title: Increased mobility and stem-cell proliferation rate in Dugesia tigrina induced by 880nm light emitting diode.
abstract: The therapeutic effects elicited by photobiostimulation in the near infrared range may be associated with increased proliferation rate of particular cell-types. The present study utilized commercial light emitting diodes to investigate the effects of low-level near-infrared radiation on the proliferation rate of stem cells in amputated planarian. Whole and amputated animals were exposed to either ambient diurnal lighting, darkness, white light, red light, or near-infrared (880 nm) light. Irradiation was consistent for the duration of the experiments and was provided using commercial 5mm light emitting diodes (∼1.0 mW/m(2) in power density and ∼0.01 J/cm(2) in radiant exposure). Compared to other groups amputated planarian exposed to near-infrared displayed increased mobility by the 3rd day of exposure (F((4,26))=4.31, p<0.04, η(2)=41%). Higher densities of stem cells were measured in these worms 84 h post injury (F((4,72))=4.78, p<0.01, η(2)=21%). These findings suggest that non-coherent light sources with power-densities about 1000 times lower than contemporary low-power laser settings remain effective in generating photobiostimulation effects and warrants further investigation on stem-cell proliferation induced by near-infrared light emitting diodes.
authors.affiliation: Laurentian University, Sudbury, Ontario, Canada. hp_wu@laurentian.ca
authors.forename: Hsia-Pai Patrick
authors.initials: HP
authors.lastname: Wu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Persinger
mesh_terms: D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D028022:Low-Level Light Therapy; D010932:Planarians / Q000166:cytology / Q000528:radiation effects*; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors