title: Effect of helium/neon laser irradiation on nerve growth factor synthesis and secretion in skeletal muscle cultures.
abstract: Low energy laser irradiation therapy in medicine is widespread but the mechanisms are not fully understood. The aim of the present study was to elucidate the mechanism by which the light might induce therapeutic effects. Skeletal muscle cultures were chosen as a target for light irradiation and nerve growth factor (NGF) was the biochemical marker for analysis. It was found that there is a transient elevation of intracellular calcium in the myotubes immediately after irradiation (P<0.001). Preincubation of the myotubes with either the photosensitizers 5-amino-levulinic acid (5-ALA), or with hematoporphyrin (Hp) enhanced the elevation of cytosolic calcium (P<0.001) after helium/neon irradiation (633 nm) with an energy of 3 J/cm(2). In addition, helium/neon irradiation augmented the level of NGF mRNA fivefold and increased NGF release to the medium of the myotubes. Thus, it is speculated that transient changes in calcium caused by light can modulate NGF release from the myotubes and also affect the nerves innervating the muscle. The NGF is probably responsible for the beneficial effects of low-level light.
authors.affiliation: Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Fidi
authors.initials: F
authors.lastname: Schwartz
authors.forename: Chaya
authors.initials: C
authors.lastname: Brodie
authors.forename: Elana
authors.initials: E
authors.lastname: Appel
authors.forename: Gila
authors.initials: G
authors.lastname: Kazimirsky
authors.forename: Asher
authors.initials: A
authors.lastname: Shainberg
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D006371:Helium; D007834:Lasers; D051379:Mice; D018482:Muscle, Skeletal / Q000502:physiology* / Q000528:radiation effects; D009356:Neon; D020932:Nerve Growth Factor / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014158:Transcription, Genetic / Q000528:radiation effects
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D006371:Helium; D009356:Neon; D020932:Nerve Growth Factor