used in our work, results in a precocious fission rate in P. primaurelia cells, probably through an increase in metabolic activity, secondary to an energy transfer.
authors.affiliation: 1 Department of Earth, Environment and Life Sciences (DISTAV), University of Genoa , Genoa, Italy .
authors.forename: Andrea
authors.initials: A
authors.lastname: Amaroli
authors.forename: Steven
authors.initials: S
authors.lastname: Parker
authors.forename: Gianluca
authors.initials: G
authors.lastname: Dorigo
authors.forename: Alberico
authors.initials: A
authors.lastname: Benedicenti
authors.forename: Stefano
authors.initials: S
authors.lastname: Benedicenti
mesh_terms: D001681:Biological Assay / Q000379:methods*; D004735:Energy Transfer; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy / Q000295:instrumentation*; D010247:Paramecium / Q000528:radiation effects*